I have been doing quite a few trials of different varieties of vegetables, to both explore different
types, and to find varieties that grow better and produce more in this context.
After growing the same mainstream variety of climbing beans for many years,
I decided to grow 10 different varieties of this type of bean in one of my polytunnels.
It was not a very controlled comparison for a few reasons,
but I did learn about the different possibilities of this crop, and I was able to expand the types
of beans that I am interested in growing. And this past season I decided to do another
variety trial for this high value crop, where I tried to create more controlled conditions
so that the crops would be more comparable. Although the total amount that I was able to
harvest from each variety is a key consideration, I was also able to learn about some subtle
details that can make a significant difference when selecting which variety to grow again.
In the trial 2 years ago I grew the 10 different climbing bean varieties,
intercropped with a trial of different varieties of courgettes or zucchini.
This would have created variable conditions that would have distorted the results,
so this year I grew all the different bean varieties side by side.
In the previous trial I had not been able to include the main variety that I had been
growing for many years because of bad seeds, and this year I was able to compare it to
two other similar varieties that produce the very popular long green pencil shaped pods.
I also included a purple and a yellow long podded variety, even though have not been
very impressed with the similar coloured varieties that I have tried in the past,
and I included a short podded variety that I had grown in the previous trial.
I grew a few of the flat podded Romano type of beans 2 years ago, and had been very impressed,
but I had not been able to find seeds of the same varieties, so selected two others which
seemed similar for this year’s trial. And I included a variety developed for
harvesting semi mature seeds instead of the tender pods, even though this was not so
comparable with the immature pods that I planned to harvest from all of the other varieties.
Unfortunately, I didn’t save any seeds from the trial 2 years ago,
and I have struggled to find additional seeds from some of the varieties that I really liked.
So this year I decided to save seeds from all the different varieties, even though this would add
a complicating variable onto the trial, as it would likely affect how much the plants would
produce after the initial batch of beans. So I figured it was better to compare the
varieties primarily on the quality and harvest of the first flush of beans that were produced.
In total this year I grew 9 different varieties, 4 of which I had grown in a previous trial,
one variety I had grown for many years, and 4 varieties that I had not tried before.
I direct sowed seeds from all the varieties in the polytunnel bed in the middle of April,
sowing enough seeds to ensure there were 3 strong plants at each station that were spaced
40cm apart, in order to climb up the length of twine tied to the polytunnel structure.
I had 2 stations, or 6 plants for each variety, plus one extra column of beans at either end of
the row that I planted to produce dried seed from the variety commonly used for semi mature seeds.
I thought these extra plants were important so that each of the nine
varieties would be growing in similar conditions,
instead of having the varieties at the end having the advantage of extra light and less competition.
Early on in the season as the plants grew, I noticed the one variety had plants growing
a different way, with some plants climbing as expected, and others growing more as a bush bean.
There must have been a mixup in the seeds by myself or in the original seed package,
or some form of cross pollination, so I decided to drop this variety from the trial as it would
not have made an accurate comparison. But I left the plants in place to
maintain consistency for the other varieties. So that left 8 varieties in the trial, 5 with
long pencil type pods, 3 green, one yellow and one purple, two with the flat Romano type pods,
and one for fully developed fresh seed, and the same variety for dried seed at either end.
Looking at the harvest from the first flush of beans, there is significant difference
in yield between the varieties, which was also very apparent while harvesting.
Two varieties clearly produced a lot more than the others, including one of the three green
pencil varieties, and one flat Romano type. The Borlotto variety had a very low yield,
even thought the pods were harvested only when the seeds had reached their full size,
and this included the weight of the pod which was no longer edible, so it is not really comparable,
but perhaps a useful reference for the future. These semi mature beans were harvested all at
once more than a month after the harvests of the other varieties had started, so although they are
nice to have, I am not sure they are really viable to grow in this context, especially
as the tender pods of the other varieties are much more popular and more productive.
The yellow and purple varieties are easiest to see and harvest among the green foliage,
but they produced significantly less than the other varieties.
Although I wasn’t impressed with these,
the different colour and shape of the pods can be attractive,
I just wish that the purple didn’t turn into a more conventional green when the pods are cooked.
The three green pencil type varieties all had very similar pods, and they all produced similar
black seeds when mature, so they seem to have been developed from similar origin varieties.
These three varieties had decent yields, though a variety sent to me by another grower produced
more, the variety I had grown for years had produced less, and the one I had selected from
the previous trial was in-between the two. One of the flat podded Romano varieties also
produced a high yield of large, easy to harvest pods, but the other one produced a lot less.
I didn’t notice any difference in taste between the three varieties that produced
very similar long green pencil shaped pods, which were all essentially stringless,
so the difference in yield becomes a much more important factor, but it is not the
only basis for selecting between the three. The Emerite variety that produced the most,
grew pods on stems that were significantly longer than the other two, which made the pods a bit
easier to pick and less likely to get caught up in the vines as they wound around the twine.
A few of the pods of the Fasold and Cobra varieties had rotting tips,
and some places where mildew or some other disease had affected the stems,
but I didn’t notice any of this with the Emerite variety.
This wasn’t a significant issue this year, but better disease resistance may be an
important factor with other growing seasons. With the two Romano or flat types of beans,
the Helda variety that had the higher yield had slightly flatter pods which
I think is interesting, and I think I liked their flavour more.
The lower yielding Eva variety had shorter stems, so the pods were closer to the climbing vines, and
there also seemed to be a few pods with rotting ends, which I didn’t find on the Helda variety.
So the two varieties that produced the biggest crop also seem slightly
less susceptible to disease, and had longer stems making the pods a bit easier to pick.
Neither of these are enough on their own to select a variety, but they
reinforce the decision I might make to grow the varieties again based on their higher yields.
But it was interesting that the Fasold plants were noticeably lighter at top, and they didn’t
seem so aggressive or tall, producing fewer pods higher up, which made harvesting easier.
These plants would not over shadow other crops as much,
especially compared to the more vigorous Emerite variety, which could be useful
in some contexts, enough to possibly select this shorter variety instead.
Looking at timing of harvest in a bit more detail, all three of the green pencil pod
types were quite early and started to produce at the same time, 69 days after direct sowing.
For the first 4 harvests the Fasold variety was producing significantly more pods than other two,
producing a lot more beans earlier, but then slowed down for the last 3 harvests.
The lower yielding Cobra variety almost caught up a bit later, but the higher
yield produced by the Emerite variety was mainly because of the last three harvests,
producing a bigger yield over a longer period of time.
Part of this is due to the six days between two of the later harvests,
rather than 3 or 4 days that separates the earlier harvests, and this delay would cause
the larger pods to grow even bigger, leading to a greater weight from the same number of pods.
And this seemed to boost the yield of the Emerite variety which was producing more
pods later in the harvest period, but didn’t really affect the Fasold variety
which had almost finished producing pods by then. This might not account for the full difference in
yield between these two varieties, but it would definitely reduce the difference between them.
The two flat podded varieties both started producing pods a bit later, with a slower start,
and didn’t produce large yields until about 10 days after the three earlier varieties.
The pods available to harvest from the Eva variety trailed off fairly quickly,
but the Helda variety continued to produced a lot of pods,
ending up with relatively high yield of pods over a shorter harvest period.
I left quite a few pods at base of plants of all of the varieties so that they could continue
to develop mature seeds for seed saving. I removed the leaves from the base of the
plants to let the sunlight in, to help the pods dry and most of them were dry enough
to pick within 3 and 5 weeks after the last of the first batch of pods were harvested.
I ended up with a lot of seeds from all 8 varieties, more than enough for several years
planting, and to share with others, even from the varieties that I will likely never grow again.
If I wasn’t saving any seeds from these plants, or waiting for another flush of beans to develop,
a different crop could have replaced these bean plants in the middle of the summer,
and this is the cost of waiting for seed saving. But I was also waiting for the Borlotto
variety of pods to dry at the two stations at either end of the row,
which ended up producing almost one kilogram of dried good quality seeds for use in the kitchen.
This seemed like a fair amount, but I really don’t have anything compare it to, because I don’t have
any experience with dried beans, but I could have grown almost 4-5kg of fresh bean pods which are
perhaps more valuable in the same space, so it really depends on the context and what I want.
A big factor that I did not explore this year is how many beans would all these varieties have
produced as a second flush or batch, if I had not left so many of the pods for seed saving,
and how the timing of the later harvests would compare between the different varieties.
I had essentially abandoned this plants while I was waiting for the seed saving pods to dry,
and when I finally returned to them I was surprised by how many additional
pods were produced on some of the varieties.
But many of them were already past their prime, so I could not really compare them,
but for a few varieties it would definitely boost the overall yield quite a bit.
With other varieties, these additional pods seem to develop quite a bit later,
and the delay might not be worth the wait, and it may be better to remove
the plants immediately after the first flush of beans, and replace them with another crop.
But that depends on the context and how intensively I want to manage a high value
growing space like this, and it would be interesting to compare the productivity of
these different varieties if I had left them in the ground for a longer growing season.
After this second trial of climbing beans, I think I am not really interested in growing
purple or yellow varieties again, unless I wanted that additional
diversity of shape and colour in the kitchen. And I would not grow the shorter podded variety
that seemed to have had mixed up seeds. The Borlotto variety is nice to grow for
both semi mature and dried seeds, but I’m not sure it is worth taking up valuable
polytunnel space for growing a lot of them. It would be interesting to try growing some
of these other varieties primarily for dry seeds, and for semi mature seeds,
to see how they compare to a variety that was bred for this, especially if they could grow outside.
The Helda variety is definitely one of my preferred beans from this trial, as it produced a
good crop of really nice tasting beans, and was a lot more productive than other flat variety.
I am no longer impressed with the Cobra variety that I have grown for so many years,
and it makes sense to replace it with the Emerite variety, with its higher yield,
and perhaps better disease resistance, and longer stem that makes the pods a bit easier to pick.
But I also like the shorter and less vigorous plants of the Fasold variety, which I
think it would be more appropriate in a crowded polytunnel, and there could be a benefit with
the slightly faster cropping from this variety. So I will definitely be growing Helda again, but
I am still undecided between Fasold and Emerite, but the differences between these two varieties
is really quite subtle, and either of them would be good enough to continue growing again.
And I have enough seeds saved from all of them to grow for quite a few years,
plus a lot to share with a lot of other people.
So I think this is a good result from a successful variety trial, but it would be good to further
explore how many beans some of these varieties would produce over a longer part of the season
and if I hadn’t left so many pods for seed saving. I also want to continue to grow a broader range
of climbing beans types, to continue to explore different tastes and textures,
and possible uses in the kitchen, and to see if any of these varieties of climbing beans
will successfully grow outside in this windy maritime climate that we have here in Ireland.