French beans produce wonderful ornate flowers that go on to form edible bean pods. They are worth growing for their aesthetics alone. Even better is that they require little space in the garden or allotment, yet contribute a sizeable harvest. If the harvest is too big to eat all at once, any leftover beans can be frozen to enjoy through the winter (wash, top and tail, blanch, and freeze).
French beans are a space saving crop because they grow upwards. Climbing varieties can reach 3 metres high when supported on a wigwam or trellis, whilst the many drawf varieties grow to about 50 centimetres – these are ideal for growing in pots and do not need support. Aside from their growth habit, climbing beans typically have a longer harvesting season over several months, compared to dwarf varieties that produce over several weeks. For this reason, you may like to grow different varieties of dwarf varieties, or sow them in two waves, to extend the harvest period.
French beans are similar to runner beans in that they are frost sensitive. Early sowings need protection, and only planted out after all risk of frost has passed. The big advantage of French beans over runner beans is that French beans are stringless. The pods should be picked young when they are about 10 centimetres in length after which the skin starts to harden. During the flowering and harvesting season, ensure the plants are well watered as this will increase harvest size.
You may decide to allow your French bean pods to mature to harvest the beans themselves. The immature beans are sometimes called flageolets, whilst the mature beans are known as haricots. It is important to remember that all beans contain toxins in both the beans and the pods. The beans are edible, but they must be cooked by boiling vigorously for at least 10 minutes to remove toxins that can cause food poisoning (like red kidney beans), and then simmer longer to soften. Dried beans may have more toxins than fresh beans, and will need additional soaking for 12-24 hours before cooking.
Young French bean pods have less toxins than mature beans, but they should always be cooked and not eaten raw. This is an introduction to cooking French beans, the amount of toxins will differ per variety so you may want to check this before growing (and cooking), or follow a recipe from a trusted source.