I was quite excited about trailing a no-dig garden when I started up this RED Gardens project.
I had been reseaching the possibilities of no-dig methods,
and I saw that it was becoming a major part of gardening lore, so I wanted to try it out for myself.
It just made so much sense to not actively damage the soil ecosystem.
But within the different gardening methodologies that I am trailing as part of this RED Gardens project,
the No-Dig garden has been the most problematic for a number of reasons.
While there are a number of different approaches to minimise or eliminate the tilling soil,
I had been exploring the Permaculture movement and reading all about the possibilities and
benefits of a deep litter mulch. I was especially interested in the descriptions
by Toby Hemenway in book called Gaia’s Garden. He details a deep litter mulch with layers
of soil amendments, newspapers, cardboard, a thick layer of bulk organic material, compost
and a top covering of straw or leaves. I used a simplified version of this to start
this family scale garden a couple of years ago.
It seemed like a relatively easy and useful way to transform the grass pasture into a
productive vegetable garden, even if it did involve a lot of material.
In hindsight, I didn't do a good enough job, partially because I didn’t have the time,
but also because I didn't enough material to provide a deep enough cover.
It probably would have been better to use the material I had to only establish part
of the garden, and then to finished the rest of the garden when more material became available.
I also wasn't patient enough and I probably should have left the garden for a season before planting.
In the end the first covering of cardboard
and mulch didn't get rid of the weeds, especially the scutch or couchgrass which persisted in pockets.
I also ended up adding a bunch of weeds that
I imported with the straw and hay material I used for mulch.
There's also this idea that no-dig is somehow really simple and foolproof, that you can
just mulch and leave it and everything will be fine, and I think this is part of the reason
why I didn’t give enough care in the first place, or wasn’t attentive as I should have
been for the first few seasons. Patience and a little bit more care in the
first season would’ve made the garden more successful in subsequent years,
and probably would have been a lot easier.
While I can blame my own lack of care and attention on some of the problems that I've
experienced, other problems seem to be inherent within the methodology itself.
Firstly, the mulch became a massive breeding ground for slugs, and as a result I've had
many crop failures. I've tried dealing with the with slugs using
beer traps, egg shells, organic slug pellets, picking them out by hand, and many other methods,
but all of them had their limitations. I haven't tried ducks, which is the most widely
suggested solution, because the context of the garden just isn't appropriate for them.
It seemed to be a futile battle in dealing with the slugs, not matter what method I tried,
especially when I was providing them with an ideal breeding ground at the same time.
Another significant flaw of this deep mulch no-dig system, at least within the context
i’m in, is that the soil underneath remains too cool.
A deep mulch is very useful in hot and dry regions, where the benefits of conserving
moisture and keeping the soil cool can be huge, but that is not the case with the maritime
climate here in Ireland We generally have too much moisture, but more
importantly, the soil often isn't warm enough, especial in the spring, where any mulch covering
insulates the soil and delays it warming up. With our cool summers, the plants need a longer
growing season to produce a yield, and so there is a pressure to get the plants in the
ground earlier. But if the soil is cold, then seed germination
can be patchy and the recovery and growth of transplants can be very slow.
Last year, only 25% of the broad or fava bean seeds that I sowed germinated, but the same
seeds planted in the other gardens in the same day had almost 100% germination rate.
There are ways around this, such as scraping back the mulch material to expose the soil
so that it can warm up with the sun, but this would disturb the soil organisms which would
have colonised this mulch layer, and goes against one of the foundation principles of the no dig method.
Of course, I'm not the only gardener to struggle with this, and Charles Dowding has developed
a no-dig methodology that seems much more suitable for temperate climates.
He uses aged manure or compost as a mulch, rather than undecomposed organic matter.
This makes a lot of sense, as it doesn’t disturbing the soil, it adds lots of fertility,
it won’t be a breeding ground for slugs and it'll warm up relatively quickly in spring.
But the main limitation is the sheer volume of material that would be needed.
He recommends using an initial layer more than 5cm deep of well rotted manure or compost
on top of cardboard or paper to establish the garden.
This would equate to more than 5 m3, or 50 wheelbarrow loads to cover the full 100 m2
garden that I’m growing in. Not only is hauling in and spreading all of
that material a lot of work, getting it in the first place can be difficult.
This volume of compost is about twice the amount that I would use in the Intensive Garden,
and more than I would even use in the Polytunnel Garden.
In the past few seasons I've been producing about 7 or 8 m3 of finished compost in a year,
and if I followed this advice most of it would have taken to establish the No-Dig Garden,
leaving not enough for the other gardens. But when I started this garden I had much
less compost to work with, and I think a lot of gardeners are in a similar situation and
I think this is one of the key limitation to using Charles’ method.
It’s been quite difficult to get supplies from elsewhere as all of the organic farmers
that I know in the area are quite hesitant to get rid of their manure.
While there are a few non organic supplies of manure available, there have been issues
with herbicide contamination in the past. So, if you had access to that kind of volume
of material, then starting a no-dig garden in this climate with a thick layer of compost
is probably a great thing to go, but where does that leave the rest of us.
And even if I had that kind of volume of material, I wonder if it would be better to spread it
over a wider area, to make the most of that valuable resource, as cm 5cm seems excessive.
But then the question remains how do you start a no-garden in this context when there are
significant problems with a deep layer of compost or a deep layer of straw?
And I don’t really have an answer to that question yet.
Because this garden is already established, I don’t have the same need for a deep weed
suppressing mulch, so I've been shifting more to a sustaining no-dig strategy, or rather
several strategies. I'm trying out a number of different approaches
and working them into the crop rotation that I have established, and trying to match each
method with the needs of the crops that will be growing.
I use Charles method of mulching with lots of finished compost before the hungry brassica
crops. I then use partially decomposed rough compost
for the potato and squash crops, with low fertility mulch being added over the growing
season. The remaining mulch is scraped back prior
to the beans and peas to allow the soil to warm up and these crops are then mulched with
grass clippings in the warmth of the summer. I’m still not sure how best to treat the
soil after the beans and before the carrot and onion family crops, and I suspect that
covering the bed with a ground cover may be an appropriate option.
But this season I was able to get a load of raw apple pulp from a local apple juice producer,
and decided to spread it as a thick mulch on the soil, just to see what would happen.
I really won’t know what the pros and cons of this slightly radical approach could be
until I try it.
Regardless of the method that I am trying, three key aspects remain the same.
I avoiding digging as much as possible, but I’m trying not to being too precious about it.
All fertility is added in the form of organic
matter to the surface of the soil, so that the biology can do the work of building the
soil structure underneath. And to make use of the bulk resources that
are abundantly available locally, while figuring out how avoiding potential problems of slugs,
contamination and possible fertility imbalances. And in this process there’s lots to learn
and explore, and no doubt things will change and evolve as I work to skill up and hopefully
figure out what works best in this context.