Monday, 17 December 2018

What to do with Autumn leaves


Freshly fallen leaves can look rather nice
My own instincts are to keep nature’s gift of organic matter wherever it comes from. I am silly this way and cannot really justify walking the length of the garden to deposit some meagre organic waste from the kitchen as I regularly do.
I am not so dedicated as to bag up autumn leaves to wither away to next to nothing over several years but I do like to think I do keep most natural leafy provision. 

No need to worry about these hosta and pulmanaria
That is not to say Autumn leaves are not a considerable nuisance  and in certain cases their cover might damage our plants - this is much overrated.  Today I try to consider the problem of disposal and to evaluate the benefits of recycling. Not for me the municipal organic green bin method (arguably for many the obvious solution). I have written about this before how I am too much a Scrooge to give my manna away.


My garden receives an abundance of leaves. Not only does it contain a wealth of shrubs and small trees but it is on the windward side of a small wood. No point in too much of an early sweep up, as soon as the wind blows there will be more. On the other hand I have ample large borders where the leaves can permanently lie. They help hide the weeds!

A temporary sweep into the edge but there will be more. In due course pull them more to the middle 
It is probably best to completely remove leaves from a narrow border like this - and move them elsewhere
However laid back untidy a person you are you will probably need to do some sweeping, raking or blowing. It’s all very well and hugely beneficial to let leaves permanently lie but some will collect on the lawn or hard surfaces, lie in depressions and edges or in the case of large leaves smother your plants.

My best investment ever
I used to think my wonderful cheap plastic scarifier was my personal secret. Now I discover all the world has one. Even  the wit who recently demonstrated how to rake up Finland’s dense forest had one.
It’s a wonderful tool to sweep up the leaves. It flicks over borders, clears out lawn edges and cleans up the lawn.


Leaves on lawns can merely be mown with a rotary mower. You will need several passes to shred the weeds or you can mow on a few separate occasions. Come to think of it you can box them away.

I admit to be lucky and in my case most leaves can be left or raked onto borders and permanently parked as a mulch.

Leaves as a mulch


It is worthwhile to leave leaves on the surface and as they decay improve soil structure. In ecological terms it would sometimes be better if the organic debris would accumulate on the soil surface but this is usually thwarted by the worms. Usually a good thing as untidy leaves will be gone well before next Summer and a greater depth of soil will benefit. If you want an organic layer it might be better to gather up piles of leaves in compost bins and leave them two or three years to decay before topping up your soil.

Even over gravel I find this light covering of small leaves is gone by late Spring

Every Winter I need to use a strong metal lawn scarifier to drag out copious pond weed and Autumn leaves

Leaves as a nutrient source


In practical terms I would say forget it. Most leaves are carbon rich and low in nitrogen. Indeed as a consequence fresh leaves can deplete the soil of nitrogen as they decay. Such loss is only temporary and all nutrients eventually become available. I suggest leaves are in practice irrelevant as to whether you do or do not need to apply fertiliser to your soil.
Autumn leaves actually do vary hugely in how much nutrient they contain. Some woody plants have evolved to extract leaf nutrients before leaf fall and stash them away. Others merely reflect how much nutrient the plant extracted from the soil.
Some leaves are reputed to be acid. This might be so but any (good or bad) acid layer is shallow and has a very low overall acidifying capacity.

Composting leaves
No need for permanent compost heaps in my cemetery gardens - nor in my own
Because of their high carbon nitrogen ratio and their tough lignin and cellulose rich content leaves are very slow to decay. Not a bad thing in the ground but a long wait in a bin.
One solution is to mix it with a substantial and greater proportion of the softer more nitrogen rich debris you normally use in making compost. 
It might seem obvious to accelerate composting with nitrogen fertiliser. I might have done so myself before I wrote my little read post which reported overlooked research saying this does not work.

My friend Peter Williams creates the bulky matter for his homemade seed and potting composts by composting leaves 50/50 with lawn mowings. When later making his potting compost he adds slow release fertiliser and lime as described in the link below.

Are there any other uses for fallen leaves?
I await your suggestions!


Clumps of bulbs were already sprouting in their pots when I planted them in soil filled to the top
Brenda has been complaining that Peter’s display of containerised  Spring bulbs puts mine in the shade. I have in consequence splashed out on daffodils, tulips and lilies from Parker’s Wholesale. I have planted up some very large plastic containers and a few unfortunately very heavy old ceramic pots.
These are potentially too heavy for an old man like me to shift around.
I note many gardeners perhaps foolishly economise on compost by using light inert filler at the base of their large pots. This year I am using leaves to lighten my load. Of course they will sink somewhat and I am preparing a post to show how it works out.



Clearly leaves bring benefits of mulching. For a few years my dahlias that overwinter in the ground have benefited from mulch's insulation. I partially cut the dahlias back after first heavy frosting and heavily sweep leaves over and amongst the debris. As a warm overcoat I like to think that it helps.

It is perhaps with reluctance that I might mention that for those of you who still Autumn dig your vegetable garden you can dig your leaves in

Link
If anyone is intrigued with my comment about nitrogen fertiliser and compost read my post here

11 comments:

  1. I've got a few sycamore which have had tar spot for years. Doesn't seem to bother them. However I've never put the leaves in my leaf mould "bin" (chicken wire held together by tie wraps pinned to the ground) I've just left them to blow away.

    Should I put them in my leaf bin or would this be a Bad Thing?

    Thanks

    ReplyDelete
    Replies
    1. I think the way to look at it is that in no way will it make your existing infection worse - even if the spores resist composting they are air born spread and are unlikely to re enter the atmosphere.
      Also the tar spot fungus is quite specific to sycamore and cannot harm anything else

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  2. Our hellebores are covered in magnolia leaves every ate==utumn and I just leave them be. Over the years I wonder what weight of leaves have fallen on that bed.

    ReplyDelete
    Replies
    1. And I am sure they look good as they push through. I have been cutting back my Helleborus orientalis this morning

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  3. Looking forward to seeing the Snowdrops again ! :) x

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  4. Hey!!!! Just to think that my friend Daisy Debs is also commenting! I have a heavy drop of evergreen oak leaves during the Summer. I brush them off plants but leave them as a heavy mulch in between. The soil is heavy clay and on top have gone a couple of good applications of mulch. I wouldn't want to waste any space with leaf bins. Under the leaves it felt much less dry during the summer.

    ReplyDelete
    Replies
    1. And no unsightly cracking of the clay!
      As Daisy is your friend I had better click her and find out more

      Delete
  5. I let most leaves lie on the beds where they fall. In some places they get too thick, and I will rake them, along with leaves on the lawn. The raked leaves are left on compost piles or in out-of-the-way corners of the garden.

    ReplyDelete
  6. They do help hide the weeds hee hee.

    ReplyDelete
  7. Autumn is a wonderful time of the year. It's the most loved season for a whole lot of people. This poem written in alternate sestet stanzas brings out the radiance of autumn and the love of the season by many.

    ReplyDelete

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