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December 7, 2022
Dig / No Dig Trial 2019-2022

Dig / No Dig Trial 2019-2022

Above you see first plantings 6th June 2022, dig bed on left

This trial began in 2007 and ran until 2012 at Lower Farm. It’s to compare growth of the same vegetables in a dig bed and a no dig bed, with all harvests recorded. At both Lower Farm and Homeacres, the area trialled was/is the same – 7.5 sqm/80 sqft for each of the dig and no dig beds.

See this page for 2013-2018 cropping and results.

The graph below shows yields from the two Homeacres beds in the ten years 2013-2022. with totals shown underneath.

2022 harvests were dig bed 91.17kg, no dig bed 113.62kg


A productive year, as long as we watered during the very dry summer. The final three months September to November were the best of the year for new growth, thanks to regular rain and higher than average temperatures. That boosted all the second plantings.

The overwintered broad beans, which you can see in a photo below, gave some nice bean top harvests on 10th March, with 18% more on the no dig bed. Then we planted on 16th March.

Drone view 29th January, dig bed on left
15th March lines ready to plant with no dig closest to camera
15th March beds planted, see 6th June photo for how they grew

Spring was warmer than usual with no significant frosts, and after 1st May, there was no more frost which meant bigger potatoes. Two noticeable relative failures on the dig bed were onions and peas. Last year, the onions grew fine on the dig bed, even if better on no dig.

Sometimes these abnormalities are very striking, and always in the dig soil. Another failure later on was celeriac, which declined to grow on the dig bed.

Drone view early June with dig bed on the left
Harvests to 27th June are almost all bigger from no dig

As soon as space appears, I pop in new transplants through the summer. There is no rotation plan, and often I do it by eye, where I see sufficient space for the new planting to develop mature.

One problem with digging, which I do not see mentioned often, is how you need empty soil to do it. In this trial, it means always that we have to clear the kale in early December from both beds, to have the equivalence, and to be able to dig one of them. It frustrates me because the kale is often cropping really well at this point. It certainly was this year.

Early November, as we enter the last month of cropping in 2022, again, the dig bed is on the left
5th December digging underway as I dig successive trenches and place compost at the bottom of each one in turn
5th December beds both have compost 1.5 wheelbarrows, dig bed took 2.5 hours and no dig 0.5

Once again, after digging the one bed we transplanted broad beans. This year, because of the extremely cold weather coming, we covered beds with thermacrop.

5th December beds planted broad beans
14th December in frost, and I’ve pulled back the cover a little so you can see the broad bean plants looking weathered


Dig bed October 2021, shows few macro-aggregates or microbial volume or diversity, x 400 by Eddie Bailey
x 400 microscope analysis of dig left no dig right with aggregation of no dig making better structure, aeration and resistance to erosion, less unbound material, by Kate Solbakk of Norway September 2019
No dig bed October 2021 found a diatom with testate amoeba to its upper left – note humic-fulvic aggregates, x 400 by Eddie Bailey

Photos of preparing beds December 2020, then plantings and cropping 2021

8th December 2020 and I am digging the dig bed, , making successive trenches to drop compost in, depth 6-8in 15-20cm
The compost is home-made and I drop in the same amount as we put on the no dig bed, and you can see the wheelbarrow of soil at the end which I dug out to make the first trench
8th December 2020 and the left-hand bed is dug with its compost incorporated, the right-hand bed has the same amount of compost on top, and the white flags mark Jane Thatcher’s calico decomposition trial

The calico cotton strips decomposed hardly at all in the dug soil, suggesting a lack of biological activity. In the surface of the no dig bed they decomposed rapidly, but this does not tell us a huge amount about the soil below because most of the cotton was in the new compost. Jane did another trial in starting October 2021, results to follow.

16th March new transplants (then fleeced over) from far end are month old spinach, beetroot, lettuce, shallot, onion, peas with radish & turnip interplants, and Vivaldi potatoes with coriander and dill interplants
Drone photo 26th May with dig bed left and no dig bed right, potatoes at bottom are the closest to grass

Above are the first plantings of 2021, whose harvests you can see in the first table below. The next gallery of photographs are second plantings which we put in from mid-June until mid-July, and there were even third plantings of fennel between cucumbers, and Green Frills mustard after the 2nd crop of carrots.

4th July with second plantings most recently at the near end after peas and potatoes, savoy cabbage next to the dahlias which I had sown April and transplanted May
36 days later on 9th August always with the dig bed on the left. Growth in both parts is strong and also remarkably fast at this time of year, look at the difference in 36 days, compared to the second gallery’s photos difference in 44 days

21st October 2021 with the beds slowly emptying as we take final harvests. Savoy cabbage and kale were the last, on 1st December, to clear the beds before digging the left hand one

And then I introduced a difference, new plantings in December, straight after the digging and mulching! Compare the second and third photos below to see how much growth happened during December, the time normally of dormancy but this year was unusually mild with the average temperature almost entirely above freezing, and some days above 10C/50F

2021 3rd December, Charles digs for ninth time, just this one bed every year! Wheelbarrow has the compost I add to the bottom of each trench
On the same afternoon we set into each bed some spare transplants I had of broad beans, peas, coriander and lambs lettuce on the right hand row of each bed, is almost out of sight
The same plantings now 25 days old, on 28th December after an unusually mild month with the average temperature 7C/45 F

Trial beds' harvests (1.5 x 5 m)

There are charts below, and analysis of the data by a statistician.
This link takes you to the 2019 study of each bed’s soil microbiology.
This is the latest infographic, by Soul Farm UK:


We had a warm, dry spring, a fairly warm summer with some rain, a sunny September then wet in early October. A good year for growing. First plantings were on 13th March, then as usual we laid a fleece cover directly on top.

New plantings by 2nd April after two weeks under fleece, similar vegetables to those grown since 2013
Now six weeks after sowing and planting, dig bed is on your left and its potatoes look stronger, but other vegetables are struggling compared to the no dig on right
May 12th-14th saw hard frost even -3C 27F one night, after much warmth so potatoes were large, but fleece helped lessen the damage to potato leaves in particular

First harvests were radish and turnip in April, then spinach and lettuce, and cabbage soon after.

Cabbage on the dig bed o.80kg had less vigorous roots, left, while they were stronger on the no dig bed 1.13kg, right. Cape Horn F1 on 4th June
Early June with dig left, no dig right: after a sunny May when we watered both beds with the hose

Carrots 12th August dig left, no dig right, 66 days after inter sowing between lettuce, Nairobi F1 gave 7,17kg from two rows

Early summer sees frantic replanting, as soon as harvests are finished of the first plantings. Cucumbers followed spinach and cabbage, kale followed carrots. The last potato harvest in late June freed space for leeks, celery and beetroot. Peas continued until 10th July.

Pushing over onion leaves, as in the photo below, serves to ensure thinner necks and better storage of bulbs. They are multisown Sturon and gave 11kg/24lb onions from 14 multisown blocks, sown 7th February and germinated on the windowsill.

Harvests of the first plantings were 46.4kg/93lb from the dig bed, and 52.4kg/105lb from the no dig bed. This shows how you need less compost with no dig, for a similar result. In this case both beds had the same amount of compost, for 12% more harvest without digging.

By 12th July there are new plantings for succession. Only peas and onions remain from the plantings of March, and I have pushed the onion leaves down to help ripening
July 25th side view shows the wonderful onion harvest and second plantings now well established

As in most years previously, growth in late summer and autumn tended to be more equal. Or look more equal, except for the kale. Harvests continue to be higher from the no dig bed. Harvests of second plantings to end August were 13kg dig, and 16kg no dig.

Overhead view 16th August with dig bed top and no dig bottom. On right are French marigolds and red link, flax
View across on 28th September with no dig in front. From left are rocket & mustards, fennel, radish, dill, endive, kohlrabi, kale, celery, beetroot, leeks, chicory and celeriac. Fowers on left are zinnia, marigold and Dwarf Fantasy sunflower
Just before removing the sides, early December, dig bed on left
One day later, with compost added to both beds and wood mulch for paths



For the seventh time, I dug the dig bed in December and incorporated two large barrows of compost, then simply spread the same on top of no dig.

The compost was 50% horse manure (6-10 months old, from the hotbed of last spring), 25% homemade and 25% mushroom compost/

December digging, compost in the trenches about 20cm/8in deep
A light raking of both beds in January to level the surface, break lumps, disturb germinating weeds
Mid march and the beds are planted, similar veg to 2018, moved along

On 1st April we pulled back the fleece to hoe the dig bed (many tiny weeds) and check progress. All plants sown and planted at the same time.

As last spring (see below), there are problems with the brassicas, beetroot and spinach of dig. Since spring 2018, the dig bed’s growth is weaker than it had been in earlier years, after I first dug the soil from pasture in December 2012.  Yields 2013-17 were just a few % lower but last year was 24% lower, see below.
In the other trial we fork beds and apply compost on top. That reduces yields by less than this method.

Sown mid February planted mid March, dig radish and turnips multisown
Sown mid February planted mid March, no dig radish and turnips multisown

By 12th June there is strong growth on both beds, except for dig’s spinach and beetroot. Most harvests are slightly higher on no dig, except for potatoes. Carrots are struggling on both beds and I am unsure why.

Side view with no dig bed in front, on 12th June
First harvest, one plant of Casablanca each bed on 12th June gave 1.32kg dig, 1.17kg no dig on right

Through late summer and autumn, new plantings on the dig bed are stronger than in the spring. Notably the kale. However most harvests continue to be slightly heavier from the no dig bed.

September 8th, drone view with dig left and no dig right
October 6th 2019 with no dig bed closest

In early December 2019 I cleared the final harvests, the set to and dug the dig bed again, for the eighth time. I spread 1.7 wheelbarrows of nine month old homemade compost on both beds (in trenches of dig), and a little rockdust on each.

Harvest table for 2019.

dec19 new celeriac & kale dig no dig exp 2.65kg .69kg, 3.27kg .43kg P
Digging and compost in trench, took 1h 40min to dig only
Finished result 3rd December 2019 after raking the dig bed on left, same amount of compost each bed

Data analysis by Thibaut Olivier

Given the interest in the statistical analysis of the data generated from your dig/no dig trials, I used my scientific background to carried out some analyses and tried to extract as much conclusions as possible from the data you kindly provide us on your website.

For these analyses, I considered that: no soil bias and no plant outliers were present in the datasets. I also considered that for each year the same varieties were used and that the same surface was allocated for each vegetable type.

Indeed, in terms of methodology, as one of your Youtube followers already suggested, the fact that you apparently replicate your bed preparation types at the same place each year (no rotation) can indeed induce biases due to soil heterogeneity. Also, since the areas and numbers of plant individuals used are rather small in each statistical object, the data may be influence by outliers (data that differs significantly and abnormally from other observations in the same statistical object). We can indeed imagine that one of the plants in one statistical object does not thrive well (because of localised pest/disease or germination problem) and thus leads to an underestimation. Ideally, with such small plots, vegetable weights should be taken one plant at a time to allow detecting outliers and count the number of plants. It is of course a lot of work and not always possible. Another issue is the fact that not all year modality levels (2014, 2015, 2016…) refer to the same vegetable types and probably not to the same production surface for each type of vegetable (although I guess that most of the time it is the case). It is thus difficult to understand if the weights measured (in kg) can be considered as yield (kg/m²) and compared from one year to another for a given vegetable type. Also, variety names are not always mentioned in the datasets so it is sometimes difficult to figure out if the comparisons are possible (“carrot” vs “Carrot Nantes”; “Kale” vs “Kale Cavolo Nero” …).

On the other hand, I only analysed the “No Dig Trial 2013-2019” and the “three strip trial 2014-2019” datasets since I had the impression that, in the “lower farm” dataset, not all data were available on your website.

The datasets were analysed using linear models and the software “R” dedicated to statistical analyses.


In overall terms, no significant differences were found between “dig” and “no dig” levels in both analysed trials considering all vegetable types and all years (P>0.05).

Concerning the “No Dig Trial 2013-2019”:

Comparing “dig” and “no dig” levels, one vegetable type at a time, a significant difference was found for spinach (P=0.0338) and highly significant differences were found for kale (P=0.00726) and kaibroc (P=0.00123). In all these three latter significant differences, the “no dig” level showed greater weights.

Year comparisons showed that weights measured in 2017 was significantly different from those of years 2013 (P=0.0128) and 2018 (P=0.0275). But these results should be interpreted with caution (cf. remarks made here before).

Concerning the “Three Strip Trial 2014-2019”:

No significant differences were found between “dig compost”, “no dig compost” and “no dig manure” modalities (P>0.05) considering the whole dataset.

Comparing “dig – compost” and “no dig – compost” levels, one vegetable type at a time, significant differences were found for squashes (P=0.044) as well as “winter salads, spinach” (P=0.02), highly significant difference was found for parsnips (P=0.00938) and very highly significantly difference for lettuces (P=2.63e-05). In all these four differences, the “no dig” level showed greater weights.

Year comparisons showed that weights of 2014 was very highly significantly lower than those measured in years 2015, 2016, 2017 and 2018 (P<0.001). Weights of 2015 were significantly and very highly significantly different from those of 2018 (P=0.021) and 2017 (P<0.01) respectively. Weights of 2017 were very significantly and very highly significantly greater than those of 2018 (P=0.008) and 2016 (P<0.001) respectively. But these results should be interpreted with caution (cf. remarks made here before).


In overall, no significant differences of weights were found between “dig” and “no dig” levels in both analysed trials. Nevertheless, some vegetable types showed significant to very highly significant weight differences between these two levels. These significant differences were always due to greater weights in the “no dig” level. However, no similar vegetable type was found highlighted in both datasets (kale, parsnips, lettuce and spinach). Kaibrocs and squashes being only present in one trial, the significant difference found in their weights could not be further investigated.