Wednesday 29 June 2016

An uneven distribution

I have been looking closely at my tall "De Monica" Broad Bean plants. I have observed that the conversion of flowers into actual pods has been very uneven. Down at the bottom of the plants the set (formation of pods) has been pretty good, with lots of pods forming, but higher up, there are very few pods.

The formation of pods is triggered by the pollination of the flowers, in turn occasioned by the visits of bees. So why did bees visit the lower-down flowers but not the high-up ones? Are they afraid of heights, I ask?! My theory is this: the lower-down flowers appeared first, when the weather was reasonably good, and they opened out fully allowing easy access to the bees. However, at the time when the upper flowers were out the weather was appalling and the heavy rain reduced many of them to a soggy mess, and the bees just couldn't get in to pollinate them.

I think my theory is confirmed by the fact that the very much shorter "Robin Hood" beans have experienced the same effect - lots of pods down near the ground; few pods up above. It's a timing issue, not one of height.

The good news though is that the later-developing "Masterpiece Longpod" plants seem to be forming a lot more pods higher up.

They may have got in just in time, because the absolutely torrential rain we had on many occasions last week would have destroyed any flowers that were open at the time.

I have also come to the conclusion that it would be better to space my Broad Bean plants a bit further apart. This year I have two rows, each of 12 plants, in a bed which is 2.4 metres long - so in other words the plants are roughly 20cm apart. This means that their leaves are inter-twined, which may make it harder for bees to navigate between them, or even to detect the flowers in the first place. Next year I might try growing fewer plants at a wider spacing.

I'm going to continue to grow them tied to individual canes though. I think this is a good method to use if you are only growing a few beans, because it keeps them upright and stops them becoming a tangled mess that bees can't get into. Obviously if you had loads of bean plants this method might be too laborious.

Well, the quantity of beans this year may be somewhat disappointing, but there's no faulting the quality. This is a batch we ate a few days ago - BBs mixed with peas. The beans here are "Robin Hood" ones, which are small, but very tender and a glorious bright green colour.


  1. All very interesting.. I dont know what im getting from the garden for or unpredictable weather is causing issues it seems that the only thing growing good are the tomatoes if I can keep the bugs off them.. Ugh. Never had such problems before. And my new chard is already turning brown on the leaves I cant believe it. Good lipick with love Janice ps thanks for sharing

  2. I'll be keeping an eye out for your spacing experiment - I've spaced my beans more closely than you at 6" apart (15cm). My shorter variety has a load of pods on it right now and I'll have to give the plants a look in the morning to see if there is a difference in the number of pods that have set in the middle of the bed vs the perimeter.

  3. The other day I noticed my spring sown broad beans (Eleanora express) were similar to this as well - lots of pods at the bottom but not many higher up. I was wondering if the flowers higher up might still produce a few pods even though there's not much left of the flowers, but I shall have a closer look - your theory about the weather sounds about right. Lots of bees on the allotment now though, they're enjoying all the blackberry flowers.

  4. Checked our beans and they are the same.


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