How to grow Runner and French beans

Beans are some of the most popular, grown and easy to grow vegetables in our garden. There are a few different types each with several varieties but in general they all like the same conditions and have similar requirements. 

How to Grow Runner Beans

Like climbing French beans, runner beans are also tender and require support. They’re one of the tallest vegetables in the garden reaching heights of up to 3m (10ft) and they produce an abundance of long bean pods that can reach 30cm (12in).

They are often more flavoursome than French or broad beans. They are thought of as an easy crop to grow but if soil preparation, watering, support and regular harvesting are not done correctly runner beans won’t thrive.

When is the best time to grow runner beans?

Runner beans can be sown from mid-May to the end of June, sow them 5cm deep and 15cm apart.

The seeds can also be sown indoors at the end of April and transplanted out at the end of May or start of June, once the risk of frost has passed.

How to sow Indoors

  1. Fill pots with moist multipurpose compost, around 7-8cm full.
  2. Sow one seed per pot, 5cm (2in) deep and water the pots well.
  3. Grow in warm conditions, a greenhouse or sunny windowsill is ideal.
  4. Harden off the young plants and plant out when the risk of frost has passed.

How to sow Outdoors

Preparing the soil

It is vital that soil preparation has been undertaken before sowing. In the autumn before sowing, improve the soil with a general fertiliser. A slightly acid soil pH of 6.5 is preferable when growing runner beans. To help reduce soil which is too acidic add lime. Avoiding waterlogged soil as well as ground that has had beans growing the previous season is also recommended.

How to make a bean trench

For best results, runner beans should be planted in rich deep, fertile soil that is exposed to sun throughout the day. The traditional method of preparing soil is to use a bean trench, however, other methods are also good.

  1. Choose a sunny spot and prepare the ground in the autumn prior to planting by digging a bean trench.
  2. Mark out a line and dig out a trench 90cm wide and 60cm deep.
  3. Fork over the bottom of the trench as deep as you can to improve aeration and drainage.
  4. Fill up trench with well-rotted garden compost or manure.
  5. Two weeks before sowing apply a general fertiliser in the bottom of the trench.
  6. Leave the soil to settle for two weeks before planting.

Creating a support for the Beans

Before sowing the seeds, a support should be constructed for your beans to climb up.

There are multiple methods to help support your beans:

  • The traditional method is to use bamboo canes either in a wigwam or in a row, but string, wire or mesh works equally well.
  • They can also be grown over existing arches or against fences and walls. Rows need to be 45cm (18in) apart and canes pushed 30cm (12in) deep at 20cm (8in) interval and tied at the top.
  • Sow seeds 5cm (2in) deep on the inside of each cane. Alternatively, if you’ve sown seeds indoors, plant out at the same spacing, loosely tying in young plants.

How to Care for Runner Beans

When flower buds appear water well especially when the weather is dry. When plants reach the top of the support pinch out growing tip.

When is the best time to harvest runner beans?

Harvest when pods are between 15cm (6in) to 20cm (8in) and while the pods snap easily and the seeds are still pale, from mid-July through to the first frost.

Pick continuously, at least every other day, to retain a good harvest. Whole pods are normally eaten but seeds can be dried and stored. If beans are allowed to go to seed then they will stop producing flowers and beans.

What are the best varieties of runner beans?

  • Firestorm: lauded for its brilliant red flowers and unique ability in runner beans to self-set without the aid of external insect pollination.
  • Stardust: Stardust produces masses of self-fertile white flowers on vigorous plants. They set well no matter what the weather to give you deliciously tender, stringless beans that are full of flavour.

Pest and Diseases of Runner Beans

• Seed Beetle
• Bean Seed Fly
• Black Bean Aphid
• Downy Mildew
• Powdery Mildew
• Foot Rot & Root Rot
• Pea & Bean Weevil
• Flowers Not Set
• Halo Bright
• Chocolate Spot
• No Pods
• Marsh Spot
• Birds
• Botrytis
• Fusarium Wilt
• Anthracnose

How to Grow French Beans

Unlike broad beans, French beans are half hardy and are sown from mid May for this reason. Despite being more tender they are just as easy to grow as broad beans and are a good intermediate crop until runner beans are ready for picking. There are several types including, climbing, dwarf, flat-pod and pencil-pod and are available in green, yellow and purple pods. They are primarily eaten whole when young and tender but the beans can be dried for Haricot beans or eaten fresh as Flageolet.

How to Prepare the soil for sowing French Beans

French beans will grow in any warm, fertile and well-draining soil. They don’t thrive in areas of heavy clay, to prepare the ground dig in well-rotted organic matter, such as garden compost, before planting. Choose a sunny spot and prepare the ground in the autumn prior to planting.

Two weeks before sowing apply a general fertiliser. Climbing varieties benefit from a trench being dug (see runner beans).

Cultivation of French Beans

French beans can be sown outdoors or indoors and then planted out. Growing indoors is the common method for colder areas.

Growing French beans outside

  1. To sow the seeds the soil shouldn’t be wet, or temperatures be lower than 10°c (53°F) as this produces bad germination results.
  2. Seeds should be sown 10cm (4in) apart in drills 5cm deep, leaving 45cm (18in) between rows.
  3. Two outdoor sowings, three weeks apart ensure a long harvest period.

Growing French beans inside

Sowing French beans indoors first is a more reliable growing method. They can be sown in late April to early May, if an earlier harvest is wanted. To grow:

  1. Initiate germination by placing beans on damp kitchen roll and wait for them to swell.
  2. Any that aren’t plump can be discarded.
  3. Sow seeds in cell trays or root trainers, one bean per pot 5cm deep.
  4. Harden off the young plants and plant out when risk of frost has passed, usually around the end of May, early June.
  5. Climbing varieties will need support but it’s beneficial to prop up all plants for ease of harvest and to keep the crop clean.

Growing Dwarf French beans

Dwarf French beans grow to about 45cm (18in) tall. They are best grown in small blocks, where their neighbouring plants can help provide support. The plants should be spaced about 15cm apart.

If there is an unexpected cold snap, after planting, protect the plants using fleece or newspaper until the weather gets warmer.

When the plants have started flowering, water them well during periods of dry weather. Adding a well-rotted manure or compost to the plants, around July, can help preserve some of the moisture in the soil during the warmer months.

When to harvest french beans

The beans should be ready to pick from the end of June when the pods are about 10cm (4in) long, pick the young and tender pods. Regular picking will encourage more growth and produce a bigger crop.

For green beans the pods should be picked before visible signs of the beans appear. For Haricot beans wait until the pods turn a straw colour then hang the plants indoors to dry. When the pods begin to split, collect the beans and dry for a few days before storing them in an airtight jar.

Best Varieties of French Beans:

  • Delinel: Grow the summer-long dwarf French Bean Delinel to give you lots of ultra-fine deep green beans with a unique texture and a fine French flavour.
  • Cobra: Produces huge deliciously tender and tasty crops of exceptional quality beans.

How to achieve the best results

Improve plant health with Bio-Gro Plant Health Invigorator to suppress insects, pests and fungal diseases and boosts vigorous healthy growth.

You May Also Need

Protect your young plants with Insect Netting. Use Pea & Bean Net between canes for added growing support. Pre-dig the soil with our lightweight, dry Organic Extra Natural Farmyard Manure.

Why not grow runner beans and French beans from seed, The Marshalls windowsill propagator kit, has everything you need to get started.


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