Dig vs. No-Dig: Unearthing the Truth About Allotment Yields in the UK
For Generations, The Rhythmic Turn Of The Spade Has Been Synonymous With Preparing The Soil For Planting In British Allotments. Yet, A Growing Movement, Championed By Proponents Like Charles Dowding, Advocates For A “No-Dig” Approach, Promising Healthier Soil And, Perhaps Surprisingly, Even Better Allotment Yields.
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But how do these two methods truly stack up in the varied conditions of a UK allotment? What an Allotment Yields Can We Expect From Each? I started as a traditional grower, and believed in digging. But then changed to No Dig.
Gardening in the soil, as practiced in cottage gardens, allotments, market gardens and small holdings for years
Why?
See the video link above. It explains a lot of what I came to recognise about both methods.
But is there clear evidence about the best method?
Extensive research and trials reveal a nuanced picture, where success often hinges on crop type, soil conditions, the maturity of the system and attitude.
In both cases we need to compare like with like. I see so many traditional gardeners say No Dig doesn’t work after someone has tried it on the plot next door and did it badly. We need to compare the two, side by side, both being done well. But I said the results were nuanced, so read on to understand why.
The Yield Verdict: A Comparative Analysis
Overall Productivity:
No-dig systems, where the soil remains undisturbed and is instead topped with layers of organic matter, typically take 1-3 years to establish their full potential. Once settled, however, they match (or often exceed) traditional digging methods, with much less effort.Charles Dowding’s long-term trials, for example, demonstrate a consistent 5-15% higher yield from no-dig beds, particularly for thirsty crops like leafy greens, tomatoes, and cucurbits.
Fennel Grown in the No Dig Garden
Conversely, traditional digging, while offering an immediate advantage in compacted or newly acquired plots due to instant soil aeration, often sees its gains diminish over time as the soil structure is repeatedly broken down. Especially if insufficient organic matter is added or if the soil is mistreated in other ways.
Crop-Specific Variations in Allotment Yields:
The picture becomes clearer when examining specific crops:
Root Crops (e.g., potatoes, carrots): In the initial year, traditional digging often yields 10-20% more due to the looser soil facilitating root expansion. However, no-dig plots quickly catch up by year 2-3 as their soil structure improves naturally. Trials for no-dig potatoes have shown comparable harvests to dug methods when a substantial compost mulch (10cm or more) is applied.
Legumes and Brassicas: These crops often thrive in no-dig environments, with studies indicating higher yields (e.g., up to 15% more for beans). This is largely attributed to the superior moisture retention and vibrant microbial activity fostered in undisturbed soil.
Long-Term Trends in Allotment Yields:
The real strength of the no-dig method lies in its long-term benefits. No-dig beds consistently exhibit rising fertility over 5+ years, with reported increases in soil carbon by up to 20%. This significantly enhances water retention and nutrient availability, making no-dig plots notably more resilient during drought years.
In contrast, traditional systems can face fertility crashes after 4-7 years if organic matter isn’t consistently and adequately replenished, a phenomenon observed in historical trials.
Factors Beyond the Fork: Influencing Allotment Yields
Beyond the direct act of digging, several factors contribute to the differing outcomes:
Factor
Traditional Digging
No-Dig
Yield Impact
Soil Health
Disrupts fungal networks; increases erosion risk
Preserves mycorrhizae; builds stable aggregates
No-dig: +8-12% long-term organic matter
Weed Management
Buries weeds but brings seeds to surface
Mulch and not digging suppresses 80-90% of weeds. But No Dig still gets some weeds.
No-dig saves 30-50% labour time
Nutrient Availability
FYM dug in releases nutrients slowly
Compost mulch provides steady nutrients
No-dig: +20% nitrogen efficiency
Climate Resilience
Exposed soil prone to drying/erosion
Mulch buffers temperature; retains moisture
No-dig yields 15-30% higher in droughts. Sometimes I see no dig give good yields in a drought while dig gives nothing!
Exceptions and Recommendations: Tailoring the Approach
While the benefits of no-dig are clear, some specific situations may warrant a modified approach:
Heavy Clay Soils: For initially heavily compacted clay soils, a one-off digging or forking can be beneficial to improve structure before transitioning to a no-dig system. This assumes starting on virgin land from scratch. But of course if the allotment or garden has been managed fro some years it will have been dug anyway!
Persistent Perennial Weeds (e.g., bindweed): While traditional digging offers faster initial control, no-dig with a thick layer of cardboard mulch can achieve similar results in 1-2 years by smothering the weeds. Consistent removal of any regrowth is key. But it must be stressed that success depends on constantly removing any above grown weed growth. Leave it a few weeks whilst on holiday and you are back to square one. The other issue is where weeds keep growing in from adjacent plots. Neither dig nor no dig will become weed free if the weed just keeps creeping in from next door!
Resource Constraints: A common concern for no-dig is the need for significant quantities of compost, estimated at 12.5 cubic metres per year for a 250 m² plot. This can be a challenge for home composters. Integrating green manures, such as field beans, can help offset some of this requirement. Personally I add far less and have no issues. I call it modified No Dig. I utilise organic matter such as mown grass as a mulch and haver neighbours deliver it rather than pay the council for a green bin! It saves them money and gives me organic matter. Most allotments have lots of grass paths that can supply a lot of “green gold”. And don’t forget, traditional plots also need lots of organic matter to succeed. Those that fail often do so due to not adding enough organic matter.
Conclusion: A Sustainable Path to Abundant Allotments
In conclusion, for UK allotment holders, no-dig gardening generally matches traditional yields within 1-3 years and can easily surpass them in the long term, particularly when facing increasingly common climate stresses like droughts. The success of a no-dig system hinges on three key principles:
Annual compost mulch: A consistent 5 cm depth of organic compost applied annually is crucial for feeding the soil and suppressing weeds. Or use less but top it up during the season, as I do with mown grass.
Minimal soil disturbance: Tools like dibbers should be favoured over trowels to avoid breaking up the delicate soil structure. No Dig is perhaps badly named. Some digging is sometimes needed to do things such as lift carrots/parsnips or plant a tree.
Soil-specific adaptation: While generally beneficial, clay soils might benefit from an initial or occasional deeper aeration before fully committing to no-dig. I say “might” but am yet to be convinced that the received wisdom on this is correct. I believe that No Dig needs to be modified to work on clay and can be successful from day one. The “might” depends more on the attitude and skill of the grower than on the soil.
For new growers, starting with no-dig can optimise early yields while simultaneously building a foundation of healthy, sustainable soil for future seasons. The evidence strongly suggests that for many UK allotment holders, embracing the no-dig revolution offers a less laborious, more environmentally friendly, and ultimately more productive path to homegrown abundance. But I’m not here to convince anyone. You decide.
Do your own research. Try a small area and learn the way to do it for a few years. THEN decide for yourself.
What Is a Good Yield Anyway?
In the above article I have talked about allotment and garden yields but what is a good yield. I intend to address this in another article and the answer might surprise you. Small garden plots and allotments can produce a lot of food, but most fail to reach their potential. And that applies to both dig and no dig! Watch this space for a future article.
Supporting UK Research for Dig vs. No-Dig
1. Yield Comparisons
Charles Dowding’s Trials (Somerset, UK)
Findings:
No-dig beds produced 5–15% higher yields for leafy greens and tomatoes after 3+ years (Dowding, 2020).
Root crops (e.g., potatoes) initially yielded 10–20% less in no-dig but matched dug plots by Year 2–3 with 10cm+ compost mulch.
Source: Dowding, C. (2020). No Dig Organic Home & Garden. Permanent Publications.
Royal Horticultural Society (RHS) Study (2019–2022)
Findings:
No-dig plots had comparable or higher yields for brassicas (e.g., kale) and legumes (e.g., beans) due to better moisture retention.
Dug soils showed higher initial yields for carrots but required more weeding.
I’ve tried both. No dig requires a lot of work initially and compost can be expensive if can’t make enough of your own. Charles Dowding who I respect has two or three full time workers. I have clayey silt soil and on my no dig beds after a couple of years I find it is difficult to sink a fork in fully cause of hardening lower down So using both methods I have not seen notable differences except for perhaps fewer weeds on no dig. I still like a good old dig for my potatoes.
As for Charles Dowding, he is running a commercial operation and has much more space than most allotments! And his staffing isn’t just around growing, it is about his visits, open days, events and videos as well.
I’ve tried both.
No dig requires a lot of work initially and compost can be expensive if can’t make enough of your own.
Charles Dowding who I respect has two or three full time workers.
I have clayey silt soil and on my no dig beds after a couple of years I find it is difficult to sink a fork in fully cause of hardening lower down
So using both methods I have not seen notable differences except for perhaps fewer weeds on no dig.
I still like a good old dig for my potatoes.
A broadfork might be an idea for loosening soil deeper in the profile and purely by chance I wrote an article eon this topic a few days ago .. see https://www.bitesizedgardening.co.uk/what-is-a-broadfork-why-use-a-broadfork/how-to-dig-for-victory/
As for Charles Dowding, he is running a commercial operation and has much more space than most allotments! And his staffing isn’t just around growing, it is about his visits, open days, events and videos as well.