Or not to dig.
That is the question.
When gardening gurus such as Jim McColl (Presenter of the wonderful Beechgrove Garden TV series) wax lyrical about the new No Dig system of gardening and proclaim themselves converts then the time has come to take a close, in depth look at the whole concept.
The benefits of No Dig can be summarised as:
- An increase in soil fertility, as the soil is rich in compost and organic matter
- Reduced irrigation as the soil is rich in compost and organic matter
- Improved drainage as work tunnels and other natural channels are retained
- Reduced weed growth as the soil is not cultivated which encourages weeds to germinate
No Dig is the result of many years of work by Charles Dowding.
The concept of No Dig is a simple one, if one considers the soil as an organism which nurturing, then digging would appear to be contrary to this concept, as it is invasive and has a detrimental affect on soil life.
From the simplistic view that digging mixes the more fertile upper payers of the soil, which are close to roots with those lower down the soil, to the more complex models that suggest that digging releases, or aids in the release of carbon held in the soil, and so can be detrimental to the environment and may be contributing the the build up of greenhouse gases and so climate change.
The key concepts in No Dig No Weed can be condensed into five golden rules:
- Don’t dig – Use a light excluding mulch to clear perennial weed rather than digging
- Don’t dig – Apply a layer of compost to the top of the soil
- Don’t dig – Even if lifting root crops, just loosen the soil and pull
- Use copper tools
- Treat the soil as a living organism and encourage microbial life
Rule number 5 mentions copper tools.
This has been hotly contested for many years, with many advocates explaining that there is a benefit to the garden from the copper, perhaps a low level residual amount of copper being left in the soil, or a negative impact from the steel used in garden tools. At Enthusiast Towers we have followed this debate for many years and use Sneeboer Tools, which are hand forged Stainless Steel tools, but are considering a trial of copper tools versus stainless steel on our new trial grounds.
Raised beds make so much sense when cultivating vegetables.
- They divide ups the plot, and make management of the plot easier
- They are motivating, in that they divide the plot into easier to manage chunks of land
- They reduce the chance of footfall on the growing area, which enhances soil structure
- They lend themselves to the No Dig system,
Dowding recommends using edging boards to create the raised beds but to then remove them to allow the bed to take on a more natural mound shape and to reduce the incidence of slug and snail attack, as they tend to accumulate on the wood edging. It is worth adding that there is also the risk of preservatives in the timber leaching into the soil and so into crops, or, there is the expense in time and timber of constantly replacing the edgings.
There is no requirement to dig over the soil prior to creating the bed, indeed work that Dowding has done suggested that even an initial dig over (which is so tempting to do) can reduce yield in year 1. Simply apply a thick layer of well rotted garden compost or animal manure. This can be used to fill the raised bed to say a height of 15cm. Every year a further layer of mulch can be added to the bed to replace that lost by humification or mineralisation. A layer of some 5 – 10cm per year should be ample.
We first encountered this system in a Lancashire over 30 years ago on a tomato nursery.
Every year a mulch of some 25cm was laid int he glasshouse prior to the planting of tomatoes. The results spoke for themselves with heavy crops from sturdy plants. From that moment onwards No Dig has been a standard to aspire to.
Dowding does advocate some very limited digging, but only where the roots of perennials are woods, such as brambles.
As long as there is no pan in the soil which would affect drainage then it is simply a case of adding compost to the surface of the soil.
The question of using carpet is often brought up when speaking to allotment societies as the practice is quite rightly banned on many sites as the carpet looks unsightly, gets bound with weeds to the soil and is hard to remove. The same effect can be achieved by thick brown cardboard, unwaxed and unprinted being best. This can be laid over areas of perennial weed to form a light excluding layer and discourage young shoots, it is then covered with mulch to hide it and hold it in place.
Advocates of green manures often continue to dig the manures in, even when following the No Dig system, this is to be avoided, the growing of such crops is fine, they can help to maintain soil structure over the winter by sheltering the soil from heavy rain, however the green manure should be cut and composted rather than dug in. Dowding recommends Synapses alba a mustard which is an annual and is both killed and broken down by frost as a No Dig compatable green manure.
The old adage that soil that has a hoe pushed though it when free of weed stays free of weed is as true to No Dig as to conventional gardening, and a trowel can be used to remove any stubborn perennial weed that dares to show itself.
Hit the Myth – Six myths that are simply not true
- You have ti dig over the soil first, then you can go No Dig – No digging the soil first can reduce yield
- You can use a hoe, and keep the weeds under control.
- Root crops will fork as they grow through the compost, no, they don’t!
- The compost spreads weed seeds, it may, but they can be hoed off easily and digging brings weed seeds to the surface
- You can compost perennial weed, of course you can, if you have an active well managed compost heap
- You cant grow crops like potatoes, of course you can you surface plant the potatoes and then apply a deep mulch to earth them up.
No Dig requires large amounts of compost which can either be bought in or better still made from garden waste and animal manures.
The six golden rules of composting are:
- Creat a heap at least 1m X 1m in size with slatted wooden sides to allow air to enter the heap
- Blend 50% green with 50% brown material to get the Carbon:Nitrogen balance right.
- Water the compost heap to keep it moist, a handful of compost when squeezed should should have enough moisture to see beads of water between the fingers but be dry enough not to drip
- Shredders are good for wood, but green waste does not require shredding
- Compost heaps should have a roof or at the minimum a payer of carpet over the top of them
- Turn the compost once every couple of months.
We have recently purchased all of Dowding’s Books and over the coming months will be sat by the log burner taking notes and reviewing them.
You can follow Charles Dowding on Instagram
Happy (No Dig) Gardening!