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Home & garden.

Updated: 6 Dec 2021

How to grow French beans

Chose between climbing French beans or dwarf ones for delicious summer crops. Discover our best french bean varieties and tips for how to grow them.
Ceri Thomas
French beans

 French beans are easy to grow from seed. Plant them outside once the danger of frost has passed in late spring.

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How to grow French beans: month by month



Best French bean varieties

Which? members can log in now to see the full results and which are our Best Buy varieties. If you’re not a member, join Which? to get instant access.

Best Buy dwarf French beans
What it looks likeVariety nameYield per plant
Producing almost 6kg of fine, round beans from a 2.5m double row, this was the best-performing green bean. We started picking in mid-July, and the bulk of the crop came in mid to late August, with little drop-off in overall quality until the end of the trial in late September. Being an open-pollinated variety, it will breed true, so you can save seeds for use the following year.
What it looks likeVariety nameYield per plant
A yellow-podded variety, RHS-AGM holder and previous Best Buy, this gave us the largest yield in our trial. The pale golden pods developed from white flowers, with the first beans ready to pick around a week later than others. The bulk of the yield came during August, including a bumper crop of 2.2kg from just one picking at the end of the month. By the end of September, the quality dropped slightly, with some beans becoming rather curly.
What it looks likeVariety nameYield per plant

How we test French beans

We grew French beans and recorded when the first flowers appeared on each of our varieties. And once they started to produce beans, we picked weekly, weighing the beans and assessing them for quality. We also rated how easy the beans were to pick.

When to sow

Avoiding gluts of beans

Beans produce plentiful crops so to avoid being overwhelmed, the trick is to grow just the right amount of plants for your needs. In the Which? Gardening magazine trial, most varieties produced at least 0.5kg per plant, and our Best Buy runner-bean varieties produced up to 1kg per plant in a season. So a single wigwam of a dozen plants would be plenty for a small household.

How do climbing French beans and runner beans compare?

While climbing beans are slightly sweeter and juicier than runner beans, the real difference is that they’re not as tough or stringy. Most of the varieties we tried gave stringless, tender beans, even if they were left to grow quite big on the plant. Our Best Buys will provide a large yield, too. French/runner bean crosses don’t need pollination so are more reliable croppers than runner beans.


French beans need warm soil and are very sensitive to frost. Start seeds in the greenhouse in late April into May, using module trays or small pots filled with Best Buy compost for sowing seeds.


Wait until all risk of frost has passed (late May to June) to sow direct into the ground. Sow about 1.5cm deep in double rows 15cm apart. Make successional sowings to prolong the harvest.

Caring for your plants

Creating a support for climbing beans

Use bamboo canes, at least 2.4m tall, pushed well into the ground. You'll see all kinds of imaginative structures on allotments, but when Which? Gardening trialled bean supports, we found that the best three methods were: wigwam, X-frame, and A-frame.  

A wigwam is quick and easy to put up. It also has a neat, compact shape that takes up little space. 

An X-frame is created with pairs of bamboo canes inserted at 45 degrees to the ground, crossing halfway up and tied in the middle. These are strengthened by a horizontal pole tied where the canes cross. The beans are easy to pick as they hang on the outer edge of the support. 

An A-frame is very robust, easy to erect and dismantle, and good at suppressing weeds.


Harden off plants started in the greenhouse before planting outside after the last frost (mid-May to early June, depending on where you live), allowing 15cm between plants. If a late frost is forecast after planting, protect the seedlings with a layer of horticultural fleece.

Most dwarf French beans shouldn’t need any support, but in exposed areas or if the plants seem a bit leggy, a few twiggy sticks or canes and string will do the job.


Water well in dry periods; covering the soil with a mulch of spent mushroom compost or garden compost will help to conserve moisture and also keep weeds down.

How and when to harvest

Harvest in: July to October

Pick when beans are 10-15cm long and before they show signs of seed formation. It’s best to snip off beans with scissors or nip them between your finger and thumb; pulling the beans risks unearthing the whole plant if it's a dwarf variety. Don't leave any pods to grow old on climbing beans unless you want to save seeds. Picking regularly will encourage the plants to produce lots of beans.

If you want to save seeds, especially if you’re growing an open-pollinated variety, leave the beans on a couple of plants and allow them to dry until the beans rattle in the pods before collecting them.

Common growing problems

Yellowing plants

Planting too early when temperatures are low will cause bean plants to turn yellow and fail to thrive. The best advice is to resow at the right time and start again.


Blackfly is the most common pest and damages the plants by sucking their sap. Either squash these insects or spray them with an organic insecticide. 

Read more about blackfly. 

Slugs and snails

Slugs and snails can munch their way through young seedlings. Pick off any you find and protect plants with organic slug pellets.   

Read more about slugs and snails.


Prevent birds, particularly pigeons, from pecking plants with a covering of garden netting or fleece.  

Read more about birds.


Alternaria is a fungal infection that causes leaf spots, and thrives in the mild wet weather. Remove any affected leaves.