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The Permacultivator - Journal of Cool Climate Permaculture
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Getting The Best From Your Beans

David Murray presents some backyard research on one of his favourite topics.

"Climbing beans give heavier yields, longer crops, easier harvesting and more efficient use of space in the garden than bush beans." Meg Herd (1994) The Food Garden (Bay Books), page 57.
This sweeping presumption is widespread among gardening writers, but how true is it? Certainly climbing beans make good use of available space, and they are much easier on the neck and the knees while you are looking for pests, or picking the beans. However, in favour of dwarf kinds is the fact that they are usually much faster between planting and flowering. Stella Bianca is a good example, taking only 32 days between planting and the first flowers in good summer conditions, with edible pods following just 2 weeks later. Under identical conditions, the climbers generally take 2 to 3 months to begin flowering. This is a very good reason to plant both kinds, in appropriate locations.
Dwarf beans are much closer in contact with companion plants such as zonal pelagonium and basil, plants that can deter white fly. This influence wanes as beans get taller. Another good reason to favour dwarf kinds at the beginning and end of the bean season is their better tolerance of cool conditions. Beans like Stanley's Surprise can be started earlier (eg September) and beans like Brown Beauty can be sown late, producing edible pods 2 months after planting in the first half of March. It is easily possible to grow dwarf beans twice in the same location in the one season.
This evens out any real or imagined yield advantage of the climbers, which can be grown only once.
The following table provides some sample data for bean plants grown mainly for seed yield. This is not quite the same as growing beans primarily for eating as immature pods, although bean pods were picked for eating from these plants as well as being kept for maturation. So long as flowering continues, the removal of pods for eating should not affect the final seed yield significantly.

The Tables below show Production Parameters for Bean Growing in 30cm-pots in Wollongong New South Wales (2002-3 or 2003-4 Summer Seasons).

Dwarf Kinds
dwarf

Climbers
climb

Climbing Lima Beans
lima

Some interesting features emerge. The outright winner is Purple King sown in the garden, but note that the number of seeds per plant per pot can reach 50 or more for both dwarf plants and climbers. For a given variety, the number of seeds per plant is affected by the number of plants per pot; against the likelihood that one or two might be lost as casualties before maturity. But three or four plants surviving will result in a suboptimal yield per plant, especially so for four climbers. The yield per plant is higher for one or two plants per pot. But putting only one or two seeds in such pots is actually a much riskier strategy, and could easily result in no yield at all.

In summary,
* Choose varieties that suit your local environment, noting that the results I get in Wollongong will not necessarily be the same where you live;
* Plant some varieties as early as possible (eg September) and as late as possible (eg first half of March);
* Plant 3 plants per 30cm pot, which allows for attrition, without seriously denting yield per plant if all three happen to survive;
* Keep planting and replace failed seeds or plants immediately;
* Keep picking, as this stimulates continued production;
* Deal smartly with the usual pests: snails, slugs, white fly, 2-spotted mite, grasshoppers, birds;
* Watch out for unusual pests, such as grass blue butterfly;
* Keep removing the older leaves as they senesce, because you remove many pests with the leaves (plunge them into the middle of the compost heap);
* Save the seeds and pass them on!

J 46 Summer 2004 - Autumn 2005