French Beans

French Beans are also known by a variety of names such as kidney beans, flageolets and haricot beans - these names refer to the beans when left to mature fully.


Latin Name
Phaseolus coccineus

Perennial, but grown in UK as half-hardy annual.

Site and Soil
Full sun, sheltered from wind. Well-dug water retaining soil.

Plant to Harvest Time
12 weeks

How Many?
3kg (6.5lb) per metre (yard)

The taste is always better than those bought in the shops, because you can grow varieties not suitable for commercial production. You also choose when to harvest them - just before they are needed for cooking.

In normal circumstances French Beans can be harvested starting July up to early October. Given cloche protection, they will be ready for harvest in June.

Where To Grow French Beans
French beans prefer a sunny, sheltered site because it gives protection from cold winds which helps at the seedling stage and later on during the pollination phase. If the climbing type is to be grown (as opposed to the dwarf variety), remember that they will need support to 1.8m (6foot) and that they will cast a shadow over any nearby low-growing plants.

Soil Preparation
French Beans prefer a rich soil which has plenty of organic material in it. They have a deep root system, so digging should be to a spade and a half's depth, incorporating compost or other organic material during the process. If possible, prepare the soil a month or so in advance of sowing the seeds, March is a good time.

When To Sow French Beans
French Beans are very frost-tender at the sowing and seedling stage and if unprotected, will in almost all cases damaged by any degree of frost. Where the seedlings have appeared above the soil surface and a late unexpected frost strikes, it is best to remove them and plant more seeds in their place.

The best time to plant French Beans outside is around the time of the last frost.  If poly tunnel or cloche protection can be provided (or if planting in pots indoors), the sowing date can be 4 weeks before the last frost date in your area.

How To Sow French Beans

Sowing Directly Outside
French Beans are sub-tropical in origin, and for this reason need a minimum soil temperature of 16°C (60°F). If unprotected, French Beans are in all cases damaged by even one degree of frost. Where the seedlings have appeared above the soil surface and a late unexpected frost strikes, it is best to remove them and sow more seeds in their place.

Picture of French Bean variety Purple Teepee
French Bean variety Purple Teepee
(available from Dobbies)

Using a trowel, dig out drills 5cm (2in) deep and 30cm (1ft) apart - where more than two rows are being planted, allow sufficient space between every second row to allow you cultivate and harvest them. 1m (3ft) should be enough. 

French Beans have a germination rate of approximately 75% and for this reason should be sown thinly, one seed every 15cm (6in). Thin out to a final spacing of one seedling every 30cm (1ft) about 3 weeks after sowing. To be doubly sure, sow several seeds at the end of the row for filling in any spaces where the seed has failed to come up in the row. After sowing, water the bed well if conditions are at all dry.

Do not soak the beans prior to sowing in attempt to encourage germination. Soaking will encourage Halo Blight. Examine the beans as you sow them, and reject any which are wrinkled, disfigured or have yellow spots on them. 

Sowing With Frost Protection
Cloches or poly-tunnels will protect them if a late frost is predicted, as will plastic bottles with the bottom cut off placed over the seedlings. Sowing under cloches outside can occur in April.

The other alternative is to sow the seeds in peat pots (during April) and initially grow them on the windowsill until all danger of frost has passed and then plant them, peat pots and all, directly into the ground. Remember to soak the peat pots in water prior to planting so that they will quickly break down in the soil.


Supporting French Beans
picture - supporting French Beans

Dwarf French Beans may not require support in good conditions. However, the weight of the pods does tend to drag them to the ground, attracting slugs and other pests. It is best to tie them into a short bamboo pole or let them scramble through twigs inserted into the ground next to them. This will also give some protection to the plants if the weather conditions turn windy.

The climbing varieties of French Beans grow to about 1.8m (6 foot) high and they definitely need support. The idea is to provide a structure which their tendrils can grow round and pull the plant up. 

Picture of wigwam for beansThe most attractive form of support is a wigwam - four or five bamboo canes tied together at the top will be sufficient. The growth at the top will be a bit crowded, but this structure will still produce a good crop of beans.

It is a good idea to twist some gardening twine round the bamboo canes, this will give the growing plants more to grab hold of. 

Where space is really short, this type of structure can be used for container growing French Beans. In this case, insert one cane centrally in the container, tie six or so lengths of garden twine to the top of the cane and secure the other ends of the twine to the edge of the container. Plant three or four seeds, which will then grow up the twine. The plants will need their tips pinching out when they reach the top of the twine.

Other methods are to erect a criss-cross of canes, each pair tied together at the top, or simply a line of canes connected together with mesh netting. Finally, don't forget that runner beans can be be grown up an existing fence which has been covered with mesh netting.

Caring For Your French Beans
The requirements of runner beans are simple, water and weeding, possibly some feeding. All three can be accomplished by a mulch of organic material spread round the plants. This will help retain moisture, keep the weeds down and gently feed the plants. If the soil has been prepared as described previously, the only other attention is hand watering in very dry conditions, especially as the flower buds begin to develop. A special treat for French Beans is watering with Tomato Plant food every couple of weeks if possible. Finally, pinch out the growing tips when the plants reach the top of the supports.

Harvesting French Beans
French Beans will be ready for harvesting in mid July, and this should continue into October. Pick the beans when they are young, leaving them too long will result in a crop of stringy beans. Length of the beans does not let you know if they are ready, rely on the texture of the beans. They are past their best when the skin is coarse textured and the beans inside begin to show through like small marbles.

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