Last year I put up a new polytunnel in the Black Plot in less than Ideal circumstances.
It was already getting late in the season, and I was in a rush to get some of the summer
crops in, and as is often the case I hadn’t done enough prep work.
The site was very rough and uneven, and there was a fair amount of stones and other debris
to be cleared, including some buried plastic from a former polytunnel.
There was also a lot of perennial weeds, especially scutch grass which can be really problematic
to get rid of.
I did have some options.
I could methodically dig out the entire area, and maybe get in a few friends to help.
I could rent a rototiller to do some of the heavy work, but the plastic and other debris
would probably get in the way, and the roots of the weeds would still be there to regrow.
I didn’t have enough mulch material to be able to cover the entire 110 square meter
space, and I’m not sure whether that would be the best option in this context.
I definitely didn’t want to spray with herbicides, and I didn’t want to wait any longer and
lose more of the growing season.
Thinking more holistically, especially about the types of plants that I was planning to
grow for the rest of the season, I realised that the beds didn’t need to be perfectly
clean, not just yet anyways.
I was planning to fill the polytunnel full of fast growing aggressive crops, such as
tomatoes, cucumbers, climbing beans, courgettes or zucchini, and a few squash.
I was also intrigued by the possibility of using a woven ground cover fabric to cover
the entire soil surface within the polytunnel, and to burn holes into it for each of the plants.
I’d seen this method used by a number of different growers and I wanted to try it out.
And this opened up the possibility of it being much easier to prevent the regrowth of any
of the persistent weeds that remained in the soil.
After I put up the polytunnel frame and covered it with plastic, I used the simplest method
I could to turn the soil.
I took a sharp spade and I cut the sod into manageable chunks, and then turned each piece
upside-down into the space left by the previous piece.
This is similar to the ‘lazy bed’ technique that I've used in other parts of the Black
Plot, but even more rudimentary.
This process chopped up some of the larger roots, and broke up the extensive rhizome
root network of the scutch grass, and buried all of the vegetation.
I didn’t worry about removing many of the roots, except to clean the surface and establish
the beds, and I probably did more work that I needed to, as it seems that I prefer a clean
and tidy garden to start with.
I decided to use three long overlapping sheets of ground cover fabric, and to melt holes
down the centre of the five permanent beds that I wanted to establish.
Making the holes was a relatively easy process, using a propane torch and a mask or stencil
made out of a sheet of plywood with holes cut into it.
And the melted plastic helped to form a reinforced edge around each of the holes.
I set all of the holes 40cm or 16 inches apart, which is a pretty good spacing for most of
the types of plants that I wanted to grow, and if a plant needs more space, I could simply
skip a few holes.
And each of the holes was made large enough for me to get my hands down into it for transplanting,
but small enough so that most of the bed was covered.
I set up a drip line watering system on each of the beds, that would go underneath the
ground cover fabric.
This is the first time I’ve used this type of system, but I’m hoping that it’ll save
a lot of time, reduce evaporation, and keep down the level of humidity in the polytunnel.
As expected, this garden was quite easy to manage, and there was good productivity despite
the shorter growing season.
Some of the perennial weeds did regrow, in the holes and in the space between the edge
of the ground cover fabric and the plastic of the polytunnel, and annual weeds sprouted
wherever the soil was bare.
I did find it difficult to remove some of these perennial weeds, because the roots of
the plants were in the way, so I ended up just pulling off any vegetation that appeared
whenever I could.
In hindsight, I could have cut cardboard pieces to act as collars around the base of each
of the plants, to cover the holes and exclude the light, and in the end this probably would
have been less work than the weeding.
But with such strong and vigorous plants, and the overshadowing they would have caused,
I’m not sure how much competition there would have been from these weeds, if any.
There were a few fertility issues, with signs of nutritional deficiencies developing on
some of the plants later in the season.
More compost probably would have helped, but I suspect that part of the issue was the water
stresses that might have developed, which can be an issue with the calcareous soil that I have.
My lack of experience with the drip line watering system meant that it was difficult to judge
how much water was going into the soil, and I didn’t have a water meter to be able to
keep track of the volume, and the ground cover made it more difficult to see how dry the
soil was actually becoming.
After the main summer crops were finished, I decided to not grow anything in this polytunnel
over the winter, to leave the ground cover in place and to give myself more time to establish the beds.
As I dug the soil over the winter, I found that all the vegetation was decomposed, and
most of the weed roots were dead.
Some annual weeds were still growing in the holes of the ground cover fabric, and there
were pockets of scutch grass as well as nettles and other perennial weeds.
It would have needed at least another season to ensure that all of these roots were killed
off if I hadn’t dug them out.
I carefully dug out the five permanent beds and tried to remove all weed roots and any
stones that I found, as I’m probably not going to be digging these beds again in the
near future.
I didn’t bother digging out the paths between the beds, as any weeds that regrew in this
area would be killed off when covered with the ground cover again.
I added lots of compost and fertility to the beds, and relaid the drip line watering system.
I didn’t put down the ground cover fabric just yet, as I wanted to sow multiple rows
of fast growing spring crops first.
I plan to put the ground cover back down just before the main summer crops are transplanted
into the polytunnel later in the spring or early summer, so the ground will only be bare
for a few months before being covered again.
Any of the weed roots that I missed are probably going to regrow, and no doubt there are lots
of annual weeds seeds in the soil that are going to sprout.
It’ll be a little bit of work to make sure there’s not too much competition for the
spring crops, but its not something that I’m going to worry about too much and I won’t
need to clear the beds again before laying down the ground cover fabric.
Overall, I think this has been a pretty good method to go from really rough and weedy ground,
to a clear and productive growing space.
It took about 16 hours in 2017 to do the initial digging and levelling of the garden, then
a couple of hours over the growing season to do some of the weeding, and then almost
10 hours in 2018 to finish clearing the ground and establish the beds.
27-28 hours to establish clean beds by hand in a 110 square meter garden is still a lot
of work, but not bad compared to the 600 kg of high value vegetables that I harvested
in only part of a season.
And now the beds are well established for the future.
It was also useful to split the task over two seasons, to let time, nature and the ground
cover help with the task.
If I was to do it all over again, I could let the ground cover fabric do even more of
the work.
I could have dug out a thin strip down the centre of each of the five beds, reducing
the amount of digging by almost 80%, and then I could have cut back the rest of the vegetation,
levelled the ground a bit, and covered the whole thing with fabric.
If I’d found a way to block out more of the light from around the planting holes and
in the space between the ground cover fabric and the polytunnel plastic, it would have
saved even more time and effort.
And if I hadn’t been so particular about establishing clean beds this spring, I could
have perhaps reduced the total time spent to less than 10 hours, or about 1/3 of what
I actually invested.
But that's just speculation, as I’ve no way of knowing what issues would have developed
if I’d done this, or what impact it would have had on the health or yield of the plants.
No doubt there’s problems with this general approach, and perhaps even some benefits that
I’m not taking advantage of.
It will be interesting to see how things evolve over the next few seasons, as I continue to
use this plastic ground cover under the main summer crops.
Of course there are financial and ecological costs to this type of ground cover, and that
needs to be taken into consideration, but if I'm careful with it, it should last quite a few years.
I’d really rather not be using so much plastic, but if I’m going to use it, I want to get the most out of it.
There are some serious issues with the use of plastics in a garden, but they can be so
beneficial, and this is an issue that I want to tease out in a couple of other videos that
I’m planning to make in the future.
For now, I’m really excited about the start of the new growing season and a lot of the
other videos that I’m planning to make.
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