Friday, 15 February 2013

Using iron sulphate to control moss



My neighbours and Brenda - especially Brenda - ridicule me when they see me ‘faffing about’ with the lawn. Some men are obsessive about their lawns and I am one of them! Not in the usual way, with ride-on-mowers and rye-grass stripes, my own ambition is to create a fine fescue-grass turf. Whatever kind of lawn you have, iron sulphate will both improve it and control moss.
Including generous donations to friends and family, 25kg lasts me nearly two years.

The curriculum-vitae of this fine, white, faintly green, powder is most impressive. Not only with regular use, will it ensure a moss-free sward, it’s adherents make the following claims.
  • It’s a fertilizer that provides the essential trace element, iron. When I waxed lyrical about this, a clever student once remarked “but what about the sulphur?”. He had a good point, one of the effects of clean-air legislation has been that our soils no longer receive the essential nutrient sulphur from air pollution.
  • It promotes a beautiful green grass - much more subtle than the dark green promoted by nitrogen fertilizer.
  • Sulphate fertilizers acidify the soil and thereby encourage fine leaved grasses.
  • It discourages turf disease and from my own experience, I think this may be true
  • It is said to discourage worms but the evidence of my own pictures might cast doubt about this. I am happy to have some worms in my lawn for drainage and aeration and many species of worms only cast  below the surface. Any chemical that acidifies the soil will discourage worms.
  • It might scorch broad-leaved turf weeds. I do not regard this as significant and indeed it is an effect I try to avoid when iron sulphate drifts onto my borders.
  • It reduces frequency of mowing but not very much and it’s rather a frivolous claim. It does slightly check grass growth for a couple of weeks after application. I used to tell myself that the time I spent spreading iron sulphate was more than repaid by the time saved in mowing.

Peculiar legislation
A curious consequence  of our pesticide legislation is a result of the fact that pesticides need to be expensively registered. Iron sulphate as a moss-killer is classed as a pesticide. Iron sulphate as a fertilizer can be sold anywhere without restriction. You can use  iron sulphate on your lawn as a fertilizer, but not in theory as a moss-killer! Is that daft or is it daft?
This suits vendors absolutely fine. They can display their expensive registered moss killers (whose active ingredient is iron) and do not tell you that the cheap iron sulphate fertilizer on the next shelf is much cheaper and often superior.
Application 
For a small lawn it is convenient to dissolve it in water and apply with a watering can. In the past I would stir about a kilogram of iron sulphate in an old dustbin to make my own ‘witches brew’. 
An early lesson I learnt when I started to have my own clients was that it is not a good idea to use a knapsack sprayer. It very quickly ‘clogs its innards’.
Some gardeners spread iron sulphate in lawn sand. The purpose of the sand is to aid even spread. Some gardeners mistake the purpose of lawn sand. It is not to improve the physical condition of the soil. The quantity of sand applied when spreading moss-killer is far too small to have any appreciable effect on soil texture.
Poetry in motion

Now that I have 800 square meters of lawn all the above methods are far too slow. I now just fling it! In fact I love the way the fine powder just drifts across the lawn when on a still day I spread it. I have become quite skillful and as you will see from the pictures, I really enjoy myself! I use my lawn to integrate all my garden features and the lawn has a highly irregular shape. Despite this it takes only  half an hour to do the job. If you intend to use my drifting technique ensure that the iron sulphate you buy is powder-dry in a well sealed bag!
Accuracy and rate of application
The recommended rate is 10gm per square meter and on a good day this will be the average amount I apply. I deliberately fail to apply the iron sulphate evenly, I follow the moss! Parts of the lawn get less, some get more. When I repeat the job three months later, it all gets evened up!
When and how often
I fell in love with iron sulphate forty years ago when I read an article in a professional turf magazine written by an Irish green-keeper. He used it six times a year - but then it rains lot in Ireland and moss grows well! I apply it three or four times a year- when the whim takes me! It can be applied any time of year - but note the proviso below.
Worts and all, things that can go wrong


  • It does what it says on the tin, it kills moss and the moss goes black. (Although as stated above, it actually says nothing on the tin). Brenda’s sister was delighted with this sudden effect. Elaine, my bridge partner almost refused to play with me again but we are still together after thirty years and she has a beautiful lawn now. If your lawn is really mossy, first apply it when the grass is growing vigorously so it will cover the dead moss. If you are energetic you can rake-out dead moss. I never do!
  • If you apply it, mix it or spill it on stone surfaces it will give  a rusty stain.
  • If you have delicate hands wear gloves, especially so, if there is moisture around.
  • It has a faint seaweed smell which I rather like
  • In theory if it drifts on wet leaves of plants it will scorch them. I never find this a problem in practice and indeed in winter deliberately drift it onto my borders. Many of the plants enjoy iron sulphate too!

Is it a grenade?

You might like my recent post on lawn fertilizers

109 comments:

  1. This is interesting info. Don't know anyone here that uses it. You do look like you're having fun. :)
    Cher Sunray Gardens

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    1. Yes for me gardening is all about fun. I once made the mistake of saying to Brenda that gardening is not work it's play. She now constantly reminds me she is working in the house whilst I am playing in the garden

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    2. Hi Roger,
      Havent read all your replies theres so many, can you use iron sulphate if its going to be frosty, I remember years ago using a lawn sand, spreading by hand then there was a frost and it killed the grass as well.Thank you

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    3. Well done getting to the top oh unknowable one!
      I am surprised at your previous experience. I have never had any problems with frost and it has often occurred after spreading

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  2. You wouldn't like my sister's dog paying you a visit. Having lawn pride would cause problems.

    I don't want a mossy lawn but I love how it grows on the block on the shady side of our pond.

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    1. Yes, I have some very fine moss on none grass surfaces- and liverwort too. I once heard it said that if you stick a label in with the moss's latin name, everyone would admire the moss in your borders. I liked you moss pictures on your recent post!

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  3. So when you spread it, you have to tell the lawn that it's just fertilizer or the 'lawn police' come round. And when it kills the moss, just say 'Sorry guv, didn't see that coming.'
    My lawn is a worm friendly lawn, so I won't be able to use your iron phosphate. I use the fertilizer that is used on football pitches; it kills the moss, feeds the grass roots and feeds the weeds too. Makes it very easy to get the weeds out of the lawn though, they grow like triffids.

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    1. I like your humour Crystal! Hope it's humour and not sarcasm! (you can be sarcastic about the regulations!) It's certainly not illegal to use iron sulphate!
      Yes, most people use the 'three in one' these days, mosskiller, fertiliser and weed killer and it works well. Usually the moss-killer is part of the fertiliser and if it's not iron sulphate it is a very similar iron compound.
      I personally don't use the usual combined product because a) its expensive b) I don't want to apply fertiliser every time I have weed or moss c) its unsuitable for winter application d) I cannot 'follow the moss' or 'follow the weed' as I do when I spray.
      PS I doubt if your granular fertiliser combo is any kinder to the worms than the iron sulphate!

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    2. I bet you don't have molehills on your lawn Roger!

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    3. I agree. There won't be many moles under the lawn because there won't be a massive amount of earthworms after using iron sulphate. The moles will stick to the flower beds. It's one upside, I guess. I'd rather have the worms, myself.

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  4. Very interesting Roger - I had an old neighbour who used to spend all his gardening life caring for his lawn - the wife did everything else.
    I have an old dog who can't walk far and has to relieve himself on the lawn but when I get round to being able to sort out the mossy side of the lawn, I will certainly keep your blog in my mind.
    I do rake regularly, which seems to help a wee bit!

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    1. I admire your energy with the raking! If moss has not been already killed it is particularly hard work.
      Your neighbour's division of labour is not an uncommon one! I imagine if your dog walked as far as his garden he would be following the dog with a bucket of water to dilute his offerings. He would then have dark green blotches rather than dead grass!

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  5. Using an acidifier such as iron sulphate on a lawn makes the conditions much less inviting for worms. I was surprised to read this post. For a no-dig gardener, or indeed any wildlife gardener, I would have thought that this is rather defeating the object. And all just to get a ‘pretty’ lawn! Worms are great for the lawn, the soil and for attracting wildlife. There are about 27 species of worm in the UK but only three create worm casts at the surface of your lawn. As a no-dig gardener, I don’t need to tell you how worm tunnels benefit the soil by increasing organic breakdown and improving aeration and drainage. A lawn with worms is much healthier and will have fewer problems than a lawn without worms. This benefits the wider garden generally by attracting birds, especially blackbirds and thrushes, and hedgehogs, which help control snails.

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  6. I’ve followed your non digging blog right from the start, especially the wildlife and pest posts, as that is my subject, but I really didn’t get this one at all. I’m afraid I’m with Crystal on this (I think she was indeed being sarcastic) – I won’t be using your iron sulphate for a pretty lawn. I also agree with commenters, Anthony and Pam – I’d rather have the worms and their invaluable help with my crap drainage.

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  7. Like jason, I followed this blog since it started. this was because I too am a no dig gardener. The difference is I am also a wild life gardener and would not dream of using iron sulphate. The whole ethos of no dig gardening for me, is to work WITH nature, not to pick and choose the only bits that make gardening easy.

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  8. I seem to have walked into this one! I think I might have overstated the effect of iron sulphate on worms, it does NOT kill them but any fertilizer that acidifies the ground discourages them, just as lime encourages them. I intended to make the point with the picture of the worm cast that I DO have plenty of worms in my lawn. I love worms, I really do. My students would have told you that I was always going on about the wonderful things they do.
    Yes I do have loads of mole-hills in my lawn Christine, last year in particular it was a constant battle. In my first draft of this post I had a picture of one of my mole hills.
    Perhaps I might be forgiven, if I say that all my mowings are directly recycled with my mulch-mower and I do not use any other fertiliser other than iron sulphate. And my drainage is perfect!

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    1. Any wildlife gardener does not need to get TOLD what iron sulphate does to earthworms, we already know that! I suspect that many of your followers who do garden for wildlife were just very surprised at a non digger trying to discourage worms! It is positively counter-intuitive! Especially just for appearance sake. No-one said that soluble iron KILLS them, but your lawn certainly CANNOT be heaving with worms, despite the odd cast!

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    2. Let's all give him a break! As alluded to in earlier comments, it's a 'man thing'. They all have feet of clay (no pun intended) when it comes to a good looking lawn! :-)

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    3. If adding ferrous sulphate to the lawn just sends the worms to your borders to do their useful organic breakdown and irrigation, then maybe that's no bad thing. In any case, is it possible to add lime or some other alkaline substance to the ferrous sulphate to neutralise its acidity?

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  9. I just discovered this blog. Read a couple of posts and I have to say your blog is wonderful! Am your new follower.
    We love Madeira too and visited already 9 times, have also sweet memories of that Orchid garden.

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  10. Apologies for interruption in service, I unexpectedly have been out of action for the last three days and have not posted or replied to the hornet’s nest above me. Please excuse a generalised reply now. I only define myself as a ‘no dig gardener’. I do not commit myself to any single gardening philosophy. I have learnt by making numerous mistakes, the way I want to garden and for what it’s worth the purpose of my blog is to pass on something that might be useful.
    The wonderful thing about gardening is that there are so many different approaches individual to each gardener. I have found that my methods are generally encouraging to wildlife but I will not refrain from reporting what I actually do, even if is perceived as detrimental. In this case. I do not agree that using this fertilizer is disruptive to wildlife.
    I have just returned home to see the biggest molehill you could imagine, our velvet friend had no difficulty in finding his dinner! Last season I was pulling out a number of weed grasses (faffing about) and as I disturbed every weed an active little earthworm scurried away! As far as I am aware, iron sulphate has no appreciable effect on the ‘deep crawlers’ that are so beneficial - and by the way my lawn is perfectly drained. Grassland is known to be highly beneficial to soil structure, specially if it is cut quite long as I do. The fact that I leave grass cuttings on the surface returns organic matter and nutrients so little need for other fertilizers likely to encourage course grasses. Some gardeners have ecological lawns which I think can be quite wonderful but I am rather shocked to find a traditional English sward is seen as a bad thing!
    Although you have given me a bad time on this one, please continue to do so where it is justified. No comments on this blog are censored!

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  11. Ooow a can of worms here Roger ( well some one one had to say it ) I am really interested in this post as I have previously used the weed and feed formulars to improve poor quality lawns along with aereating, scarifying and regular cutting. I have always had worms in the lawn and brushed away their casts with a bessom.

    At my current home I have a very sandy soil which seems to have no shortage of moles!The orchard, a 5 acre paddock and one of my lawns suffer from moss and I would really like to improve them. This is for two reasons. firstly I want to improve the productivity of my land for my sheep who graze these areas and secondly because if left unchecked the moss will eventually overwhelm the grass.
    I accept that I may need to treat the soil in a way which deters my wormy friends for a while but like to think that once the moss is suppressed and the grass has recovered I can create an enviroment where the worms can return again. (not too fussed for the moles though) I would like to know what you or any of your readers would suggest to tackle this problem, chain harrow, scarrifier, or powders?

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    1. Hello Sue, what a big orchard! My expert gardening friend down the road does not control his moss with iron sulphate but works on the principle that if he feeds his lawn, the grass will outgrow the moss. I think this might be the best approach for your orchard or better iron sulphate and then general fertilizer.
      The fertilizer I think that would be best for our soil - I think yours is like mine as you are near - is yara mila, the fertilizer I posted about in September. I would use it at about 15gm a square metre. It is a little low on nitrogen for grass but will work out much cheaper than a regular lawn fertilizer and contains in addition to NPK trace elements and significantly magnesium and sulphur.
      link
      I like the idea of the harrow

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    2. Thanks Roger

      Its not my orchard that is a 5 acre padock, the padock is in addition to the orchard. You really should come round one day and do the horticultural equivalent of kicking my tyres.

      Will the yara mila be ok for sheep to graze on afterwards? My sheep graze every inch of grass round here. I was thinking of chain harrowing the 5 acre padock and using the elecrtic scarifyer on the lawn area but perhaps I should treat it first?

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  12. I would love to see your garden Sue! I will have a word with Harry when he comes to do your birdwatch pictures. I have already suggested to our mutual advisor Cathi that I might do a weed control project in your garden with a view to some joint posts.
    As to your lawn. I would definitely use iron sulphate to kill the moss before scarifying.
    As to the fertiliser in your paddock I would do all your other operations before spreading the fertiliser. I have recommended only a very light dressing of Yara Mila-which you can get from our near supplier East Riding Horticulture. It is just as safe to your animals as any other fertiliser including iron sulphate. As I have no experience of animal care and being cautious perhaps you might wait a couple of days.....any farmer will tell you whats best.
    Apologies everyone for our private conversation! Many of you would like Sue's blog, Chicken Whisperer whose address is in my sidebar

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  13. Great article Roger! After nearly breaking my back & shoulders last year lugging a 30L backpack sprayer around all weekend filled with iron sulphate, I'm going to try your throwing method. Looks much faster and therapeutic even!

    Ian

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    1. You will soon get the hang of it Ian. It is therapeutic and so quick!

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  14. People nowadays uses different types of pesticides for there purpose. As pest are increasing pest control is playing a crucial role to get a healthy and pest free life. There are many companies also that provide such good pest control services.
    cheap pest control gold coast | carpet cleaners gold coast

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    1. I do not agree that pests are increasing. Where they are, it is often where people apply insecticides and fungicides in an unnecessary way. Other than glyphosate I use very few pesticides and have very little pest and disease. I prefer natural control.
      Having said that with certain chemicals it might be best left to the professionals! (but not needed for iron sulphate!)

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  15. I have two very fine lawns (almost,but not quite, to bowling green standard)I would like to try sulphate of iron on my front,smaller 40 sq.metres, lawn. However, the lawn is bordered with ornamental blocks & I know from past experience that the slightest spillage whether applying dry by hand or in water turns hard surfaces orange. Any tips on how I might achieve this & is there any way to remove the orange stain which seems to last forever?

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    1. Yes anon, staining is a problem and any cleaning fluid I might suggest could make matters worse! I would be grateful if any reader has any suggestions for you - if I come across anything I will add a further reply!
      As to keeping your blocks clean perhaps you could cover with newspaper whilst you water on or scatter your iron sulphate

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    2. How to remove iron sulphate stain on stone and concrete. After my above reply I checked it out on the net. The good news is that the staining usually goes with time as it fades in the sun.
      Liquid soap seems to be recommended and citric acid available from some home brew suppliers seems to work. Lemon juice and vinegar are also mentioned. A good scrubbing or on some surfaces a power wash is suggested. It is best to tackle the stain as quickly as possible.
      My brother in law is quite happy with the stain on his concrete path and there are some interesting posts on the net of using iron sulphate as an attractive floor stain.

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  16. Thank you so much for your prompt reply. Because I have reasonably good lawns removing the orange stain by the methods described may in effect remove the stain but would almost certainly cause a lot of damage to my lawn. (Certainly if I jet washed) From past experience the iron sulphate solution just soaks through newspaper. Bit reluctant to apply by hand (overdosing) Vinegar would kill the grass.
    Forgive me I am not being negative but I realy do have beautiful lawns and any damage done would take a long time to rectify.
    Only just found your website. It's great. Sorry bit of a novice on internet. Am writing as ` Anonymous` because I don't know what else to do?
    Thanks for your help.

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    1. You have really got me thinking now anon.These are my observations
      If you use the powder method of application-
      a) I am often quite careless going over the recommended dose. The worse I get is a black patch of dead moss and the grass growing a little more slowly for a couple of weeks. I am proud of my lawn like you.
      b)Provided the iron sulphate powder is bone dry (refuse to buy it if it is not) and you spread it in completely dry conditions and brush it off your stone surfaces I reckon it will not stain.
      c) I would imagine by now your lawn is fairly moss free. Why not just carefully scatter over only the patches of moss?

      As to your anonymous nature, Anon....I am not very adapt about moving round blogs but I do have a g.mail address and a google identity. When I make a comment on a blogger blog my credentials automatically come up! magic I reckon!
      Why not just end your post with Jim or Fred or anything, even your real name!
      Roger

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  17. My front lawn has no moss. I intend using S of I purely to green up my grass. Let me try and explain how my lawn is situated.
    The lawn is bordered on its periphery by ornamental blocks. The grass is next to these blocks there is no garden border. On other side of blocks is my driveway. This is green ornamental slate chips (loose gravel). Once, by accident, I spilt some S of I, in dry form, on my drive. The stain has been there for some 3 years. You cannot spread dry S of I because some will invariably blow on to blocks & gravel. Although it may be possible to brush off blocks (doubtful) it is impossible to remove from gravel drive. Once rain falls unsightly orange stains will develop that last forever.
    I have a Miracle-Gro feeder. Do you think if I filled this up (500g) with S of I it would apply the correct dose? It would be painstaking but I could cover blocks with a plastic sheet. Reluctant to try it!
    Perhaps the best plan is to not use the stuff at all but I like the way it turns grass dark green.
    Forgive me this is not world shattering I am not so sad that I am that worried about it but I have enjoyed the chat.
    Maybe I should return to sulphate of ammonia for a green up? No orange stain problem there.
    Enjoy your garden.
    Bill C

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    1. I have enjoyed our chat too Bill, I think all said and done I would go for carefully watering it on with a rose on a can. I don't know about the Miracle Grow feeder, does it not come out with quite a squirt and I am not sure whether the iron sulphate is sufficiently soluble. Having said that I am not very familiar with garden centre contraptions and I would not rate my opinion!
      Glad to have your confirmation about the lovely green grass with iron sulphate, far better than the dark green from nitrogen fertilisers.

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  18. Dear Roger,

    Liverwort in deep crevices on a large area of granite Cobbles - will Iron Sulphate finish off my 'public enemy number one' ??? The base is sand on clay....so drainage cannot be improved beyond the gradient I have laid and I want to kill off, dig out and re-point with either strong mix cement or resin/sand so it cannot come back.

    Mike

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    1. You make it sound quite gothic Mike.
      Iron sulphate does kill liverwort but I find where there is a thick crust of liverwort it is not very effective. Perhaps a saturated solution drenched on will do the job. I understand vinegar near full strength also kills liverwort.(Don't know what it does to granite, probably nothing)
      Do you need to kill it to scrape it out from your cobbles?

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  19. hello, just wondered what to put on the moss in my lawn, which has daffodils in
    thank you

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    1. So has mine anon. If they are not through yet, apply by any of my methods.
      If through and you just scatter- as I have this very morning don't do it if the daffodil leaves are wet, it might stick and scorch.
      I find if leaves of adjacent leafy plants are dry there is never any scorch.
      The iron sulphate will be a treat for the daffs too!

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  20. Well done Mr Brook - as a retired farmer this is just my kind of gardening! We currently have a lawn full of moss (and yes we have lots of shade,poor drainage etc,etc) and I was wondering if having applied the Iron Sulphate, do you water it in?

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    1. Not surprised with a name like yours! Sorry PJ I could not resist!
      There is no need to water in, I just wait for the rain. It does need the rain to work and I sometimes notice the moss blackening some time after application and only after rainfall if it has been dry. Watering of course speeds up when it starts to work.
      I would not choose to apply in the middle of a drought but even this would be ok

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    2. Hello again Roger, don't worry about the pun on my name, my wife thinks it very funny - moss control that is. I'm quite impressed with the Iron Sulphate. I have about 1/4 acre of actual lawn all infested to varying degrees. Having time on my hands (we have'nt started lambing yet!) I decided to try both wet and dry application methods. 3 days ago I applied the 10gms rate by your favoured scattering method to 1/3 of the area and same rate to similar area by a spreader gadget I borrowed,and then lightly hosed in, and then yesterday applied the recommended 5 gm rate by watering can. Result:dry application is just starting to show an effect,but patchy, dry applic washed in looks better -ie more black moss, but the winner,for me, is the wet application, this area was turning black as I worked! and by next morning was allover evenly affected - I never thought I would be so pleased to see a black lawn! hopefully the other areas will eventually catch up. The product is definitely top value for money and thanks for introducing me to it. It certainly makes a change from rip-off chemicals sold in garden stores.

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    3. You certainly have been having fun PJ
      I used to find it very satisfying when I used to apply it dissolved in water in client’s gardens and seeing it’s immediate effect.
      These last two Winters have been wet and this one warm and I have found even as a regular user that the odd patch of potentially luxuriant sphagnum moss has appeared in the more shady places on the lawn and the grass paths. Three times since Christmas I have spent a happy relaxing half hour ‘spot’ treating my grass. Five minutes or so using a small plastic drainage tray which resides in my 25kg bag to scoop out a tinful of iron sulphate and making sure any lumps were crushed. Then a twenty minute wander around my acre garden treating the odd patch with a dry application.
      I must confess I frequently exceed my recommended rate quoted in my post.
      It went dry here several weeks ago and my last application just sat there without any effect in a rainless week but after steady rain one night the patches were delightfully black - and of course the grass breathed a sigh of relief!
      My lawn has been a particularly good dark green colour this Winter and I am very pleased with it It’s not just the iron sulphate but my fairly late application of general fertiliser mentioned in the late link I recently added at the end of this post.

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  21. I've got a largish part of my garden that I have done nothing to for years (and years) whilst I gradually cultivated the rest. I couldn't really decide what to do with this part, as it is totally covered in moss and is very wet. The garden is on a gentle slope and unfortunately the water comes down the hill and seems to rest in my garden. I'll have a go with the Sulphate of Iron and see what happens.
    Thanks
    Barbara

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    1. It will help with the moss but not with the water Barbara.
      Sorry I have not replied before, I had missed it in my e mail reminder. I have such a brilliant filter, a lot of spam comes in under the title anonymous these days that I can just ignore as it does not get through. Your message of course is welcome.
      It might surprise you but sometimes I think moss looks quite nice, but not in my lawn!

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  22. Is sulphate of iron harmful to dogs??
    Many thanks
    Declan

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    1. Don't spray them, their fur goes black!
      Sorry Declan just joking it's not a toxic material! I get it on my hands every time I spread it.

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  23. Hi Roger, Interesting blog. I have a terrible lawn, full of moss and weeds. I am aiming at a nice green grassy lawn this year. I applied one of the expensive rip offs last week to kill the moss. I wish I'd seen your blog before. I cut the grass today then spent hours with my electric scarifier. I was amazed at the amount of dead grass and moss it took out. My so called lawn looks a complete mess now, with bare and brown patches where the moss had taken over. I may need to apply some grass seed to some patches, I'll see how it goes, but it can only get better, right ? Would you suggest I use the sulphate of iron as a fertiliser for the grass at this stage and also as a cure and remedy to stop the dreaded moss invasion ? or should I apply something else to recover the grass. Your advice would be appreciated. Thanks and carry on the good work along with your amusing wit :)
    Sandra

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    1. Hi Sandra, sorry I had not replied, I get so many alert-e-mails that are under anonymous that are spam - and which google efficiently filters out -that I don't even read them. So I miss genuine comments such as yours!
      Now is an ideal time to get your grass going again with general fertiliser. Put lawn fertiliser into my search box and read how a good general fertiliser will do the job!
      Put Sandra in as your name to get a prompt reply

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    2. whoops that's not clear Sandra, you don't need to put Sandra in 'search this blog'

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  24. Hi Roger. You have me totally converted to iron as a moss killer. After the wet winter we've just had my back lawn was completely infested with it. Thankfully, after finding your blog and following your advice, it's now completely gone.

    However, I have a major problem on my front lawn. It's covered in Speedwell!

    I've never had this problem before and can only assume that I've managed to spread what little there was all over the place by leaving the grass box off last summer. I have a 10 bladed cylinder mower that chops up the clippings into very small pieces and it makes a great mulch but I think I need to re-think that strategy. Speedwell is Everywhere.

    I've tried to kill it using Verdone Extra and it's now turning a paler colour but boy does it look unsightly.

    Would you happen to know if applying a dose of iron would help? I need to feed the front lawn but am wary of also feeding the speedwell.

    Any advice would be gratefully received.

    Thanks.

    Peter

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  25. Not an easy one Peter
    The RHS say that slender speedwell is resistant to all lawn weedkillers. Don't know which speedwell you have! I actually like speedwell although I have none in my lawn. I sometimes use a professional weedkiller that contains chlorpyralid and triclopyr. The nearest to this on the amateur market is your verdone extra which I would have thought controlled most speedwells.
    It does not contain triclopyr which is the active ingredient of SBK brushwood killer which the RHS say is only suitable for using to control weeds in coarse grass. Nor do I know whether triclopyr specifically is any good against speedwell but I suspect it is.
    What I do find with my equivalent of verdone extra is that the active ingredients are slower to act (although more effective) than popular lawn weedkllers. You might find yours has been more successful than you think. It will certainly need 2 or 3 applications at six week intervals or so to get rid of it. Continue to let your mowings fly so that any chemical is recycled to the lawn and does not contaminate a compost heap.
    Its a good time to feed the lawn now and iron sulphate also being a nutrient will only do good. Read my advice to Sandra above about fertiliser

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  26. Hi Roger,
    I just came across your page, very entertaining and useful. I bought a bungalow in the country a couple of years ago and the lawn, if you can call it that, has been neglected. I went to the garden centre to get sulphate of iron and found the price out of the question, I phoned the local agri-store (farmers co-op ) they quoted a price of twelve euros for a 25kg bag, I was very pleased.
    7 A.M. Monday morning and I started to spray using an old CP3 sprayer, it did the job very well but I di not think I had got all the moss, 7 A.M. Tuesday morning I did the lawn again, now the moss has changed colour.
    On Saturday weather permitting I am going to scarify, My question is how soon can I scatter some lawn seed to cover all the bare patches.
    Thanks,
    Paul

    ReplyDelete
    Replies
    1. That is cheap! Hope it did not clog your sprayer.
      Sow straight away whilst their is some moisture around and it is getting warmer now. Scratch it in with your rake or scarifier,

      Delete
  27. Joseph Whitehead26 April 2014 at 05:19

    I'm curious about that sulfur-in-air claim. It makes sense for areas that don't naturally have a lot of sulfur in the water. However, I'm living in Colorado Springs and... we don't exactly have that problem. :D
    Modern population levels put out at least enough H2S to counter any 'reduction' of sulfur in the air from scrubbers at power plants. Remember: Those power plants didn't exist before modern times and there was plenty of sulfur in soil.

    It's amazing to see how much almost 100% pure artificial gypsum those coal plants' scrubbers make, though! All the calcium and sulfur your home's walls could ever want! Now you know why drywall is so cheap compared to some other similar materials...

    ReplyDelete
  28. I am not quite sure what you are talking about Joseph but I think you are on about my suggestion that the sulphur in iron sulphate provides this nutrient to the benefit of plants.
    Here in the UK it is believed by farmers and gardeners that there is plenty of sulphur in the soil from our former coal fired industries. This is now in doubt and like some other parts of the world there are some parts where sulphur is deficient. Gardeners have inadvertently been fertilising with sulphur when they have, for example, used nitrogen fertiliser such as sulphate of ammonia (Also good for lawns!) Farmers don't traditionally use sulphates and sulphur containing compounds are now sometimes added - including sulphates! to combat sulphur deficiency.
    Of course sulphur is contained naturally in the soil. I am constantly telling gardeners not to use any fertiliser at all to soil in 'natural' garden situations.

    ReplyDelete
  29. I have been enthusiastically following your aricles for some weeks.
    I have regularly treated my half acre plus of lawn in the past with applications of Iron sulphate using a watering can. It was quite hard work. For the past few years the lawn has been neglected and with the wet winter the moss had taken over. I used your dry scatter method to great effect, and much less effort, but some large black areas. I then scarified and raked to remove most of the dead moss. I was left with some large bare patches which I reseeded 2 weeks ago and also scattered seed over all areas. I have watered regularly and the seed has generated fairly well but is growing slowly presumably due to the iron sulphate. The 'old' grass is now getting long and a cut is overdue. How soon can I fertilise the new grass with sulphate of ammonia, perhaps with some potash, to speed up the new growth in preparation for a first cut with the rotary mower?
    Octagenarian

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    Replies
    1. Thanks for your interesting question Octo!
      Glad to hear the iron sulphate has been successful. I expect on a half an acre you will have soon got into my scatter approach and will be now skilled at drifting the fine powder into exactly the right place on the air. I find it very satisfying and speedy!
      I am a little puzzled by your mowing policy. If I have cause to re seed any patches I just carry on mowing at my normal frequency. Like you, I use a rotary mower and as I never have it set at the closest cut I just ignore the fact that there is new grass sown. I might just set it slightly higher for a couple of cuts?
      Long grass shading your new seedling grass will inhibit growth far more than your mower going over it or any inhibition by the iron sulphate that only occurs anyway via the initial scattering over the leaves.
      I do find grass from seed is initially quite slow but I did resow a patch - don't ask - at the end of March but could scarcely find it now in late June.
      Yes you can certainly fertilise with sulphate of ammonia, if you want potash too I advice using a general fertiliser as described in the link I recently added to the bottom of the this post

      Delete
    2. Thanks - advice taken!
      Any advice on clearing or inhibiting ants from lawns would be welcome. Clearing ant hills is quite a tiresome task.

      Delete
    3. Unless it's serious leave it alone! On our sandy soils around here it can be a problem. Not this Spring it is so wet!
      Brenda has recently had ants coming out of cracks from under the tiles in the kitchen and ant powder was very successful!
      The RHS site gives good but 'guarded' advice.

      Delete
  30. Hi Roger
    I found your original article and comments from your followers very interesting.
    I had a problem with my lawn since it had a lot of moss and weeds and I then applied lawn sand too liberally in a number of areas to the point where some patches of grass seem to be dead or near dead. Some small green shoots are appearing in some areas however overall I feel like I have made a significant error.
    I have been told by the manufacturer that it is possible to kill the grass however they believe overseeding / reseeding is possible after about 3 weeks when the ferrous sulphate has washed down.
    I also think that I should apply some weedkiller to the lawn first since seedlings presumably could be harmed by the weed killer.
    Do you have any feel for grass root survival, one of my contacts thinks that the roots can usually survive even if the leaves are burnt off. How long can it take before the roots respond to show they have survived?
    Any help would be most welcome.
    AW - a very worried lawn owner

    ReplyDelete
  31. does iron sulphate kill weeds? I do not want it to.I am carefully cultivating clover,vetch,daisies etc for insects but do have avery bad moss problem

    ReplyDelete
  32. It is sometimes claimed that iron sulphate kills weeds. I do not agree and the most it will ever do will blacken them before they carry on vigorously growing.
    If you use the powder application method I don't expect it to even scorch if you apply it when the leaves are dry (or immediately before heavy rain that will wash it in)

    ReplyDelete
  33. Would recommend but do not apply when the grass is wet I have used for 20 years now.
    One comment regarding feeding the grass (but a good feed) I also us more if I have a small growth of clover as the grass will kill the clover if feed in a local area

    ReplyDelete
    Replies
    1. Not sure anon why you have reservations about grass being wet. I often apply it when wet
      Yes you might be right that feeding the grass with a nitrogen containing fertiliser encourages grass growth at the expense of clover - but it won't get rid of it.

      Delete
  34. Hi,

    Been reading your great blog for a while now :)
    Thanks for sharing your experience!

    Question for you from abroad...(France)
    Here in France it seems that no one recommends iron sulphate, quite the opposite to UK actually.
    All I have read is an aversion to the product based on the fact that iron sulphate will work weel in the short term by killing moss but will make matter worse in the near term by raising acidity and therefore giving moss better conditions to thrive ...
    Oddly enough, I have never read anything like this in the UK where most serious gardeners seem to swear about it.
    I was wondering what your views might be on this?

    Vincent







    ReplyDelete
    Replies
    1. Hi Vincent,
      Sulphates do acidify the soil slightly although the fairly low application rate of iron sulphate will mean that the effect is small. Many of us like to lower the acidity slightly as this encourages the finer grasses such as fescues - which I love. I am not a fan of ryegrass that tends to like it more of a neutral level- i.e. a higher pH..
      It is rather a myth about moss being more common when acid. If pH effects mosses presence it is at extremes of the spectrum- that is very acid pH<6 or too alkaline pH>7

      Interesting how gardening cultures vary with countries. Partly due perhaps to different Gardening gurus!

      Delete
    2. I have had recent correspondence with a reader who does already have acid soil and applies lime with his iron sulphate. I have no experience of this personally but assume it would be ok, although as I say I think generally the acidifying effect of sulphate is not causing a problem

      Delete
  35. Great, thanks for that Roger :)

    My lawn needs lots of TLC, which order would you advise for these operations:

    - Scarification, weed killers, iron sulphate, fertilisers, over seeding, top soil...

    Thanks again for your great blog!

    Vincent

    ReplyDelete
  36. Selective weed killer now - its not too late despite what the books say especially in your warmer climate and fertiliser now, light dressing
    oh yes you can also put on the iron sulphate!

    next week rake in any top soil to fill undulations and sow into soil and generally spread about-
    you can scarify now too but it will be hard work if moss not dead yet
    I could be persuaded to do all the operations on the same day, but no point scarifying out moss yet

    ReplyDelete
  37. Wow so all in one huh ;)
    Would have thought that all those chemicals simultaneously would have caused some side effects.

    Vincent

    ReplyDelete
    Replies
    1. In effect its no different to the three in one mosskill, feed and weed which most other gardeners use!
      I am only trying to speed you up!

      Delete
  38. Hi just started using suphate of iron as a moss killer on my lawn and had great results after 1st application hope to be moss free for summer.

    ReplyDelete
    Replies
    1. It certainly does what it 'says on the tin' although as explained it says nothing on the tin as they don"t want you to know! -whoops there are so many comments now I might have made that joke before!
      Remember Brian if there are serious causes of moss you will have to continue perhaps every six months

      Delete
  39. Hi, I have a large grass area in my garden. I have tried the flinging method of applying the iron sulphate but fear I have over applied in places and under others. Therefore I intend on going down the sprayer route. I would also like to apply verdone to kill the weeds. My question is do you know if it is possible to mix the two together and ply in one application? Any experience of this?

    I then intend to scarify and reseed

    ReplyDelete
    Replies
    1. I would be very surprised if you have applied too much Stephanie. Despite my pretence of responsibility in my article I frequently double and perhaps treble my 'fling' where I see a particularly thick bit of moss- usually the edge of the grass where my plants have given summer shade! That would of course mean that if you had calculated your total dose more carefully than I actually do for the whole area some turf would get less than it should!

      I have been flinging my iron sulphate so long now that I just go to my sack, break up any lumps - it is best if it is really dry and powdery but it does not always come from the supplier like that - put it in some convenient container, use it up and come back for some more!
      There you have got me to destroy anything I might have left of any reputation.

      There seem to be a few different verdones! If it is just the lawn weedkiller ordinary verdone or verdone extra then certainly mix your iron sulphate with it providing you are applying your dilute solution with a can and rose. Not with a sprayer though as it tends to clog with undissolved iron sulphate

      Delete
    2. Hi roger, I am one week into my lawn project. I mixed iron sulphate with warm water to dissolve, poured it into a sprayer, along with verdone and more water. It look a good hour if not longer to do the whole of my lawn but hopefully worth it. The moss is now black and the weeds starting to blacken. Some still seem untouched and have noticed some areas of moss are blacker than others. Can you recommend of what my next step should be? I intend on re-seeding at some point. Should I out the black patches now, leave it a couple of weeks or not bother at all? My lawn also has a lot of thatch so feel that by leaving it,I would be adding to the likeliness of it returning sooner rather than later. It looks a right old mess to be honest, already getting grief from my other half!!!

      Delete
    3. I suggest you apply a little more - risk flinging it?- to the unkilled areas. I find that some of the thicker mosses like sphagnum need a higher dose.
      Re seed anytime through the summer although as it gets hotter and drier, dry spells impede germination. For what its worth I have been flinging a little fine grass seed and a throw and grow flower mixture on a rough patch of weed free soil today!
      Your other half should be grateful for all you efforts.
      As in my lawn I am 'on top' of the moss situation I never bother scarifying the dead moss out. If you have thatch too it might be worth your while scarifying but not essential

      Delete
  40. Thanks for your reply Roger. I'll give it a try! I have read somewhere to avoid clogging up the sprayer, mix it in a separate container and then transfer it, the non-dissolved particles 'should' stay in the original container if poured carefully.

    Fingers crossed I'll have a moss and weed free lawn by the summer!

    ReplyDelete
  41. Love your post Roger, as an Ex Greenkeeper I agree with all you state.
    There is quite a bit of talk of dogs causing problems on lawns, it is only the female that causes the problems and it is the first wee of the day that is the culprit.
    This is due to the build-up of hormones in the urine during the night that scorches off the grass, if you know where she has been you can water the patch soon after she has been and this will dilute the urine and not cause a problem.
    Back to the Sulphate, I mix mine with sharpe sand for the only reason to avoid over dosing and patches.

    ReplyDelete
    Replies
    1. Thank you for your encouraging words anon. It's great to hear from a professional. We use to run greenskeepers courses at my old college and the students were the nicest we had.
      Thanks for the info about bitches! This post is starting to collect useful information from such as yourself.I write about fertiliser scorch which can be found in the theme column under lawn

      Delete
  42. Hi Roger, Im interested to know if you have heard of a mix of sulphate of iron, ammonia and silver sand (I require the quantities) that can be used for getting rid of moss, weeds and feeding the lawn. I used to have the 'recipe' but can't find it now. My lawn has lots of moss, dandelions and flat broadleaf weeds. Its a real mess, uncared for due to illness :-(

    ReplyDelete
    Replies
    1. Sorry anon , only just seen your comment!
      The important thing is that your sulphate of iron should go on at about a quarter of an ounce a square yard and sulphate of ammonia at about an ounce per square yard - in old money!
      The amount of sand is insignificant as you will be applying far too little of it to have any direct effect on your soil. The sand is just to aid you spread it. Perhaps between half and one pound a square yard.
      This mix will be next to useless against weeds. It will make them grow better!
      Try Stephanie's verdone as a spray or watered on! Stephanie is just above you!

      Delete
    2. Thank you Roger, for your reply. No worries that you didn't spot my post, I've not been able to pick up any sulphate of iron locally (the big stores with garden sections don't seem to be stocking it - some carry only an 'urban' range this year!!). I could try the verdone or perhaps use the iron sulphate first, as you describe elsewhere, and then mix I mentioned to 'continue through and brighten up'. My uncle (95 years old now) swears by his mix and is still an avid gardener - I doubt his lawn has ever been in anywhere as bad a condition as mine!! Have enjoyed reading your blog and found it interesting and helpful. Don't stop! Jeannie

      Delete
    3. Thanks for your nice comments Jeannie and good to know your name!

      Delete
    4. hi anon I think I may be able to help with your quantities I got recipe from a greenkeeper a few years ago and I use it all the time with superb resuts 1 kg of iron sulphate. 2kg of sulphate of ammonia and 3kg of fine sand all mixed together will all you will ever need for a fine lawn hope this helps

      Delete
    5. Thanks for this . I guess that amount would be for a hundred square metres?

      Delete
  43. Thanks for your blog Roger.

    I will shortly be obtaining pure Ferrous Sulphate and wonder if using a mechanical spreader would obtain the desired result of killing my Dandelions and broadleaf weeds. I assume adding 50% sand would be recommended. Would this method of application achieve the desired result?

    Thanks
    Jim

    ReplyDelete
    Replies
    1. I am a bit pathetic with mechanical things Jim, and avoid using them wherever possible so I have no direct experience spreading iron sulphate by this means. I see no reason why not as long as the equipment spreads powders evenly and handles small doses accurately.
      It sometimes is a bit lumpy in the bag - it should not be but suppliers might still try to sell it. I imagine if their are lumps it might be difficult with a spreader. You will need to crunch up the lumps
      I would use at least three parts sand to bulk it up - although if any readers have experience with iron sulphate direct via a spreader please let me know.
      As I have hinted I think it is actually pretty useless against dandelions. At best it will check them.
      I frequently let my drifted iron sulphate drift on my borders and provided the plant leaves are absolutely dry there is no scorch whatsoever.

      Delete
    2. Thanks to Anon (15th May) for posting the quantities of the lawn 'mix'. I have recently acquired the sulphate of iron and, after treating the moss-only areas, will do the whole lawn with iron, ammonia and sand. As roger commented earlier, the sand will aid an even spread. Roger, it is not long since I have begun looking after my rather neglected garden myself and it has been a great help to follow you since I came across your site by googling 'Sulphate of Iron'. Reading previous posts, it seems there are other gardening topics that you cover elsewhere. How do I access the rest of your site? (By the way I reply as anonymous because I don't use/have another profile). Jeannie

      Delete
    3. LINKS Jeannie Links! All those coloured words you just left click them to go there. Wonderful things I only discovered myself when I started blogging three years ago.. (Some coloured writing is just a title or something but links are 'live' and take you there)
      You might like to try the 'you might like these ' at the end of each post. Just click the little picture.
      I recently started grouping 'themes'. They are in the right hand column at the top of the blog. You just click these too. The top ten posts in the right hand column you just click too.
      As you come in on your comments as anonymous then just identify yourself as Jeannie
      Why not click 'members' and become one!

      Delete
  44. I have just discovered the benefits of iron sulphate myself owing to rather severe iron chlorosis in my own small garden, mainly on the serviceberries and deciduous hollies. I have had two application of iron sulphate already, coupled with incorporation of cow manure in the soil surrounding the hollies. Already there is marked improvement. The leaves have ceased yellowing and some are already turning green. Unfortunately, the only iron sulphate that I could find was incorporated in a mixture for moss control, to which had been added fertilizer for grass. I was desperate. So I decided to use it all the same. I am now searching for just iron sulphate and am having a hard time find any. (I just discovered your blog while looking for that plain iron sulphate. It is quite interesting and I will be visiting often as yours is the type of gardening that I do too. Thanks for sharing your knowledge and insights!)

    ReplyDelete
    Replies
    1. I expect the extra nitrogen and the cow manure will contribute to the greening. You should be ok with all that!
      Sometimes hollies go rather chlorotic before they make new leaves you can read about holly in my post on holly - its under the theme column as Christmas plants
      Welcome to the blog Gene!

      Delete
  45. Just found your blog Roger, while searching for info on using sulphate of iron as a moss killer.
    Some very interesting reading, thank you.
    I discovered a 25 Kilo bag of sulphate of iron hiding in the shed last week and decided to give it a try as I had run out of my usual feed - weed & moss control.
    I dissolved approx 65g in a 14 litre watering can and applied the solution to the lawn which is 8m x 2.8m. I needed three full watering cans to cover the area.
    After 10 - 15 minutes the moss had turned brown and the next morning it was black and very dead looking. That was about three days ago and I think the grass is slightly greener but not really sure on that point, though I'm definitely pleased with the results on the moss.
    BTW there had been very little rainfall for a week or two before I treated the lawn and only a very light shower or two since.
    I wasn't sure what strength of solution to use but it seems I may have got lucky as far as killing the moss is concerned.
    Do you have any advice on using this method, including the strength of solution for greening up the grass?
    Gene, you can buy iron sulphate on Amazon. Search for Ferrous Sulphate.

    ReplyDelete
    Replies
    1. It takes a while for the grass to really green up Bill although you do get an initial slight darkening.
      I recommend a quarter ounce a square yard for just greening the grass and a little stronger if the moss is bad.
      You can't really dissolve too much iron sulphate in water to do any harm to the grass provided that you keep the overall amount at not more than about half an ounce a square yard.

      Delete
  46. Wow, much cheaper than branded moss killers, but very effective. Added bonus the grass looked golf course green after application which was a doddle.

    ReplyDelete
    Replies
    1. Well done sneaking your ad on, but how could I refuse an endorsement from a golf course?

      Delete
  47. Roger I have applied the IoS using the watering can method the moss on my lawns went black and after 5 days I scarified it, wondering if you can tell me how long after using IoS that I can put grass seed on?

    ReplyDelete
  48. Straight away - or if you are feeling cautious a couple of days!

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  49. Roger I have applied the IoS using the watering can method the moss on my lawns went black and after 5 days I scarified it, wondering if you can tell me how long after using IoS that I can put grass seed on?

    ReplyDelete
  50. Hello, would IOS harm rabbits. Their run has a lot of moss growing in it. How soon after could they eat the grass? Thanks

    ReplyDelete
    Replies
    1. The grass may taste a bit bitter and it might increase their haemoglobin and they go rusty if you spray them!
      Just joking anon. You can buy tablets for your own medication!

      Delete
  51. Very many thanks for sharing your experience and expertise. As a new 'retiree' I now have the time to focus on my lawn. I have just sprayed IS for the first time (can no longer afford weed and kill fertisisers) and I now await the results. Please carry on. John

    ReplyDelete
  52. I have a pond in the middle of my lawn. Would iron sulphate be toxic to pond life?

    ReplyDelete
    Replies
    1. So have I anon!
      I try not to let it drift into my pond but more because it might stimulate green algal growth.
      You might read about some scientists wanting to seed the oceans!
      I would suggest that you are unlikely to have any problems with careful use and that you would need to pour in very large quantities to adversely to be toxic

      Delete
    2. Wow, that was a quick response. Thank you so much. Much appreciated.

      Delete
  53. Hello Roger. I just want to say Thank You so much. Your advice has been so useful for me and I have saved an load of money by following your wise words. My lawn was looking a right mess. The mower had been spreading the moss spores and the moss was in lines on the lawn. What a fantastic solution. It is now looking like I care about the lawn. If I lived closer, I'd buy you a beer!!
    Thanks again
    Phil (Norfolk)

    ReplyDelete
  54. Comments like yours make it all worth while Phil
    Moss spores are everywhere Phil. It's more likely that for some reason the grass under the wheels has suffered in some way and if soil is vacant and it is wet moss grows!
    Cheers

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