Since I was I kid I've known about the crazy abundance of zucchini plants,
and about all of the jokes of growers desperately trying to give away their abundance,
especially when don't harvest in time and let the zucchini grow way too big. Here in Ireland these
plants are called courgettes, or marrows when we intentionally or unintentionally grow much bigger
samples, and their potential abundance is quite amazing even in this cooler maritime climate.
It's one of few crops where can be both delighted and overwhelmed when it produces a huge amount and
sometimes it can be such a struggle to keep up with the abundance that we're actually relieved
when the season comes to an end. So the aim with growing courgettes is not necessarily to get the
biggest possible yield out of the crop, but rather to manage the plants in such a way that we can get
the most out of them over the full season, which I think is a subtle but important distinction.
One of the main things that I do in order to get the most out of courgette or zucchini plants
is to harvest the fruit that they produce quite regularly and
more importantly to harvest everything that was ready to pick even if there is too much.
I used to get caught in the repeating cycle of harvesting only the largest of the courgettes
that were in the gardens, even if there were also ones ready to harvest that were the closer to the
size that I would prefer to eat. But the next time I went out to the garden, those perfectly sized
courgettes that I had left behind the last time, had grown larger than I would prefer,
but I would harvest them anyway, and again leave other ideal sized courgettes behind.
And we could go weeks trying to eat our way though too many over-sized courgettes, that
we didn't like nearly as much, mainly because I didn't want to waste any, and in the end we would
end up not enjoying the crop nearly as much as we could have. These days, I think a much better
method is to harvest the courgettes that are the size that I want to cook with, and anything that
is larger is also removed and simply added to the compost, if I can't find someone else to pass them
on to. And this breaks the cycle of trying to to continually catch up with the excess production.
Although I still struggle with the idea that this is a waste of potential food,
I try to stick with the policy of discarding or composting anything that is too big, as I think it
is the best option in the long run, simply because we are less likely to get fed up with this crop.
Trying to get the most out of courgette plants in this climate means I also have to deal with
a relatively cool growing season on a fairly windy site, with the risk of frost killing the plants at
both ends of the season. We typically have periods of warm and sunny weather in the spring and early
summer that I would prefer to take advantage of, but there is also a risk of late frosts
up until the end of May. Rather than wait until after the last expected frost date to transplant
these frost tender plants into the gardens, I've been planting them earlier in the season,
and covering the beds with one or two layers of crop cover or horticultural fleece. And I also
place a few large containers or buckets of water in beside the plants to serve as a thermal mass,
absorbing the warmth during the day to be slowly released overnight. And this has worked really
well to protect the plants from frosts, and it shelters them from the strong winds that we
tend to get. As a result, the plants tend to grow much faster in the sheltered conditions, but that
means that they start flowering earlier, which is a problem if the covers are prevent the honey
bees or bumble bees from getting in to pollinate the crop. So either I need to remove and replace
the crop cover every day, and possibly take on the task of pollinating the flowers myself,
or I could miss out on the possibility of a significantly earlier crop, if the weather
turns cold at the wrong time and I've started the plants quite a bit earlier in the spring.
Pollination can also be an issue with courgette plants at other times of the season,
which requires honey bees, or bumble bees or some other type of pollinator
to transfer pollen from the male flower to the female flower. Most
of the time there are more than enough pollinators around here, but this isn't always reliable,
and I have ended up with distorted and rotting courgettes because they were not pollinated. This
past few seasons there were significantly fewer bumblebees around for some reason, and the honey
bees from the nearby hives didn't seem to be interested in anything in the gardens. And
this led to more unpollinated fruit than in the past, especially at the end of the season. In
addition, the plants seem to produce fewer male flowers at the start of the season and especially
at the end of the season, which definitely caused the harvests to drop off quickly in the autumn.
I don't know if this is a particular issue with the variety of courgette that I'm growing,
or due to the weather becoming colder at times, or because of some other factor,
but it's definitely something that I want to keep an eye on next year.
I can get around these issues to a certain extend by hand pollinating the female flowers with any
male flowers that I can find, but this is an extra daily task that I often forget to do.
The other obvious thing focus in trying to get the most out of these courgette plants
is to make sure that the plants are strong and healthy for the full growing season.
Of course a big part of this is providing enough soil fertility for these hungry plants,
and the obviously healthy plants in some of the gardens, compared to the relatively poor growth
in others indicates to me where I need to focus more efforts on building soil fertility. But
all of the courgette plants could probably use some supplemental liquid feeding later
in the season to ensure that these plants don't run out as they continue to grow.
I suspect that some of the diseases that develop, including the powdery mildew that commonly forms
on the older leaves, are at least partially due to imbalances in the soil fertility. More
recently I've been focussing on reducing the overcrowding of the plants,
and removing any diseased leaves as a way to maintain the health of the plants. I
have been cutting off and removing older leaves, and in some cases pruning them back quite hard
and leaving only the leaves towards the growing tip of the plants. This
pruning does remove a lot of the mildew infection from the plants, and it also opens up the space to
allow more air movement, and lets more sunlight into the actively growing parts of the plants,
and in some cases it might make it easier for bumblebees to find the flowers. But there's also
the possibility that removing these older leaves will reduce the stress on the plant in other ways,
or at least encourage the plant to focus available energy, nutrient and water resources on the more
actively growing parts of the plant, but this is something that I'm only beginning to explore.
It will take a lot more experimentation to figure out how much pruning to do, how much of the plant
to remove, and how frequently to do it in order to have the greatest benefit to the plants. In
the Polytunnel Garden this season I pruned the courgette plants quite aggressively, in order
to prevent them from taking up too much space and overcrowding the bed and the other crops.
I have also had issues in the past with the stems of the plants rotting, likely due to
higher humidity and the lack of air movement, with the plants suddenly collapsing and bringing
a sudden end to the harvests in the middle of the season. The pruning seemed to have helped, though
it hasn't completely solved the issue, as I still lost a few plants in the Polytunnel this year.
I've also decided to try training the plants up sticks, to allow them to grow vertically
instead of spreading out over the ground. This involved regularly tying up the top of the plant,
a task that was tricky in amongst all of the large leaves, and even more difficult if I left it grow
for too long. Tying the plants up like this, in combination with a regularly pruning the leaves
created a very different growth pattern, with an upright long stem topped by a cluster of leaves,
flowers and courgettes, almost like a palm tree. This technique was definitely a lot more
work, but it allowed some of the plants to last a long time in a relatively confined space. The
more successful of these plants were sown in the beginning of April, transplanted into the soil of
the Polytunnel at the beginning of May, with the first harvest at the beginning of June, and the
plants still producing courgettes into the second week of October. This is an eighteen week long
harvest period, which is definitely a record for me, and I might have been able to start it earlier
and it could have gone on for longer if it wasn't for the lack of pollinators and male flowers,
but by then the growth had definitely slowed down anyways due to the cooler weather.
Each of these courgette plants in the polytunnel produced about 12kg over the full season with
over 40 courgettes harvested from each plant, not counting the ones that were not pollinated. That
works out to about 15kg per square meter of growing space,
which is a huge yield of good quality courgettes, harvested over a long period,
which is what I wanted from these particular plants. But it did take a lot of work, and
occupied valuable growing space in the polytunnel, and I'm not sure it is necessarily worth it,
especially as I can grow an abundance in the outside without so much work.
It would be a lot easier to simply plant these plants out into the gardens after the risk of
frost has past, to give them lots of space to grow into, to simply compost and any surplus of overly
large courgettes, and to accept that there's a relatively short season to this summer vegetable.
But it is interesting to see how these plants can be encouraged to produce more, in addition
to providing these hungry plants with lots of food and water throughout the growing season.
Providing protection from the colder weather in the beginning and at the end of the season
definitely helps, and they really grow well in the protection of the polytunnel.
Pruning the older leaves seems to help quite a bit, and I'd like to do side
by side comparisons in the future, to figure out just how beneficial it is and how hard to
prune. Making sure that each flower gets pollinated is perhaps more difficult,
as I'm depending on the apparent rise and fall in the interest of local pollinators, or I need
to take on the take on the task of pollinating by hand. And I'm not convinced that training
the plants to grow vertically up sticks or other support is worth the effort, but it is something
I am going to continue to explore next year, as it seemed to help produce an abundance this season,
and it prevents the plants from getting out of control in the tight space of the polytunnel.
But I still feel that the biggest factor is managing the potential abundance by harvesting
very regularly, as this means that we don't get fed up with the corp, and we don't end up
with too many huge marrows that we don't want to eat. I know I was successful this season as I was
actually disappointed when the harvests started to slow down in the autumn, and this was despite
having had a great crop over a long season, and that was a significant change from previous years.