RHS Growing Guides
How to grow French beans
Our detailed growing guide will help you with each step in successfully growing French Beans.
Getting Started
Straightforward to grow and ideal for beginners, French beans produce good harvests in a relatively small space and are highly decorative too, with pods in a choice of colours. There are compact fast-cropping dwarf varieties (up to 45cm/18in tall), ideal in containers and windy sites, and larger climbing varieties that crop over a longer period. Both are easy to grow from seed sown outdoors in late spring or early summer, either in the ground or in containers. Or for a head start, sow indoors then plant out in late spring, after the last frost.
Month by Month
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Choosing
There are two types of French bean – climbing and dwarf. Dwarf beans are perfect for small spaces, growing well in containers and in the ground. Climbing beans need tall supports and do best in the ground, but can also be grown in large containers. As they grow vertically, climbers produce a large crop in a relatively small area of ground.
Dwarf beans are quick to grow, but only crop for a few weeks, so you need to make repeat sowings for a summer-long supply. Climbing beans take longer to reach cropping stage, but will then produce beans over a longer period, from mid-summer to early autumn if picked regularly.
French beans bush variety
What and where to buy
A huge range of varieties, of both dwarf and climbing, are readily available as seed in garden centres and from online retailers.
If you don’t have the time or space to grow from seed, young plants can also be bought from garden centres and online suppliers in spring and early summer, ready for planting outside. However, the choice of varieties may be fairly limited.
Recommended Varieties
French beans — climbing
A climbing variety with exeptional flavour. Produces heavy crops of stringless beans over a long period. Has attractive...
A climbing bean with straight, flat, mid-green pods and totally stringless.
An attractive golden-yellow climbing bean which produces a heavy crop over a long season.
Preparing the Ground
Choose a warm, sunny growing site. Weed the area thoroughly, then add plenty of well-rotted manure or garden compost – at least two bucketfuls per square metre/yard – to improve moisture retention in the soil. This should ideally be done a few weeks ahead of sowing or planting out, to allow time for the ground to settle, or even the previous autumn if you’ve planned out your growing site early enough.
Sowing
Putting up supports
The traditional method is to grow them along a double row of bamboo canes (2.5m/8ft tall), with at least 45cm (18in) between the two rows. Space the bamboo canes 15cm (6in) apart within each row and slope them inwards, then tie near the top to a horizontal cane, to form a sturdy A-frame.
Alternatively, create an X-frame by sloping the canes at a sharper angle so they cross in the middle. Tie them at the centre, and add a horizontal cane to link them all together and increase stability. An X-frame takes up more space, but picking is easier as the beans are within reach and cropping is usually better.
If you don’t have room for a double row of canes, you can make wigwams. Again, use 2.5m (8ft) canes, four or five per wigwam, spacing them 15cm (6in) apart at the base. Tie the tops of the canes together. Wigwams make an attractive feature in a border or veg plot and also work well when growing in containers.
With dwarf beans, you can insert short twiggy sticks between the plants to keep them upright and lift the pods off the soil.
Sowing indoors
For an early crop, sow indoors in late April to early May. Use small pots or trays of deep modules, sowing one bean in each, 5cm (2in) deep. Place in a propagator or on a warm, sunny windowsill to germinate. They will grow fast in warm, bright conditions and need watering regularly.
In late May or early June, harden off the young plants to acclimatise them to outdoor conditions. Then plant into their final site, after all risk of frost has passed – see Planting out, below.
Sowing outdoors in the ground
Before sowing, prepare your ground carefully and put supports in place for climbing varieties – see above.
French beans can be sown outdoors once all risk of frost has passed and the soil is warming up – usually in late May or early June, depending on your local climate. Warming the soil with fleece or cloches for a few weeks before sowing can aid germination, and if left in place they’ll also give the seedlings extra protection.
Sow the seeds individually, 5cm (2in) deep and 15cm (6in) apart. With climbing beans, sow one or two at the base of each bamboo cane, then thin out the seedlings if necessary to leave the strongest one.
Dwarf beans are best sown in blocks or double rows, so they support each other. Sow a few extra at the end of the rows to fill any gaps if some seeds don’t germinate. You can also sow these through weed-suppressing membrane to reduce the need for weeding and prevent the pods being damaged by contact with the soil.
To provide harvests over a longer period, make several sowings of dwarf beans from late spring right through to late summer.
Sowing outdoors in containers
You can sow seeds outdoors in spring into pots of multi-purpose compost – either in small pots for transplanting into the ground later, or large containers as their final growing site.
Sow one bean per small pot, 5cm (2in) deep, then place in a cold frame or a warm, sheltered position, protected with fleece. Once the plants reach 8cm (3in) tall and all risk of frost has passed, plant out into their final positions (see Planting outside, below).
Both dwarf and climbing beans can be grown in large containers and make attractive additions to patios and small gardens. They need a warm, sheltered, sunny position. For dwarf beans the container should be 30–45cm (12–18in) wide, and for climbing beans 75cm (30in) wide, 45cm (18in) deep and heavy enough to keep it from toppling over once the climbing beans are at the top of their supports.
For climbing beans, insert a wigwam of 2.5m (8ft) canes (see Putting up supports, above) into the container before sowing. Dwarf beans don’t usually need support and look great cascading over the sides of a pot or even in a hanging basket.
Then simply sow the seeds into the container of potting compost, 5cm (2in) deep and 15cm (6in) apart. With climbing beans, you can sow one or two seeds at the base of each cane, then thin out the seedlings if necessary to leave the strongest one.
Planting
Wait until after the last frost before planting indoor-raised or bought young plants outside. Harden off to acclimatise them to outdoor conditions for a couple of weeks, either by putting them in a coldframe or placing them in a warm, sheltered spot, covered with fleece.
Make sure your planting site is ready – see Preparing the ground and Putting up supports above.
If planting in a container, choose multi-purpose or loam-based compost. Containers should be at least 30–45cm (12–18in) wide for dwarf beans, and 75cm (30in) wide and 45cm (18in) deep for climbing beans.
Water the plants well, both before and after planting, and space them 15cm (6in) apart.
With climbing beans, plant one at the base of each bamboo cane, then loosely tie the shoots to the cane to get them started.
Plant Care
Watering
French bean irrigation system
Watering french beans
Mulching
Place a mulch of well-rotted manure or mushroom compost around plants in July to help hold moisture in the soil.
Weeding
Keep the growing site weed-free. Consider planting through slits in weed-suppressing membrane – this reduces the need for weeding and prevents the pods of dwarf beans being damaged by contact with the soil.
Propagating
French bean flowers are self-pollinating, so plants grown from saved seeds are likely to be true to type. At the end of the cropping season, leave a few pods to fully mature, then pick once dried. Remove the seeds from the pods, then store in a labelled paper bag somewhere cool and dry over winter, to sow the following spring.
Pruning and Training
Once climbing beans reach the top of their support, cut off any extra growth. This should encourage side-shoots lower down, keep the crop within reach and help to stop plants becoming top-heavy. Tie in any shoots that come loose from the canes, especially in windy sites.
Harvesting
Problems
French beans are easy to grow and generally trouble-free, but they are tender, so must be kept indoors until after the last frost. If an unexpected cold snap is forecast, cover your plants overnight with cloche or fleece.
Seedlings and young plants are vulnerable to slugs and snails. Keep watch, too, for black aphids on shoot tips and under leaves – squash them or wash them off with a jet from the hose before they get established.
French beans also need plenty of moisture, so water them regularly once they start flowering, especially during dry spells.
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