Many of the plants that I want to grow in the polytunnels in the summer need to be controlled,
or at least have something to climb or to hang from. The main reasons for doing this is to
prevent the plants from taking over the space, and so that I can get in amongst the plants to be able
to care for them, and to be able to harvest from the continual abundance that they can produce.
This often involves me tying them up in some way and pruning them back,
often quite a bit, with the main aim of increasing the yield that I can get
from this high value growing space. I have been doing this with an increasing range
of vegetables each growing season, and this year I tried a few different techniques and
started using some pieces of equipment that are specially made for situations like this.
Many of the heat loving summer fruiting plants that I grow in the polytunnel are essentially hung
from the steel frame, or more usually from the wire or rope strung across the polytunnel hoops,
and this involves a lot of twine or string of some kind. In the past I have bought small rolls
of garden twine for this task, which are quite expensive, and have also reused twine cut from
straw bales, but this was a hassle to work with and generally degraded within a year or two.
I have more recently used builders twine, which was inexpensive and easy to get in my community,
but it was a hassle to separate from the crops at the end of season, to keep it out
of the compost pile. I also wanted to reuse the stuff for several years, to have less waste,
but this created storage issues and often ended up with a tangled mess. So this year I invested in a
big roll of biodegradable twine made specifically for supporting crops for commercial growers.
It is a mix of two different types of twine, one providing strength and the other wound around it,
which seems to be there to provide some friction. And it is apparently fully compostable,
which means that the process of clearing out the remains of the crops at the end of the season will
be a lot easier, as everything can simply be thrown on the compost pile. I have also found
that knots tied in this twine don’t slip, and it seems to be strong enough to do the job, so far.
I am glad I made the switch to this twine specially made for this context,
even if the big roll was a fairly expensive investment,
but it is an appropriate amount for use in the two polytunnels that I am growing in.
While the twine is used for most of the plants, I decided to also buy a trellis made
from biodegradable jute fibre, which is designed for peas and beans to climb up, but I wanted to
try to use it to grow a squash in the polytunnel. I've not had a lot of success with squash plants
in the polytunnel, mainly because they are so vigorous, and can take up so much space, and I
often grew them in the corner of the polytunnel up against the plastic to try to contain them.
This year I decided to try planting the squash in one of the middle beds of the
polytunnel, to hang the trellis from the polytunnel structure for it to climb.
Although I had to guide a few of the initial vines up the trellis, the plant did most of the work at
climbing to fill out the full section of trellis, and I only had to prune back the vines that were
growing away from the trellis, or crowding the adjacent plants. I was concerned that the weight
of the squash fruit as it developed would be too much for the trellis to support, but it seems to
be able to hold it all quite well even though the squash for this variety can get as heavy as 5kg.
I tried growing another type of vining summer squash in the other half of the trellis,
but it was not so successful, mainly because the plant was not such a great climber,
with the leaves closely spaced along the vines, so I will have to figure out some other method
if I grow this variety again. After harvesting the squash I could simply cut everything down,
and throw it all in the compost, but I'm planning to spend the time to pull all of the vines out of
the trellis, and to use it again next year, but it is possible that the twine will have
degraded in places, and that there is a risk of the heavy crop falling mid way through the season.
One of the other pieces of material or supplies that I have bought and stated using this season
are little clips specially designed for attaching tall plants to twine. I
have seen these things before, but have resisted buying them as I was generally content with using
the method of winding the plants around the twine as they grew. But these little clips are well
designed, gripping the twine quite securely, and easy to clip around the stem of the plant,
and they are quite easy to remove as well, either to reposition them, or to remove them for use
again. Apparently they are made from biodegradable material,
which means I could simply pull the plants out and throw the whole thing into the compost pile,
including the twine and clips. This would save a significant amount of time, and would obviously be
very useful for large scale growers, but I think I will try removing them for reuse next year,
putting in a bit of time in the autumn to save a bit of money, but also reducing the amount
of supplies that need to be manufactured and shipped to me. It will be interesting to see how
long these clips last, and how many times they can be reused before the risk of them failing
to hold up the weight of the plant becomes enough of an issue for me to replace them.
The other small type of equipment that I have invested in for this growing season,
are generally known as tomahooks. I had not known about these ingeniously simple bent pieces of
wire until a few people commented on my previous video about growing tall plants in polytunnels.
These are designed specifically to be able to easily hang from the support wire,
and to let out more twine as needed as the season progresses. Each hook needed to be wound
with enough twine to last the full season, which took a bit of time, but after that,
the hanging and dropping process I use to grow both tomatoes and cucumbers is quite a bit easier.
At the start of the season, I simply hang the hook on the wire above, unwind enough twine so that it
reaches down to the ground, and attach it to the stem of the small plant with one of the clips.
As the plants grow I continue to clip them to the twine, and when they reach the top of
the polytunnel space, I simply unhook it, let out a loop or more of the twine and rehang it
further down the wire. This causes the bottom part of the plant to lie on the soil surface,
but because the older leaves are removed from the base of the plants before lowering,
it is quite an easy process to keep the plants under control, especially with the cucumbers.
Last year I grew these plants as a single central vine which I allowed to climb the fixed twine,
over top of the support wire, and then hang down the other side,
a method that worked reasonably well but had a few issues.
But letting out more twine to drop the plants instead and laying the pruned part of the vine
on the ground, and continuing to move the top of the plants around the bed in a long circuit,
I found that it was a lot only easier manage, and the crop seems to be more successful.
And because the cucumber fruits form on the newer parts of the plants, they are usually kept up off
the soil, remaining clean and easy to pick, even in the shorter space of my smaller polytunnel.
Although I've used a very similar method of dropping and laying the vines of my tomato
plants in my larger polytunnel, I found that the growth habit of many of the more vigorous
varieties of tomatoes meant that the vines needed to be dropped before the fruit on the
lower trusses had all ripened. This made it harder to harvest the crop, with a lot more bending down,
and that a lot of the tomatoes ended up in contact with the soil, spoiling some of the crop. In my
other polytunnel I am dealing with this issue by hanging the plants at about waist height,
with several additional lengths of twine to support the overlapping plants in the air,
a process made easier with the clips. This means that the trusses of ripening fruit tend to hang
down below the more horizontal lengths of stem, which keeps the fruit cleaner, possibly allowing
them to ripen faster, and it makes them easier to harvest and they are quite beautiful, but it is
more work, and I am still looking for easier ways to manage these vigorous varieties. I am not sure
if this is an issue with the type of climate we have here in Ireland, with enough warmth to allow
the plants to grow, but not warm enough to ripen the fruit fast enough, but it is something that I
need to deal with. Grafting the plants onto other rootstock is a possibility that I'm interested in
exploring, but letting several side shoots grow in addition to the main stem might be a easier way to
restrict the height, even though each plant will need more space. But the easiest method would be
to simply prune the top of the plant when it hits the top of the polytunnel, and not worry about
dropping it at all, and accept whatever growth is there, which might be enough for the kind of
growing season that we get. I want to do side by side trial next year to see how these different
options compared to the drop method I have been using, in terms of both ease and productivity.
In the past I have tended to leave the eggplant or aubergine plants to grow as they naturally would,
without much pruning or training, but I haven't had much success with them, and often had issues
with moulds and mildews, likely exacerbated by the dense foliage and poor ventilation in the
polytunnel. This year I followed the advice of a few other growers and treated the aubergine
plants in a similar way to the tomato plants, pruning out all of the side shoots, and forcing
the plants to grow up one central stem. I also planted them closer together, clipped them to a
support twine hug from the polytunnel structure, and removed the lower leaves as the plants grew.
All of this, in addition to growing a better variety, has produced the best crop of aubergines
I have ever grown, turning a marginal crop into something that is surprisingly productive.
Even though the plants were transplanted late, and were badly affected by the aphids due to
the stress of the first part of the season, they are strong plants now, and growing quite tall.
And with lots of light and the air movement that is possible now between the plants
there isn't any signs of mildew or mould, and it will be interesting to see how
long into the autumn they will continue to produce. I tried similar approach with the
pepper plants in my other polytunnel, but I haven't been so consistent with pruning.
But with the success of the aubergine crop, I am now much more interested in finding methods
of pruning and controlling these pepper plants to get higher yields and better quality harvest
in the growing conditions that we have here in Ireland which are not really suitable for peppers.
Even though I have been growing in polytunnels for many years now, I am still learning a lot
about all of this. Part of it is simply doing the research to find out what works well for
other growers, and part of it is accepting that there are little pieces of equipment and materials
that I can buy that can make some jobs faster and easier and that can open up other possibilities.
I have generally resisted buying in specialised equipment like the clips and hooks, or even the
crop twine, partially because I like making do with what I can recycle and reuse or what is
widely available. But I'm also a bit hesitant in promoting the idea that you need to buy in these
specialised pieces of equipment or materials in order to successfully grow your own vegetables,
as I feel that this might create barriers that prevent people from trying things out, especially
when there are so many other options out there. I would definitely use this type of trellis again,
and a big roll of this crop twine has been a good investment for me, at least the scale
that I'm now growing at, as well as being a much better replacement for the plastic builders twine
that I had been using. I like the clips, which I think are quite ingenious and well designed,
though I suspect they are best used in conjunction with winding the plant around the twine,
so I can support the plants with fewer clips, and I wonder how many seasons I can get out of each
one before they degrade. And the hooks are quite convenient, and will likely last a long time,
and are also something that people can make themselves. But the benefit of these types of
supplies and equipment are really dependent on the scale of production, as at a smaller scale so many
other options are possible. But in all these cases I think that consistent care and attention of the
plants, as well as developing appropriate skills, have a much greater impact on the ability of a
person to be able to be get the most out of their growing space. But as I continue to grow more, to
establish additional growing spaces, and explore more of the market gardening scale of production,
these biodegradable options, and little things that I can invest in can save me a lot of time.
But only if they are paired with methods that work well for me, in the context that I'm growing in.