When selecting things to grow in the gardens, I tend to lean towards types of vegetables and
different varieties that are vigorous and robust. I think a lot of this is simply based on the idea
that strong is better, that robust and vigorous plants are better able to get
what they need from the soil, to grow quickly and to produce an abundance.
And these are things that I want to get out of the gardens most of the time,
and in a many of situations more vigorous plants can be really beneficial, but I am learning
that it really does depend on the context. For example, I have been exploring a diverse range
of courgette or zucchini varieties for growing in the sheltered conditions of the polytunnel.
And some of the varieties grew way too big, and I had to stop the trial early,
but I did find a few interesting possibilities in varieties that are the opposite of vigorous.
In the vegetable gardens there is often a struggle to find a balance between growing as much as
possible, and giving individual plants more space. This is one of the key differences between some of
the family scale gardens that I am trialing, with some focusing on productivity through
higher density planting, and others allowing enough space to ensure plants are not stressed
or struggle with too much competition. In the polytunnels, I generally try to
get a much out of the high value space as I can. But within this sheltered and warmer microclimate,
the plants can get too big, and I often rely on pruning and controlling the
plants in particular ways so that they do not overwhelm each other and take over the space.
And this is something that I have done in the past with courgette and zucchini plants in the
polytunnels, pruning the older leaves, cutting out any side shoots, and trying ways to support
them vertically so that they will be able to produce an abundance for longer in the season.
I have been growing the same hybrid variety of courgettes for a while now,
one that I originally selected more by chance than anything.
And I have continued to grow that one variety year after year in all the gardens, mainly so that it
would be easier to compare the harvests and issues in different gardens and in different years.
But I have wanted to explore other varieties, to better understand the differences between
the different types, and it is unlikely the variety that I randomly selected a
couple of years ago is the best for this context, especially in the polytunnel.
Two years ago I bought seeds for a load of different courgette varieties, both hybrid,
and open pollinated, some conventional, and some quite unusual, and I planted one of each variety
as an intercrop between climbing beans. It wasn’t the best context for a trial,
but I learned a fair amount and wanted to repeat the trial with a slightly reduced selection of
varieties, to better understand the possible range, and how they grew, their habit or form,
the taste and how productive they can be. I wanted to find varieties that work in the calm
and warmer microclimate of the polytunnel, which I can control effectively so that they didn’t
take over the space, and produced a high yield of the types of courgettes that people like to eat.
I sowed the seeds on the 21st of April, and transplanted the courgette plants of 9 different
varieties into the polytunnel bed a couple of weeks later, spacing the plants about 1m apart.
I let all of the plants grow without pruning the older leaves, or removing any side or
secondary growing shoots, to see how they would develop, but I regretted that decision later.
All the plants grew well, and the first smaller courgettes were harvested from some of the plants
44 days after sowing, while other varieties didn’t produce any fruit until day 56 or 57.
The standard Ambassador hybrid variety that I typically rely on, grew as I have come to expect,
producing typical shaped courgettes, on a plant with a fairly open habit which makes
it easy to see and harvest the developing fruit. This plant grew an additional side shoot and had
a decent yield, producing a reasonable number of fruit, which sets a baseline that I am use to.
The Atena hybrid variety had more of a trailing or vining habit, with two main vines developing quite
quickly, which did take up a fair amount of space, though not as vigorous as some of the others, and
it produced a greater number of yellow courgettes, and a really high yield from the two vines.
The open pollinated Genovese variety had a shorter vine, with long stems to the leaves
creating a large open bush form to the plant, and it produced a good crop of pale green courgettes,
with a similar yield to my standard variety, which I thought was quite
good for an open pollinated variety. Another yellow hybrid, called Gold Rush,
was more compact than the other yellow variety, and was definitely a smaller plant that seemed to
fit in better to the space it had, but produced a small yield with fewer courgettes to harvest.
The Midnight hybrid variety produced a consistent crop of dark skinned conventional shaped fruit,
and was also more of a compact plant, with one vine and the leaves were not spread out so much,
but it produced an impressive number of nice sized courgettes, and the highest yield by a little bit.
The Piccolo hybrid variety was definitely more of a vigorous vining plant, which quickly grew too
large for the space and the support I tried to give it, and a lot of the unusual ball
shaped courgettes remained hidden until they got quite big which pushed up the yield quite a bit.
The open pollinated Romanesco variety was definitely the largest plant in the set,
producing several strong vines that occupied a lot of the space, overshadowing adjacent plants,
and I ended up pulling up the plant a month before the others, but up to
that point it was more productive than most of the other varieties.
Another open pollinated Striato d’Italia was relatively compact, but had a lot of leaves
and side shoots that crowded out the centre of the plant, which made it difficult to find
all of the distinctive patterned fruit before they got too big, which led to a higher yield.
The last plant Sunstripe, was also a hybrid variety that produced a later
crop of distinctive yellow and white striped courgettes, and was more of a vining plant,
though the main stem split mid way through the season, which contributed to the lower yields.
This bed of courgette plants definitely got out of hand, with the plants extending into
the paths, making it hard to get around, and impacting the bean plants in adjacent bed.
This made it harder to evaluate the some of the varieties,
especially the ones that were overly impacted by a more vigorous neighbour, and most of the
plants would probably produce differently if they were pruned and controlled a bit.
I usually do a fair amount of pruning to remove the older leaves of the courgette plants in the
polytunnel to reduce the size and weight of the plants, remove leaves affected by mildew,
and to increase airflow around the base to avoid some of the stem rotting that often occurs.
I have also tried several different ways to train the main vines vertically up twine or posts,
though I am usually not consistent enough with this for it to be effective, and I wonder if
it would work better with different varieties. I did put in a few bamboo canes to support the
growing vine of some of the different varieties in this trial, but it was not really effective,
at least not without tying them up and pruning some of the older leaves
And the vines of some of the varieties grew way too long for this kind of support, and
would have needed to have been tied to a strong twine suspended from the polytunnel structure.
I usually remove most of the side shoots from the general crops of courgette plants, and this would
have changed things quite a bit in this crop, as the bed would not have been so overcrowded.
In another trial in the same polytunnel this year, where I was seeing what happens to the
plants when I harvested the courgettes at different sizes, I found that the smaller
I harvested the fruit, the larger the plant grew, especially with additional side shoots.
And it was really interesting that the plant that had been left to grow large marrows was
quite small and manageable in comparison, so that is definitely something to consider.
I had also tried growing some patty pan summer squash plants in the corner of the polytunnel,
which I have never grown before, and the plants grew way too big,
with a really crowded centre that made finding all of the immature squash very difficult.
This was very similar to the habit of the Striato d’Italia courgette variety,
which seemed to increase the amount of mould that developed in the cramped inner part of the plant,
and I suspect varieties that grow in this way are much better suited for a larger space outside,
and probably in a warmer and drier climate.
So the more vigorous varieties were not very useful in the Polytunnel,
and the varieties that grew much longer vines would need to be tied up vertically in some way.
And it would be preferable if the plants had a more open habit or space within the leaves,
as this would help to increase the airflow and reduce the possibility of moulds that can be a
problem in the still air of the polytunnel, and it would also make it easier to harvest.
This was a small trial, with only one plant of reach variety,
and in a particular context, so things could change quite a bit with another trial.
But, I was quite surprised by the results, especially with the Midnight hybrid variety,
which produced the most number of courgettes, with the biggest total weight, of the type of
courgettes that many people seem to prefer. And this was when the plant was overcrowded
by a more vigorous neighbour. The significantly higher number
of courgettes that this plant produced works well with my preference to harvest small courgettes,
and the plant was quite small, with the leaves not extending too far out to get in the way.
This also means that it was not so open in habit, and would make it a little bit more
difficult to harvest, but as the plants would be smaller, I would probably be able to plant
them a little bit closer together, which would probably increase the yields a bit.
The Atena hybrid variety was also very impressive, with lots of fruit and a high yield,
though it would be interesting to see how this changes if there was only one vine.
The longer vine on this variety would probably benefit from being grown vertically up a twine
or post, and pruning the older leaves would help to reduce the impact of the
larger diameter and the weight of the plant that had to be supported.
And I was also impressed how the open pollinated Genovese variety produced
quite a few really nice courgettes, though not as productive as the two hybrid varieties,
and this plant was not so vigorous, and fairly contained, despite its long leaves and open habit.
In this context of growing in the polytunnel, I think I would grow the two hybrid varieties
Midnight and Atena, as well as the open pollinated variety Genovese, as they all did well,
and the different colours and textures of the courgettes make a really interesting combination.
If I had to pick one, it would definitely be the Midnight variety mainly because
it seemed to be so productive for a plant that was so small.
But it will be interesting to see how all these three of varieties produce when they
are not suffering from the competition of the more vigorous neighbours beside them.
I think the two larger varieties would probably benefit from the pruning and staking to control
their growth so that I can get the most out of these plants, without them getting in the way.
But with the Midnight variety I think it would do well in this kind of context
without these extra tasks, to just let it grow without controlling the plant too much,
which could save a fair amount of work. But then it does depend on how long I want
to grow them for in this context, as there is a benefit from pulling the crop of courgettes out
of the polytunnel once the plants outside in the gardens start to really produce,
and then to replant with another crop later in the summer that will be able to produce well
into the autumn, rather than trying to to get one plant to produce for the entire long season.
It will be interesting to try growing all of these varieties outside, and I might choose
different ones, especially in the context where I can give each plant a lot more space.
I suspect that I will end up replacing my usual variety that I grow for
another variety in the outside gardens. And it will definitely be replaced for
the plants in Polytunnel, especially after I have seen what other hybrid
and open pollinated varieties can produce. But I am surprised that a smaller variety that was
apparently bred for container growing comes out as the most appropriate choice in this context, but I
guess within the warmer climate of a polytunnel, even a smaller variety can be vigorous enough.
The growing season is finally starting to come to an end here in Ireland, and it is really
good to be getting through a backlog of videos that I’ve wanted to make after a busy summer.
There is so much more that I learned and explored this year that I want to share,
and we are starting to do the work to overwinter the gardens and preparing for the
next year of this independent research project. I wanted to thank all of those people who leave
comments and share the videos that I make, and especially want to thank all those people who
continue to support me, this channel and the broader RED Gardens project through
regular donations and contributions with Patreon and one off donations with Paypal.
It would not be possible to continue with this project without all of you.
If you want to join them, there are links to Palpal and Patreon on screen, or in the
description below, as the more support we can get, the more we can explore and share with everybody.
But most importantly, thank you for watching.