No Dig Vegetable Growing
An introduction to No Dig Gardening
Imagine a flourishing vegetable garden achieved without digging! Does it sound too good to be true? Charles Dowding has been using the ‘No Dig’ method with great success for 14 years. Here, he answers some commonly asked questions.
What does ‘No Dig’ mean?
No Dig means minimal soil disturbance and feeding soil life. Occasional hoeing, digging a hole to plant trees, and using a spade to remove parsnips are sometimes necessary – so it isn’t all plain sailing.
Spreading a thin mulch of compost every year, on all beds, provides food for worms and other soil life to maintain air channels and a good structure. My experience of thirty years has revealed how plants love to grow in undisturbed soil, whose compost-fed surface becomes dark and crumbly, whatever the original soil type.
How do you get started with No Dig gardening?
Initially some digging of large perennial roots may be required, such as docks, brambles and woody plants. If the soil is full of long lived perennial weeds such as couch grass and bindweed, you can mulch for a year with black plastic, growing nothing except perhaps a few large plants through the plastic, such as courgette and squash.
In the first year only of vegetable growing, spreading two to three inches of homemade or purchased compost or animal manure, to help worms improve soil structure and raise fertility is advisable. I suggest when starting no dig that you begin with one or two beds and experiment to find your favourite methods. It may seem strange at first, planting into a (well broken down) mulch on top of undisturbed soil, but the potential rewards are huge, especially the reduction in weed growth.
How do you prepare soil for sowing?
I suggest you make the beds four foot wide and with no wooden sides. Pathways of about eighteen inches mean that you need compost for about two thirds of your area. The start of the year is in autumn, when a vital part of the annual rhythm of work is to clear last year’s plants and any weeds, then to spread a good inch of garden compost or animal manure. Frosts then break up the lumps and by spring the surface will be soft and dark: - excellent for sowing and planting. You can use a rake before sowing, just to smooth out the surface of beds.
How to create and maintain pathways?
Creating pathways using bare soil is best, as this means less slugs and allows vegetables to root into pathways, which can be weeded and hoed just like the beds. Spreading about an inch of rough compost on paths in the first year only; municipal, green waste compost is good for this. Also there is always a little compost falling from beds onto the paths and that is fine because path soil needs some feed.
Why switch to No Dig?
My experiments (see below) suggest that soil which has been disturbed needs time to heal. Most scientists are only recently discovering about the life and structure of soil, how it is a delicate living organism which responds bountifully to correct care and feeding. Professor Elaine Ingham in the USA has pioneered many new understandings.
In my garden I am growing superbly healthy and high yielding plants with less addition of nutrients than is sometimes recommended – for instance, I do not feed tomatoes in the polytunnel (yet they yield really well). I never use fertilisers, even organic ones, and I think the ever increasing amounts of soil life are mobilising my soil’s previously undeveloped potential, by maintaining an open structure for roots to travel in, and then helping those roots to find what they need. My salad plants have a glowing lustre to their leaves, much commented on by many customers. If we can work with nature in a way that mimics her principles, she looks after us better.
What is a mulch?
A mulch is a material such as decaying leaves, glass clippings, bark or compost that is spread around a plant to enrich or insulate the soil.
Do you recommend thick mulches?
For growing most vegetables I use just the thin mulch of compost, but mulching also depends on the climate, weeds and on what you are planting. Thicker mulches of partly rotted organic matter are good for dry conditions and for smothering abundant weed growth in the first year of No Dig, also for mulching soft fruit bushes and large vegetable plants such as courgette. Thinner mulches of well decomposed material are good for planting salads and sowing carrots.
Doesn't soil have to be turned every three or four years to increase air?
No! My oldest beds are in their fifteenth year of No Dig and growth is still improving. When soil inhabitants are fed, they can build an enduring structure which is aerated but firm: for instance I can walk on my beds if I need to, and push wheelbarrow loads of compost on the permanent paths of soil. Yet roots such as carrot and parsnip go down happily, and I often pull parsnips with two foot roots.
What about weeds?
Keeping weed free is a quick process, as weeds germinate less in undisturbed soil, and are easy to hoe or pull out of the soft surface. I suggest you acquire the habit of regularly pulling the few weeds that grow so that none ever set seed, resulting in clean soil and less weed seeds in the compost heap. The majority of hoeing happens in early spring, when a small flush of weed seeds germinate from their winter dormancy, most of them from compost and composted manures that have been spread.
Cultivating soil is equivalent to ripping somebody’s clothes off. If that was done to us, we would grab anything we could to re-clothe, and soil is the same: it quickly re-covers (recovers) itself with weeds. I have come to appreciate how a well-run, No Dig garden has calm, happy soil which grows abundant produce and relatively few weeds.
Do you need fertiliser in No Dig gardening?
No Dig allows the soil food web to remain active, and can make nutrients available when needed. The only mineral additions I make are occasional dust from volcanic basalt, and seaweed, because I have a feeling that many soils are low on trace elements and therefore benefit from small additions of these intensely rich soil foods. Adding them to compost heaps or animal litter is another way of increasing soil health.
Is No Dig gardening a new practice?
No Dig has been practiced forever, yet has never caught on generally. I am unsure why, but have noticed that few people like to be seen as ‘different’! However I am now finding a rapidly growing interest in No Dig, and once gardeners have experienced the success and ease of practising it, they are keen to keep going. Some National Trust gardens are adopting the practice, for instance Barrington Court and Knightshayes.
I maintain a website www.charlesdowding.com which is full of advice on many topics, including five years’ results from my experiment of four beds 1.5 x 2.5m, comparing growth of the same vegetables between the two dug beds and the two un-dug beds.
What has the experiment revealed so far?
Total harvests are similar from the dug and un-dug beds, but there are also some fascinating differences. Many vegetables grow faster in spring on the un-dug beds, especially onions and spinach, while there are more weeds on the dug beds. Parsnips root better into the un-dug soil but potatoes are the only vegetable to prefer the looser, dug soil.
Slug damage is more evident on the dug beds, I think because their compost is buried during digging, so that slugs have a smooth surface of clay soil to slither over, compared to the rougher surface of compost on un-dug beds. And when watering, water runs more easily into the un-dug soil!
Find out more about Charles Dowding.