How to grow French beans
Originally from South America, French beans are a great choice for the kitchen garden. If you pick the pods when they're young and tender, you won't have the chore of slicing and stringing usually associated with runner beans.
There are two types of French beans, dwarf varieties (the most common) and climbers. The compact bushes of dwarf varieties grow 30cm-45cm high. Climbers can reach 2m.
Dwarf beans tend to crop over a relatively short period, so gardeners normally make successive sowings. Mature climbers produce pods all summer.
Follow these steps for growing your own French beans and enjoy the fruits (or vegetables) of your labour!
Choosing your site
Choose a well-drained, sunny spot. Make sure it's sheltered, though: French beans can be vulnerable to chilly winds. If you've opted for a climbing variety, bear in mind that the plants will need supporting. There'll be more on support strategies in a later lesson. Tall climbers will cast a shadow over whatever's planted next to them, so site your bean plants carefully.
French beans can grow in most soils, providing they aren't too heavy or too acidic. Nevertheless, a rich soil incorporating plenty of well-rotted compost and organic material is important if you want to get the best out of this crop. The plot should be well dug, to at least a spade and a half's depth, because French beans have deep roots that need plenty of elbow room downstairs. Ideally, the soil should be prepared at least a month in advance but, if you get out there now and prepare a patch, you should be able to sow your French beans in a couple of weeks' time (May).
"Hunter" is a classic variety of climbing French bean. Treat it right and it'll yield masses of long, stringless pods all summer. If you're going for a dwarf French bean, try "Annabel". This stringless variety is also well-suited to growing in pots. "The Prince" is another popular dwarf variety, which produces flat pods.
Pic: GAP Photos/Rice/Buckland
Sowing French beans
French beans are susceptible to cold, so shouldn't be planted outside if there is any danger of frost. By May, though, the soil should be warm enough to give your seedlings a good start. Use a rake to create a fine "tilth" – a crumbly surface soil that's ready for sowing. Peg out a length of garden twine as a guide and create a 5cm-deep drill, or sowing channel. If you're growing a dwarf variety, sow the seeds every 7.5cm. Space your rows 45cms apart. French beans have a high germination rate but, just in case one or two don't come up, sow a few spares at the end of the row.
Climbing French beans are sown at the same depth as dwarf beans but the seeds should be spaced around 10cm apart. Climbers will need 60cm between rows. Sow an even number of rows. Traditionally, some gardeners soak beans seeds before sowing. Avoid this tactic: it can lead to a bacterial condition known as Halo Blight. Cover, firm and label your row. Don't forget to water your new plantings if conditions are dry.
One attractive way to support climbing French beans is to train them up a tepee of garden canes. You'll need to make your tepee first, so that you'll know where to plant the seeds. Take four or five 2.4m canes, lash them together at the top and push them into the ground in a circle, 30cm apart. Sow two seeds 5cm deep at the base of each cane. Things can get rather crowded at the top of the tepee and pods in this apex area are more difficult to harvest. Growing beans in rows will make life easier. But the tepee option is good when space is limited and the construction certainly has visual impact.
Pic: GAP Photos/Sharon Pearson
Nurturing French bean seedlings
Under normal conditions, French bean seedlings emerge from the ground between 10 and 14 days after sowing. Fill any gaps with the end-of-row spares, once the seedlings are big enough to handle. If you're growing climbers using the tepee method, remove the less robust seedling from the base of each cane. Keep down weeds by regular hoeing. Water the seedlings regularly until they're established. Once they are sturdy, don't water them unless the weather is dry. Start watering them again when the flowers appear. Too much water when French beans are young encourages leaf-growth at the expense of flowers and pods.
If you're growing climbers in rows, it's time to sort out some support. Push 2.4m canes into the ground every 15cms. Gather them in pairs from adjacent rows and secure them at the top with horizontal canes. (Now you know why you planted an even number of rows!) You should end up with cane "tunnels". String garden twine along the sides of the "tunnels" for extra support. Theoretically, dwarf varieties don't need support but, if you leave them entirely to their own devices, they may end up dragging their pods in the dirt. So, an informal system of light support using twiggy sticks can be helpful.
When dwarf French bean seedlings turn into young plants, "earth up" the lower stalks to give them more support. Earthing up simply means gently heaping soil around the base of the plant. It's a good idea to mulch dwarf and climbing varieties with organic material. As well as retaining moisture and keeping down weeds, the mulch will add some extra nutrients to the crop. If you like, you can add a layer of clean straw at the base of the plants for lower pods to rest on. Slugs can threaten seedlings and young plants. Protect seedlings with bottomless plastic water bottles. Surround older plants with grit or serrated rings cut from larger plastic bottles.
Pic: GAP Photos/Lynne Brotchie
Looking after French beans
As your French bean seedlings mature into young plants, flowers will develop. This is the point at which to start watering on a regular basis, rather than only when the weather is dry. This will encourage more flowers (and hence more pods) to form. Water carefully at the roots of the plants. Try not to splash the foliage. If you're growing climbers check that they're being supported adequately. Add extra horizontal lengths of twine if necessary.
Many gardeners recommend the use of liquid tomato feed to encourage French beans to produce more pods. Try fortnightly applications. Once the plants have reached the top of their supports, pinch out any growing tips. You want them to concentrate on producing pods, not growing beyond their supports. This is also a good time to think about sowing a fresh crop if you're growing dwarf varieties. Dwarf French beans tend to produce all their pods at once, so re-sowing at monthly intervals will ensure a regular supply all summer. Climbers naturally go on producing pods until the beginning of autumn.
French beans are a favourite among home vegetable growers. The trouble is, they're popular with aphids, too. Green or black aphids can form colonies on growing shoots. Once established, they can weaken and distort growth. If you don't want to use chemical insecticides (after all, the whole point of home-grown veggies is their natural qualities), rub off early colonies as soon as you spot them. Or you can try blasting them off with a spray of water. Keeping weeds down will make the area less attractive to aphids. Another approach is to encourage predators, such as ladybirds, lacewings and hoverflies. The larvae of these creatures love a good feast of aphids! Growing asters, chrysanthemums, marigolds and sedums will attract friendly pest predators.
Pic: GAP Photos/Claire Davies
Harvesting French beans
Quench their thirst
French beans are ready for harvesting between 8 and 12 weeks after sowing. Keeping the crop well-watered at this time – and on into late summer – is vital. French beans suffer if they're allowed to become too thirsty. If you're growing a dwarf variety, don't forget that it's still not too late to sow a few more seeds, to ensure the harvest continues into early autumn.
There are two vital rules about harvesting French beans: pick young and pick often. Young French bean pods are far tastier than mature pods, which are stringy and dull in flavour. The pods you pick should be smooth in appearance and ought to snap easily when you bend them. If you can see bean-shapes bulging along the pods, they are past their best. The most effective way to encourage more young pods to form is to get out there and pick frequently. This is especially important if you're growing climbing varieties. Frequent picking accelerates the plant's natural tendency to produce pods over a long period. Don't pull too hard on the plant when you're harvesting. You may find it easier to use a pair of scissors.
Apart from slugs and aphids (see Lessons 3 and 4), the most likely problem you'll encounter is halo blight. This bacterial condition emerges after cold, wet periods and produces brown spots surrounded by yellow "halos" on the plant's leaves. The spots become water-soaked and go on to infect the pods, too. Older gardening books recommend spraying infected plants with fungicide but many of today's experts disagree. The sprays are often ineffective and may even encourage the bacteria to become resistant. A safer – not to say more organic – course of action is to cut your losses and destroy infected plants immediately. Prevention is better than cure. Always use top-quality seeds, practise good garden hygiene and avoid overcrowding.
Pic: GAP Photos/Rob Whitworth
Harvesting & drying late French beans
Your earlier sowings should be producing plenty of pods by now. Give the crop lots of water and don't forget that the more pods you pick, the more pods the plants will produce. This is as true of climbers as it is of dwarf varieties. If you're faced with a glut of beans and you've already given away loads to your friends, you can freeze a few batches. Top and tail them in the normal way and blanch in boiling water for three minutes before cooling and freezing.
As summer turns into autumn, cooler weather will present some challenges to late-cropping climbers. Protect them by mulching with straw. Dwarf varieties can also be harvested late, provided that they are protected. Sow in late July for an October harvest. In mid-September, protect the young plants with cloches. Cloches are transparent frames that keep crops warm by making the most of weak sunlight and the plants' own heat. Garden centres sell basic cloches or you can buy collapsible poly-tunnels that will do the job just as well.
Did you know that the beans inside French bean pods become haricot beans when they are dried? If you fancy brightening up the odd winter day with a warming casserole of home-grown haricot beans, try drying the last of your crop. Stop picking and wait until all flowering has ceased and the pods have turned golden-brown. Leave the plants alone as long as the weather stays dry. When wet weather threatens, cut the plants at ground level and hang them somewhere dry and airy until the pods are truly brittle and beginning to split. Then shell the beans and dry them out further on a sheet of paper for a few more days. Store them in an airtight container. Don't forget to compost the old plants so that they will enrich your soil for next year's crop of home-grown veggies.
Pic: GAP Photos/Nicola Browne