Monday 1 October 2018

Don’t fluff up your soil

Use it and lose it; show off your crumbly soil and its gone!

Blogger Sue Garrett took great delight in picturing me with a spade (Damn it I was digging up an alstroemeria for her)
My older readers have heard all this before but I feel today I need to reclaim my no digging credentials. In particular I want to challenge the crazy outmoded idea that regular stirring the soil around  established plants somehow aerates it.

It’s the wrong type of aeration. Instead of a network of channels made by natural causes such as roots, worms and natural cracking that facilitate air movement and drainage instead there is imposed a complete destruction of soil structure. Oxygen reaches the most intimate organic structures and oxidises them away. Soil particles are torn apart and exposed in tooth and claw.
Worse when settling out after this damaging process, wetting and drying impose rocklike hardness and it becomes necessary to cultivate again. The trouble with intensive soil cultivation is that although it provides excellent short term conditions for sowing and establishing new plants the effect fades away and a gardener or farmer needs to cultivate again. In particular fluffing of the surface soil turns  gardeners into soil stirring junkies.

Mangling roots and soil amongst growing plants is particularly stupid when extensive surface roots are just chopped away. Deeper digging is even worse and for example autumn disturbance in the herbaceous border kills the roots which sustain life over Winter when drainage is poor. Such cultivation is bad for both plant and the soil

Crumbs and soil particles
Intimate mixtures of particles, organic matter and living organisms are made in a worm's gut
A mystery to new gardeners, particles and crumbs are completely different. Particles are those indivisible particles of sand, silt and clay. You can see them as they settle or float when you stir a handful of soil in a beaker of water. They only change their nature over multiple thousands or millions of years. Don’t be taken in by those shysters who claim particles like ‘rock dust’ will improve you garden.(although of course large additions of silt, sand and clay can make for physical change, sometimes a bad one)

Millions of tiny clay particles all squashed together. Even here look at the benefits of worm action
Crumbs are aggregations of particles and organic matter. They are particles mixed together loosely combined by natural gums and glues and other beneficial organic manifestations. In the last couple of decades the significance of fungi in this binding together has been discovered. Strands of mycorrhizal fungi and their (relatively slow) breakdown product glomalin has transformed our understanding of soil structure.
Water stable crumbs are the gardeners dream. Clay rich soils come closest to making them

Worm casts at the  surface on stony undug soil in Worsbrough cemetery
Worm casts are not essential to form water stable crumbs but are often part of the process
Frost mould - just give it a kick
It is sometimes appropriate to make a seedbed. Traditional horticulture exploits Winter frost to breakdown lumps and clods A thwack with the back of the spade or a kick of the foot works wonders
Farmers these days sow all year round and have wonderful machinery to prepare the ground for them. Well actually brute force.
So too the gardener, although I do believe many gardeners prepare their planting tilth excessively fine and too often.
Tilth making is a delicate process and where followed by heavy rain or irrigation can damage the soil in the same way as soil is damaged  in the afore mentioned beaker!
Unfortunately tilths on certain sandy soils slake down in heavy rain and if followed by rapid drying form a hard cap.
The good news is that most UK soils are very resilient and occasional seedbed formation does little long term harm

Tilth and the no dig gardener
The settled soil in a no dig garden is firm and cohesive. It’s softer where the gardener uses extensive mulching of compost but this is not my way. Don’t confuse a settled soil with compaction and if the surface is disturbed by a light forking its lovely crumbly structure is revealed. Don’t do this to tell the world you will have a beautiful soil - exposing it induces its destruction. Don’t confuse soil with your childhood buckets of loose sand on the beach! Good soil should be a cohesive whole, not lots of loose granules.

After two years of no dig the surface heavy clay soil in Lyndi's field is starting to crumble
Although benefits of stopping to dig can arise after six months or so the real benefits arise over the years. The longer soil is left undisturbed the better. In due course the surface starts to reflect beneficial natural processes not least the action of worms casting their intimate mixtures of soil and organic matter. Should the gardener wish to make a seedbed all he needs to do is to lightly scratch the surface with a rake or for larger seeds make a drill with a stick or a hoe.
Not that the no dig vegetable gardener needs to make seed beds too often. For most vegetables it is best to raise plants and pop them in. (Do it yourself of course, garden centre plants might cost more than the value of the produce)

The seed of these annuals was just scattered and lightly raked in
No dig ornamental gardens only rarely need seed beds. Let plants seed themselves or just scatter them around

Can the no dig gardener hoe to control weeds?
Yes, but not deeply in the traditional way loosening all the soil surface. Just hoe the weeds severing them at or just below ground level and leave them to desiccate and die.
I generally control weeds with glyphosate but sometimes hoe in dry or windy weather.

I would find it very uncomfortable to use the hoe on the right
Unfortunately most dutch hoes these days are manufactured with turned up blades. Madness and totally useless. I cannot believe any owner of such a hoe, hoes at all! You need to find a traditional hoe

My own sandy soil grows luxuriant liverwort in wet weather. I treasure it around my pond and generally tolerate it in my borders. My friend Peter has a consuming hatred of it and in dry weather lightly hoes or rakes it away!

Dust mulch theory
This old idea that loose soil around plants conserves water is complete nonsense and was first discredited by research sixty years ago. If you want to know more about this read my article here

It is sometimes necessary to disturb the soil Keep it to a minimum. Let the quality of your plants tell the world what a good soil you have and what a good gardener you are.

I wrote about hoeing here
Thank you Sue Garrett for the opening picture. Sue visited my garden recently and made an excellent video of my acre garden. You won't find very much loose soil.

Despite my above comments I prefer not to look at too much of an open soil surface. Use my search box to find mulching and ground cover

I am starting to use Chewing fescue grass as ground cover in wilder parts of my garden


  1. Hello! Is there a way of me turning off the background of your blog? For some reason my eyes don't get on with it and there are bits I can't read (and I would love to read all of it!)

    1. Hi Nicky
      You need to access in reader mode. When I go into the blog by safari it offers me the choice if I press the icon of little vertical lines to the left of the title bar above the blog.
      When I use Chrome the icon is not there - I think entering reader mode is availabe for most devices and browsers - but you might have to check it out. I am seeing Cathi tonight who knows about these things....

    2. Ah, thank you - I will have a play. I do everything on my phone but might get out the laptop!

  2. There you were spade in hand, head hung in shame! Thanks for ther link.

  3. I was contemplating this very topic... as I dug up my potatoes yesterday!


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