Yes you can.
|One of the better bits of my lawn|
Essentially there is no difference between a lawn fertilizer and a normal fertilizer. If your fertilizer is suitable for general purpose use in your garden it is suitable for your lawn. A granular fertilizer is no more or less likely to scorch than normal rapid release lawn fertilizer. Scorch is easily avoided by applying fertilizer immediately before reasonably heavy rain.
Should I use three-in-one?
The ‘rest of the world’ seems to use this combination of fertilizer, moss killer and weedkiller. Not me. The moss killer is usually iron sulphate and is itself a valuable lawn nutrient. I prefer to fertilize, moss kill or weed kill as a separate operation where and when and if I need to. Using three in one is perfectly sound practice but count me out.
Do I need to use a fertilizer spreader?
No. It might be convenient for professionals to use a high quality spreader on a large scale but in the home garden with a little practice you can spread very evenly. Sometimes a badly adjusted spreader can cause more scorching than hand spreading! I tend to rather energetically fling my fertilizer. This would be inappropriate with ‘three in one’ as any flying on the borders might damage the plants!
How often should I fertilize my lawn and how much should I use?
This is a little beyond the scope of my article today. Once a year in Spring will be enough for most people although there is some merit in applying smaller doses but more often. If you box off your mowings thereby taking nutrients away there will be more need to fertilize. I mulch mow and take the unfashionable view that too much nutrient means much more mowing! For the record I applied 15gm/sq.meter of 20:10:10 agricultural fertilizer last month. It was my first fertilizer application in two years.
Which fertilizer should I use to feed my lawn?
‘Three in one’ purchased at a garden centre is relatively expensive but for a small lawn lawn the high cost is probably insignificant, For a large lawn the cost can be considerable. I have previously written about buying a 25kg bag of general fertilizer and using it generally! If you have a very big lawn you can achieve the same economy of scale by buying 25kg bags of sports turf fertilizer from a professional horticultural supplier. (Do not be persuaded to buy their amateur products, some suppliers on the net have an expensive amateur section. Your money is as good as that of any professional!)
I have prepared a table of the relative costs of fertilizers you might sensibly use on your lawn, I have related the rate of application to the one recommended on a packet of ‘three-in-one’ that I examined at a garden centre. I have adjusted the rate of application of each fertilizer to provide the same amount of the most significant nutrient, nitrogen to that of the garden centre product. This will often in practice mean that more phosphate and potash will be provided by the fertilizer than from a normal spring/summer lawn fertilizer. For my sandy soil this suits me fine.
I have assumed for my calculation that you have sought out 25kg bags at a keen price. My figures are heavily rounded.
Cost of fertilizer for a 1000 square meter of lawn
20:10:10 20gm/sq.m £20
sulphate of ammonia 20gm/sq.m £25
13:13:20 30gm/sq.m £30
Yaramila complex 30gm/sq.m £35
Professional sports turf fertilizer £35
Growmore 60gm/sq.m £45
Gardencentre 3 in 1 30gm/sq.m £100
The 13:13:20 was the general fertilizer recently applied at 12.5gm/sq.m by my expert friend Peter Williams.
I sometimes recommend sulphate of ammonia even though it does not contain phosphate and potash. On some soils it’s sulphur content may be very beneficial.
The garden centre ‘three in one’ was for sale in 7kg bags at £20. Its analysis was 14:2:4
Yaramila complex is the complete all nutrient fertilizer I generally use and it’s NPK content is 12:11:18.
A small trial.
In the interests of bloggery I added a few variations to my fertilizer application. Most of the lawn was fed in mid August with 20:10:10 at 15 gram per square meter (a very low rate but suitable for late summer). For a hundred square meters I doubled this amount and for a further hundred square meter trebled it. The anticipated rain arrived and there was zero scorching on all treatments. Unfortunately it then turned very dry and I cannot therefore show you pictures of an amazing green lawn! I think I can look forward to more benefits of the nutrients when it turns wet. The lawn has been improved by all the three rates of application with at the present time little discernible difference between the three rates. There has been a distinct increase in the need for mowing!
It is too late now in mid September to apply the high levels of nitrogen given by the rates of application in the table. I would not use 20:10:10 until March although low rates of an even balanced fertilizer like growmore would be alright. I think for most lawns in the UK autumn fertilization is of limited value.
A few days after fertilizing and when it had turned dry I marked out two squares of one square meter each and applied 20:10:10 and Yaramila complex both at the very high rates of sixty gram per square meter. This was deliberately done when the surface was dry and rain was not anticipated. It was a very hot spell and it did not rain for four days.The August dews were heavy. I imagine dews in the absence of rain are likely to increase the danger of scorching. You can see from the picture that the 20:10:10 did scorch.The Yaramila did not. Although the scorch has now grown out - after a month - and the grass is again green my demonstration does show that the rapid release of nitrogen from 20:10:10 can cause a problem. (I recently described it as lethal in inexperienced hands). Although the Yaramila would have also added a lot of nitrogen it would seem that its formulation does release its nutrients more gently.
|A very high rate of fertilizer|
|The high nitrate in a heavy dose of 20:10:10 did scorch|
|The two dark squares are one month after applying heavy doses of yaramila and 20:10:10.|
Supplementary notes for lawn nerds
I was prompted to feed my lawn because patches of red thread disease had appeared and was getting worse with heavy autumn dew and very dry soil. This is a disease of underfed closely cut lawns. On the other hand beware using excessive nitrogen rich lawn fertilizer as this predisposes the grass to a worse infection, fusarium! You can’t win!
|Red thread disease. Now, four weeks later we have had a period of wet weather. I am pleased to report the fine grasses are making strong new growth|
I have ignored in this review the use of much more expensive slow release fertilizers which can give a lovely green sward for very long periods.
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