Is it ok to put Runner Bean and Dahlia tops on the compost heap?

[JohnParticipant]

Hi Charles

One of my neighbours, a champion pumpkin grower, took his runner bean tops with some pods attached, to the tip today in spite of him being a keen composter. I asked him why and he said he didn’t want new plants popping up everywhere next year and he was concerned about disease being carried over.

Another neighbour is a dahlia expert (a judge at Wisley no less!), yet he dries and burns his dahlia tops in case of disease being passed on in compost to next year’s plants.

Both are very experienced gardeners of the old school. Are they correct?

Presumably with applying compost to the surface, rather than digging it in, would not cause a rush of runner bean seedlings but , in any case, my guess is that the seeds would rot in a heap.

[charlesModerator]

John I am amazed by this and find it the sort of thing that can put people off gardening. I have just had runner beans for the third year running, in the same beds, giving the heaviest and healthiest crop so far. Runner bean plants do not exactly “pop up” anyway, its bizarre.

I think that burning organic matter is a terrible waste and also it releases carbon to the atmosphere instead of where it is needed.

Its more effective to build soil health so that diseases cannot damage our plants, even when they are present, which they usually are, in small amounts. Its more about resistance than avoidance.

And yes no dig helps build the health (disease-resistance) of both soil and plants.

[JohnParticipant]

Hi Charles

My thoughts exactly but there are so many entrenched views on the allotments. None of my immediate neighbours have a compost heap and I find it such a waste. I have offered to receive broad bean and runner bean haulms but even then there is some resistance.

I am not keen on receiving roots from other plots in case of soil borne diseases. I have onion white rot and wouldn’t want to pass it on. Would you be wary of plant roots with, inevitably, some soil attached?

[Plot 33Participant]

I often see vegetative material (recently rhubarb leaves and purple sprouting broccoli plants, masses of apples & forked carrots!) dumped on our waste collection point. I wonder why my fellow plot holders aren’t making use of this valuable composting material, most of us have built compost heaps/ bins on our plots.

The other thing that bugs me is that often when taking a new weedy plot, they ‘scrape off’ the top two/ three inches of soil (with weeds/ couch grass) and deposit it on the dump. When I first got my plot (a weed covered bramble patch the size of a tennis court!) I strimmed it, covered areas with cardboard, weed suppressant fabric &anything else we could get our hands on. Then we dug it over. I wouldn’t have dreamed of removing the top level of soil, but I see others do it. I think the old guard on my site must advise newbies to do this. While they are removing soil & humus, I am adding to it!

John, I would have thought that by turning compost heaps from time to time, the runner beans wouldn’t cause a problem in the compost? The heat should deal with it.

[peatParticipant]

Runner beans are perennials so wouldn’t be a problem staying in the same bed. You could cut them back to ground level and protect from frost and they will grow again the following year. A lot of rubbish is talked about compost making and as once been a compost advisor I find it annoying. Most diseased material will break down in a compost heap as it becomes food for other bacteria, Heat is only needed to break down seeds.

[RhysParticipant]

I have to say I’ve not seen any problems with composts or ‘errant bean seeds’ through composting all the bean plants the past three years. Biggest issue around here for beans are droughts and warm nights. I’ve just been building an over-wintering pile with:
1. Cardboard (four separate layers up the heap).
2. Comfrey leaves, carrot foliage, Sarpo Mira potato foliage and runner bean plants (again four levels).
3. Rotted horse manure as well as fresher horse manure with plenty of straw in it.

It’s already rotted down significantly in terms of volume reduction and I’m getting ready to cover it for the winter with polythene now we’ve had another good batch of rain yesterday.

I can also say that the health of plants this year in the second season of no-dig has been broadly better than previously, especially this years spring cabbages planted out three weeks ago – they have taken beautifully, grown significantly and look much better than last years (which produced a healthy crop anyway).

I’m sure I’ve still got a lot to learn about producing optimal composts when you don’t have enough material often to build a cubic metre pile in a oner. But I’ve certainly not yet found any issues about using garden waste in the compost bins.

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