Last year I decided to grow bush beans in the polytunnel for the first time.
I have grown the climbing types of this green, French or snap bean for many years,
but I had not grown the shorter bush varieties before.
And instead of starting small, and getting use to the crop, I decided to do a variety trial,
which meant growing quite a few bean plants from 15 different varieties
This was a lot of plants to start with, but I ended up learning a lot about growing bush beans,
especially that they don’t seem to be able to support their own weight, at least when
the plants grew larger in the polytunnel. And this created an unexpected hassle in
harvesting, and compromised the variety trial. But this year, working from the suggestions from
a bunch of different people, I built frames to support the plants, which worked really well.
In hindsight I should have done some more research last year about growing these types of plants,
as I would have come across suggestions for how to make sure that they remain upright.
Some people grow varieties that seem to produced most of the pods all at once, and they simply
pull the whole plant out of the ground, pick whatever pods are usable and compost the rest.
This would make things a lot easier, and would work with some of the varieties that I grew,
but not with the varieties that produced pods over a longer period of time.
Another option would be to earth up the row of plants when they are still fairly small,
relying on the mound of soil piled up along the row of stems to help keep the plants upright.
Another option would be to put posts in at either end of the row and to wind twine back
and forth between the plants to help support them. And a few people suggested that I use a grid of
rebar or a cattle panel, or some other grid, that could be supported up off the ground,
and the plants could simply just grow up through the holes.
And it was a variation of this option that I ended up trying this year.
I felt that the Rebar grid would be too heavy and a bit expensive, and the cattle
panels that people use in other countries don’t seem to be available here in Ireland.
But I did have some damaged Harris fence panels,
which are usually used for security around construction sites.
I have had a bunch of these fences, which had been abandoned because they were already starting
to break up the joints, that I realised I could re-purpose into something similar.
I have used them for a number of years to help support runner bean plants in the gardens and as
temporary windscreens, but they were gradually falling apart and my efforts to reinforce
or repair the corners didn’t work out. And I figured I could remove the wire
mesh from the pipes, and cut them to size with an angle grinder.
And I could cut out some of the wires to create larger holes for the plants to grow up through,
and for me to be able to get my hands in for harvesting.
The first task was to dismantle the panels which
was a bit difficult as I wanted to use the full height of the welded wire mesh,
as this would fit nicely with the size of the standard planting bays of the polytunnel.
I tried a few options but found that the small weld that fixed each wire to the pipe could be
broken off with an old screwdriver and hammer, and it was a lot easier on my hands when I used a pair
of fencing pliers to hold the screwdriver. It took a bit of time to break each of the
welds but in most cases the wire came off fairly cleanly.
Instead of cutting these panels into flat sheets that would have to be supported on posts or pegs,
I decided to cut the panels quite a bit wider and to bend down the sides so that
they would be self supporting, and so that they would also stay more rigid across the span,
and would be less likely to sag. I created larger holes by cutting
two out of every three cross wires on the top of the panel with an angle grinder.
And I cut out wires to create bigger holes on each side so that I could reach my hand
in from either side when weeding and harvesting. I wanted the width of these panels to be as wide
as the typical beds in the gardens, but I wasn’t sure how high off the ground they should be.
But I cut the panels to what I figured would be an appropriate size, which allowed me to get
two pieces out of each fence, and to stay away from the damaged end of some of the metal mesh.
I left stubs of wire along the sides that would be able to stick
into the soil to help hold the panels in place. And once it was all cut to size I used a piece
of wood to help me bend the sides up, and once flipped over the support frames were ready to use.
And with a bit of adjustment to the sides, the frames could be stacked together for storage.
The idea was that these panels would
simply be placed over the bed of plants when they’re quite young,
and as they grew the plants would naturally find their way up through the holes and be supported.
And with most of the batches of beans, I got the frames cut in time to simply place over
the developing plants, and the extended wires at the base stuck into the soil to keep it in place.
But with a busy summer I didn’t get around to making all the panels until
some of the plants were already too large. With these batches it took a bit of care
to slowly lower the frame over the plants while working to help the leaves up through the holes.
But as the plants continued to grew they naturally came up through the holes,
and I was pleasantly surprised how well it all worked for keeping the plants upright.
This made harvesting a lot easier and faster, and I was able to find almost all of the pods.
And because it was all easier, I ended up harvesting more frequently,
and was able to pick most of the pods when they were at their best quality.
When the plants fell over with the crop last year, a lot of the pods ended up touching the soil,
causing a fair amount of damaging rot, and increased the amount of mildew in the leaves,
stems and pods with a lack of airflow between the plants,
and I also damaged quite a few of the plants by lifting and moving them in search for the pods.
This year, none of the plants were damaged, all of the pods were kept off the soil
and were a lot cleaner and easier to harvest, and there was a lot less mildew.
There was some mildew with a few of the varieties, but that was more due to the humid conditions of
the polytunnel, and the susceptibility of that variety, rather than poor support for the plants.
And the wire frames kept the huge courgette or zucchini plants in the
adjacent bed from invading the space of the beans.
The bush bean trial last year was with 15 different varieties,
and I sowed each of the plants farther apart than usually recommended as I
figured they would get quite a bit bigger in the polytunnel.
They did grow bigger but I think the wider spacing was part of the problem
as if they were closer together the plants would possibly hold each other up more.
This year, I planted only 10 of the varieties, giving each set a 2 meter
section the side bed of the polytunnel, and I planted them closer together.
But instead of planting them all at once, I direct sowed each variety into the bed when
the different fast growing spring crops that occupied the bed were finished.
This staggered sowing isn’t ideal for comparison purposes of the variety trial,
but it fit in better with the availability of the beds in the polytunnel, and I didn’t want the
beans to be ready to pick all at the same time. I figured staggering the sowings over 4 weeks
would spread out the time needed to harvest all the beans and
prevent too much of a glut at one time. Apart from the different sowing dates,
the frequent harvesting of all the pods, and no damage to the plants
made it a much more successful trial of the different varieties this year, and allowed me
to get a better understanding of the differences between these plants, which is what I looking for.
In order to ensure that I have enough fresh seed from each of the varieties in case I
wanted to grow them again, I had decided to leave all of the pods on few of the plants for
seed saving at the end of each section or variety. This created a bit of hassle when the other plants
from that variety were finished, and I wanted to remove them in order to sow a replacement crop.
It was a bit of a hassle removing the plants without moving the support frame,
as I didn’t want to damage the plants still growing the pods for seed saving.
But there was enough space to clear everything out and to prepare the beds and sow rows of lettuce
for a cut and come again crop after the beans. I probably could have carefully removed the
wire frame, and supported the seed saving plants with canes,
or I could have waited until the pods were dry enough before clearing the entire bed.
And in the future I will probably not save seeds from the same batch like this,
to avoid this kind of complication, but the pods on these plants were dry enough to collect
and the frame could be removed before the lettuce had grown large enough for the first cut.
With some of the batches that were finished earlier, I was able to move the support frames
directly onto another bed where I had sown a second batch of 4 of the bush bean varieties.
With these I had decided to direct sow three rows of plants, rather than two,
in order to see how much more productive the crop could be in these conditions, and these
plants are growing well, starting to produce pods, and fully supported by the wire frames.
There are still two varieties from the first batch of plants that I have left
in place to produce a second flush of beans. These plants have became significantly bushier,
which made searching for the pods a bit more difficult, but the wire frame kept all the plants
well supported and allowed some air flow between the plants which are all in good condition still.
And I was surprised how much was produced in this second flush of
beans about 4 weeks after the last pods of the first flush had been harvested.
I wasn’t so sure that the investment of
time and material to make these support frames would be worth it
As usual it would have been better to make one or two of these frames to try them out this season,
as these types of equipment or infrastructure don’t always work out the way I hope they will.
But I went ahead and built 10 of them, and overall I am quite pleased at how
well these simple support frames worked for these bush bean plants in the polytunnel,
but they will only really be worth the effort if I use them for several seasons.
They should last quite a few years, especially if I can keep them dry in the winter,
and it helps that they are stackable so that they will take up a lot less space in storage.
Despite the success of this variety trial,
I am not sure I will continue to grow so many bush beans in the Polytunnel like this,
as I find the climbing varieties are much more productive and easier to harvest.
But we have had some success in growing them in the outside gardens, so I think next year I might
try a variety trial of bush beans outside, and these support frames will come in handy again.
But I think they will only really be worthwhile if they can be used for other crops at other
times of the year, including perhaps using them to support fleece or other kinds of crop covers
to keep material up off of low lying plants at cold and windier times of the year.
I think the frames may also work well to support some herbs like basil, or when seed saving from
some of the leafy greens like rocket, to help keep the tall stalks of seeds off of the ground.
They might also be useful for growing pickling cucumbers, where the vines can grow over the
top of the wire mesh, and the cucumbers can hang down below for easy harvesting.
And they could be useful for growing determinant tomato varieties, where
the fruit on the sprawling stems could ripen without coming into contact with the soil.
But this is all to be explored in the future, I just need to find
good uses for the pipes as well as the hundreds of pieces of wire that I cut out of the mesh,
in order to completely repurpose the original damaged security fencing.