A lovely aspect of no dig is how soils that are usually considered difficult – clay or stony for example – become easy to garden. Soils that are ‘difficult to work’ are usually perfectly fertile, and with no dig we enhance that fertility, while sowing and planting in a soft surface of organic matter. This surface is easier for weeding too.
The no dig methodology in this pack applies to all soils. The only variation I suggest is to use more compost on sandy and chalky soils, whose fertility and moisture retention are poor.
One more consideration is liability to flooding, which is a site and climate issue, and nothing to do with soil management. Raised beds and no dig will help, but you may need to undertake drainage work too.
I can illustrate the flexibility of no dig, using the gardens I have made as examples of working with soils of very different quality.
Stony soil
My first market garden, which I commenced in autumn 1982, was a brash soil full of limestone. I reckon these stones contribute to growth as they slowly turn to soil over millennia. They can hold some moisture too. Growth was strong and healthy, but my parsnips and carrots were rarely straight!
Incidentally, this soil had a pH in the upper 7s, even 8.5 in places. Crops were all good except for asparagus, which I should be curious to try there again using extra compost – I was using less compost in the 1980s. The other difficulty was scab on potatoes, a result of the high pH, and again this would have been reduced by using more compost.
This garden was 10 km (6 mi) from Homeacres, with a similar climate.
During the 1980s I was no dig, but without mentioning it, because an even more standout approach at that time was being organic, still considered to be almost revolutionary – I was registered organic with the Soil Association. My approach wasn’t no dig from the beginning because I used a tractor and rotavator to ‘break the pasture’ when starting a new piece of ground. I used strings to mark out 1.5 m (5 ft) beds and 60 cm (24 in) paths and shovelled soil from paths to beds, which thus became raised.
- Now I do not raise beds like this because I have worked out that there is a bit of mythology about ‘raised beds’, and growth is as good – if not better – on beds that are only a little higher than paths. The only time a high bed could be worthwhile is in areas that are prone to flooding. (Raised beds also put less strain on your back, though in gardening there is always some bending required.)
Another change is that I now make paths narrower, at 40 cm (16 in) wide, but in those days I had access to a lot of free straw and was not short of space. However, in mild winters the paths did need hand weeding, of grass growing from seeds in the straw after the annual mulch of straw had decomposed.
We spread the path straw in spring, rather than winter, to reduce the time it was down before sowing and planting, and in order to keep slug numbers reasonable. Nonetheless I suffered more slug damage than I do now, and also the straw kept soil temperature lower in the paths – not an advantage in spring. This is a reason not to mulch with straw in cool climates, because its light colour means that sunlight is partly reflected and the soil below is slow to warm.
I mulched paths with straw because my main worry when beginning was that weeds would grow more than my crops. I was cropping an area of 6000 m2 (1.5 acres) on my own. During 1982 I had done some homework on the methods and results of other organic growers. Most of them were struggling to keep on top of weeds.
In 1983 my crops were good, and initially this was thanks to the soil being fertile and healthy after several years in pasture and from being grazed by cows. I maintained fertility with 1–2 cm (0.4–0.8 in) of compost each autumn or winter (less than I use now), but I was double cropping much less as well, and yields were lower than at Homeacres.
Another result of the thin amount of compost mulch was more germination of weed seeds on all the beds. We did a fair amount of hoeing and were often hitting stones, making it hard work.
White clay in south west France
Tanger, my no dig garden in France from 1992 to 1997, was on the densest white clay (called Boulbène) that I could imagine. It was not liked by neighbouring farmers who had the same soil.
Back in 1992, I did not appreciate that Boulbène soil was so dense in winter that it was prone to being waterlogged; then in summer it dried very hard. Yet growth was excellent in the garden when I left it undisturbed and spread compost mulch. In the farm fields I knew only to plough, and struggled!
My vegetables were admired at market, including by farmers who knew the soil I was growing in. I grew organically too, and at first they were sceptical of a ‘bio’ (organic) approach, especially the no fertiliser part. However, several of them switched to it later when they noticed how many customers wanted that level of quality and would pay more for it.
At first in France I was worried about weed growth and moisture retention, having seen the amount of weeds growing when we viewed the farm in September. I mulched with hay for a couple of years, before noticing a fair number of slugs and weeds growing from seeds in the hay. Again I switched to compost, making it easier to control weeds and retain moisture at the same time.
Yellow clay in Somerset with a loamy surface
After France I made a market garden at Lower Farm in Shepton Montague, Somerset, the village where I grew up and had my first market garden. It was one mile away and at the other end of the village, but on completely different soil!
In November 1999 I took over a third of an acre of wet soil, which had been compacted in wet weather by heavy machines – it was the bottom triangle of a steep corner, awkward for large tractors. In some places I would find putrefying lumps of grey and airless soil, whose surface was sticky in winter and hard in summer.
It was a challenge, and growth in year one was barely even average. This was partly because I had spread no more than a 3–4 cm (1.5 in) cover of old horse manure on the beds, after clearing the weeds by pulling them – a sticky job. If I had known then what I know now I would have started with a thicker mulch, and in some places would have used cardboard.
Gradually my compost mulches changed the soil and gave it structure as it returned to life. Soil organisms multiplied and restored air, improving drainage and plant growth without any cultivations or forking. During the second year there was good growth; for example parsnips grew deep and long into the dense soil, which was also being aerated in dry summer conditions by some cracking.
I could have had faster results and fewer weeds by applying, say, 10 cm (4 in) of old manure or bought compost. However, at the time I did not need high yields – sales were slow, before I discovered salad bags – and I was doing some building work.
Gradually I was learning, by observation, how soil can improve without physical intervention. In the first two years I spent a lot of time hoeing the hard surface until it became softer on top, thanks to mulching.
The photos above (bottom right) shows an unintended effect of cultivations in general, in this case of ploughing the field above my vegetable beds. The first photo is from October, after 10 mm (0.4 in) of rain had fallen in 30 minutes, and water is running out of the cultivated area, down along my paths. In November 2011 it was similar after heavy rain.
Every autumn at Lower Farm I spread 3 cm (1.2 in) of compost. I used different types: my own, old horse manure, green waste compost, or cow manure which I had bought. From year three onwards my vegetables were abundant. Furthermore weeds were few, and easy to pull or hoe in a surface which stayed soft in dry weather and was not sticky in winter.
My conclusion is that when you feed earthworms and other soil organisms from above, it allows soil to recover damaged structure over time.
A rare exception is with soils where a true pan has developed, such that growth and drainage are awful. In this case a dig or forking is worthwhile, but only once. Incidentally, what is sometimes referred to as ‘compaction’ is just soil’s natural firmness, which is good.
Homeacres soil
The first thing I did when arriving at Homeacres was to dig a hole. The estate agent was bemused because she’s not used to people ignoring the house!
I was delighted to find the dark silty soil you see in the photographs. It was only later that I discovered Homeacres had been a nursery, and that was another sign of good soil.
One thing I notice about the soil here is that it becomes very sticky after any kind of disturbance. For example, after planting a tree in the winter, which necessitates digging a hole, this surface is extremely sticky for the first week. This would make it difficult, if we were doing any kind of digging and rotavation.
Clay in Kent
In 2012 I was asked, through Sarah Raven, to advise the National Trust about their uneconomic market garden at Sissinghurst in Kent, South East England. The soil is yellow clay with not much loam on top, and it had been damaged by two years of machine cultivations, on about four acres of land. Harvests were small and weeds were plentiful. The land was certified organic, and they were being advised by the UK’s Soil Association.
I saw immediately that for the amount of harvests they needed the land area was too large. I recommended five things in particular:
- To sell all the machinery, of which there was a lot.
- To concentrate on high value crops, rather than growing field crops such as potatoes.
- To grow everything in the 3000 m2 (0.74 acre) area which already had beds. These were being dug and were weedy, with not much compost used.
- To concentrate all the compost for use on the beds in this smaller area and make it no dig. Also to buy some green waste compost.
- To reduce the number of staff (many were volunteers) and to give them better support, such as a greenhouse for propagation.
The Trust implemented these changes and, within two years, the garden was needing much less input of time for a similar value of crops and from an area a quarter of the size.
Sandy soil
A final observation about soil types is from a friend who gardens on sand in Florida. Sand is hungry for food and moisture, but, since switching to no dig with compost mulches, she has found that her harvests are large and continue for longer.
The climate is hot and wet, and drainage is better now with no dig. Rainfall is 1300 mm (51 in) per year, with two thirds falling in the summer months when it is intense.
Why adding compost does not raise the whole garden
I am often asked the question: ‘Won’t I need a stepladder to get into my garden after years of repeatedly adding compost?’
The answer is no, and these are the reasons:
- Compost is of low density and settles to a reduced volume within a few months (though it may look a lot when you first apply it). This is also why I recommend walking on compost when making new beds, except if it is soggy.
- Compost is food for soil organisms, whose excretions are much denser than what they eat – notice the solidity of worm casts.
- The plants you grow and harvest take nutrition and carbon out of the soil.
An initial higher dose of compost is an investment in your growing for several years ahead. After year one, and in every succeeding year, you apply less. About 2.5cm / 1in annually.
Per weight of harvests taken you need less compost for no dig than for dig. The harvests from my two bed trial demonstrate this over 10 years of cropping. We have harvested 12% more food from the no dig bed, using the same amount of compost as dug into the dig bed.
When set against the reduction in time needed to manage a bed or garden over several years, the amount of compost is small.
