Once a staple late summer crop in the UK, the runner bean had fallen out of favour until recently and is now roaring back into popularity as gardeners, cooks and consumers realize how delicious this bean is when picked young rather than left to get old, chewy and stringy.
Like all peas and beans, runner beans are members of the legume family and therefore fix nitrogen for the benefit of themselves, the soil and other crops around them. This does huge favours for both gardener and garden.
They are very easy to grow in both garden soil and large containers. Headlines to flag up are that slugs will be very keen on the young plants in a wet year while in a dry summer they may well need to be watered. They carry a lot of both foliage and crop for a plant with a small root system and if things get very dry when they are at their peak in late July and August they will suffer and require regular watering.
If you are sowing them in the garden the soil need only be broken down to a reasonably fine tilth i.e. half a cornflake size. When sowing you push the bean 3-4cm into the earth so there is no need for a finely raked seed bed. Do add compost or well rotted manure though, this they will appreciate. Half a barrow or a filled bucket per square metre.
I sow my seed directly in the garden having first erected a teepee of 2.5m high canes or bean poles. This is done by driving 8 or 9 poles in 30cm apart in a circle, leaning them in so that they can be tied in a bundle at the top with string. Runner beans are able climbers with a leading shoot that twines itself easily around a pole.
In a wet year it is sensible to sow beans indoors and plant them out when the plants are robust and showing at least two ‘true’ leaves. The ones that are heart or trowel-shaped. This may give them a head start on the snails if it is rainy and cold.
Sow the seed direct into 9cm square pots at a depth of 2-3cm. Water well and keep in the sun. I leave sowing until the beginning of May because runner beans are very frost tender and do not appreciate the cold.
Be sure to harden plants off properly before planting out. Hardening off is the process of gradual acclimatization that plants must go through at planting out time if they are to adapt to their new surroundings without too much shock.
It is done by bringing them out of the greenhouse or from the warm windowsill into the garden for a day, bringing them in at night and so forth for a couple of days before you finally leave them out at night for a couple of nights before planting.
Plant a single bean plant directly at the base of a cane or pole and give a good water.
A wide mouthed container like an old holey bucket is good so you can fo at least three plants in at 20cm spacings. Again you will need canes for the plants to cling to. Use garden compost and do remember that containers with big plants dry out very quickly so water them every day and every third day give the pot a real good soaking, once the plants have climbed halfway up the poles.
Runners don’t take much looking after. Keep the weeds away from the base and check the solidity of the teepee periodically when rain and or strong winds are expected. Heavy rain on a full teepee will put pressure on it.
Watering, especially in containers, is very important as already discussed.
This must begin once the beans are the length of your middle finger. Whatever you do don’t let the beans get more 15-20cm long. They will have lost flavor by that stage and become stringy and sharp.
Pests and diseases
Runners are pretty trouble free apart from the aforementioned slugs in a wet year. Keep checking low growing beans when ready to harvest because they could be troubled by slugs and snails as well.
Crop removal and seed saving
Runners are an easy crop from which to save seed. This entails leaving a dozen or so big pods to grow as big as possible, even into the depths of November if you can keep the crop in the ground without needing to remove it. The green pod will change to brown and ultimately to a thin wrinkled parchment. Don’t worry about the weather, rain won’t affect anything. Leave them on the plant until they are completely brown. That’s the time to harvest and bring inside to a warm dry place where the pods can finish drying.
Runner beans need to be eaten quickly, certainly within 24 hours once picked. The most important tip is to use the tool that removes the string from either side of the bean. It is invaluable and should be used on any size of runner bean. It makes the eating experience so much more pleasurable. As does the addition of salt to the water used to cook them. They taste much better if cooked in salted water rather than steamed. The salt brings out the flavor. Once almost cooked chop a clove of garlic finely and fry lightly ion some butter before adding the beans and tossing them around for a minute or two.
In all honesty there is little to choose between varieties of runner bean. Scarlet Emperor has been around forever and has stood the test of time. Painted Lady has a pretty red and white flower.