How to Grow Runner Beans

Runner beans, Phaseolus coccineus, are a wonderful crop for those growing in a polytunnel or outdoors in a garden. They are well-suited to cultivation in the UK climate and typically provide an abundant harvest – so abundant in fact that many gardeners wonder what to do with all the runner beans that they grow.

Runner beans are typically grown for their green pods, which are used as a vegetable. But the beans inside the pods can also be left to mature fully and can then be harvested, dried and used as a pulse.

As well as being a great edible crop, runner beans are also highly ornamental – prized for their pretty, typically scarlet, flowers. They can look very appealing whether you grow them in a polytunnel, or elsewhere in a vegetable garden.

Choosing Runner Bean Varieties to Grow

When growing runner beans you will have a lot of choice about which variety or varieties you grow. There are numerous options to choose from. Some are vigorous and tall plants, while others are dwarf cultivars, better suited to small spaces or container cultivation.

A good place to start when choosing runner beans is with varieties that have received an award of garden merit from the RHS:

• ‘Achievement’ (H2)
• ‘Aintree’ (H2)
• ‘Benchmaster’ (H2)
• ‘Celebration’ (H2)
• ‘Enorma’ – Elite (H3)
• ‘Firelight’ (H3)
• ‘Firestorm’ (H2)
• ‘Greshen’ (H2)
• ‘Liberty’ (H2)
• ‘Moonlight’ (H2)
• ‘Red Rum’ (H2)
• ‘St George’ (H2)
• ‘Stardust’ (H2)
• ‘White Lady’ (H2)

Of course, this is just the beginning and there are numerous interesting and useful varieties of runner beans that you might consider.

Some are also ideally suited to growing for shelling beans rather than for the green vegetable, so that is something else to consider when deciding which variety to grow.

Runner bean seeds are widely available online, or from local garden centres or plant nurseries. Sometimes, plug plants can also be purchased to plant out once the weather warms, if you have left things a little late to grow your own from seed this year.

As you prepare your garden and yourself on how to grow runner beans, make sure you know how to keep rats out of your garden to prevent these pests from ruining your crops.

Where to Grow Runner Beans

Runner beans will require full sun, and a sheltered position. As climbers, they will need some kind of support so this should of course be factored in when you are making a decision about where they should be grown.

Remember that you might grow in containers or in the ground, but dwarf cultivars will be best for container growing and this will still take more work than growing in the ground.

In the ground (or in raised beds) runner beans will be very at home in a traditional vegetable garden or allotment. But with their attractive flowers and form, they can also look great among flowers in an ornamental and edible part of the garden.

You might use them to create a division between different garden rooms, along a sunny garden boundary, or growing up the side of a pergola, gazebo, or other garden structure.

Fertile soil or growing medium is also very important. The soil or medium must be consistently moist through the growing season and yet free-draining. It should contain plenty of organic matter. So before planting, be sure to prepare the area with plenty of homemade compost or well-rotted manure. A slightly acidic growing medium with a pH of around 6.5 is ideal for a good crop.

Traditionally, gardeners created a runner bean trench to prepare for planting this crop. But runner beans can also be grown in any fertile raised bed, or in pots. If growing in containers, note that dwarf types need a container at least 30-45cm wide, and larger climbers will need one at least 75cm wide and 45cm deep.

Another thing to think about when deciding where to grow runner beans is crop rotation.

As legumes, runner beans are nitrogen fixing plants, and can ensure that there is nitrogen available in the soil for crops that follow them in rotation (and perhaps for companions growing close by). So you should move them throughout the different beds or growing areas in your garden.

Sowing Runner Beans

Runner beans are typically either sown indoors in April or May, or direct sown in the polytunnel or outside in the garden in May or June.

If sowing indoors, sow beans into small pots or toilet roll tubes filled with a suitable moist yet free-draining, peat-free seed starting potting mix, around 5cm deep. Keep them watered and in a warm, bright place where temperatures remain above 12 degrees Celsius. Seedlings should germinate and grow quickly.

Since runner beans are tender plants, it is important to keep an eye on the weather forecast for late frosts and to make sure that you do not plant out your runner beans too early. They can be killed by a late cold snap if you plant out too soon.

If sowing outside or in your polytunnel, make sure all risk of frost has well and truly passed before you do so.

The soil must be at at least 12 degrees C. for seeds to germinate successfully. Again, sow 5cm deep, with two seeds at the base of each support, which should be in place before sowing or planting out.

Runner Bean Support Ideas

Remember, you will need to have suitable supports in place before you sow or plant out your runner beans. Climbing beans will always need tall supports up which they can twine.

Runner beans are traditionally grown on a-frames made with tall bamboo canes or natural branches, tied together at the top. Create two rows of canes or wood branches around 45-60cm apart, spacing each cane or branch around 15-30 cm apart. Then tie pairs of canes together at the top, with a horizontal cane or branch across the top to create a sturdy framework.

Alternatively, you can make an X frame support, by crossing and connecting the canes lower down. This takes up more space but the beans are easier to pick and cropping can be better.

If space is limited, you can grow a few runner beans on a wigwam-like structure of canes or branches, either in a bed or border, or in a patio container. With dwarf beans in pots, twiggy sticks like those used for pea supports could be enough.

Caring for Runner Beans

Runner beans require consistent watering throughout the growing season, and will need even more watering when grown in pots. Water regularly, especially once the plants flower and form pods.

Mulch around your runner beans in July with organic matter, to help reduce evaporation from the soil, and to provide slow-release nutrients too. A good quality organic mulch should also reduce weeds.

Once runner beans reach the tops of their supports, nip off the growing tips. This should encourage side shoots to form lower down on the plants. Tie in stems that are not twining and attached properly to supports.

Make sure to learn how to layer and mould layer herbs too.

Harvesting Runner Beans

The main harvest from runner bean plants will typically be the green pods, before the beans inside them form fully. But remember, you can also grow runner beans for the beans to shell, dry and use as a pulse. These are a very useful and protein rich addition to your homegrown diet.

Runner beans (the green vegetable) are typically picked from around midsummer, for a period of around 8 weeks if you keep harvesting on a regular basis.

You should harvest the tender young pods when these are around 15-20cm long, at which point they should not yet have developed tough strings. They should snap easily and the beans inside should be pale, and still fairly small.

Make sure you harvest any beans that are ready every 2-3 days, so that no pods reach maturity, since once they do, the plants won’t produce any more.

These can be used up in a wide range of recipes. So as well as freezing or otherwise preserving your beans, you might also use them up in many ways to serve to your household.

If you wish to grow runner beans for shelled beans, allow the pods to mature fully and fill out with the beans inside. Allow these to remain on the plant until they turn brown and dry out, and the seeds can move around inside.

The shelled beans can be dried and used as a pulse. They will need to be soaked and boiled for a long time before they are used. If you have a pressure canner you can also put up the beans in jars so that they are ready when you want them later in the year, but will remain shelf stable for at least a year or so’s time.

Pests and Diseases

• Protect runner beans from common pests like aphids and slugs by taking preventative measures and using organic pest control methods.
• Monitor the plants for signs of diseases, such as chocolate spot or powdery mildew, and address them promptly.

Crop Rotation for Runner Beans

Rotate the location of runner beans each year to minimize the risk of disease and improve soil fertility.

Avoid planting them in the same spot for consecutive years.

What to do if runner beans fail to set pods

Runner beans thrive in the UK and typically face minimal challenges. However, gardeners may encounter issues with pod setting, especially early in the season. Here are some common factors that can contribute to this problem:

Insufficient moisture at the roots during the critical watering period, often caused by high temperatures. To address this, ensure regular watering and apply mulch made from organic matter.

High night temperatures can hinder pollen production and result in fewer pods. Fortunately, as temperatures cool down, this issue tends to resolve itself.

Acidic or poor-quality soils may hamper crop production. It’s advisable to prepare the soil adequately before planting runner beans.

Cold and wet summers can lead to a scarcity of pollinating insects, but this situation typically improves when weather conditions change.

Birds may peck at the flowers, causing damage. To deter them, consider hanging bird scarers made from tin foil or old CDs among the canes.

Learn How to Grow Runner Beans Today in the UK

If you think about all of the above and position and care for your runner beans correctly, you should be rewarded with abundant harvests later in the year, as this is a crop that tends to thrive here in the British Isles.

Fancy growing more vegetables in your garden? Try our go-to how to grow coriander guide.

FAQs

References:

Royal Horticultural Society. (n.d.). AGM fruit and vegetables. Available at: https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-fruit-and-vegetables.pdf [accessed 07/07/23]

Dobies. (n.d.). Runner Bean ‘Mergoles’. Dobies. Retrieved from https://www.dobies.co.uk/runner-bean-mergoles_mh-37995 [accessed 07/06/23]

Kings Seeds. (n.d.). Runner Bean ‘Lady Di’ (Phaseolus coccineus). Kings Seeds. Retrieved from https://www.kingsseeds.com/products/vegetable-seeds/beans/runner-bean-lady-di-ppp-aphaseolus-coccineus-bgb40557-clot-see-pkt-dgb#:~:text=Description&text=Runner%20Bean%20seeds%20%22Lady%20Di,and%20have%20red%20colourful%20flowers. [accessed 07/06/23]

Thompson & Morgan. (n.d.). Runner Bean ‘Celebration’ Seeds. Thompson & Morgan. Retrieved from https://www.thompson-morgan.com/p/runner-bean-celebration-seeds/307TM [accessed 07/06/23]

Mr Fothergill’s. (n.d.). Runner Bean ‘Armstrong’ Seeds. Mr. Fothergill’s. Retrieved from https://www.mr-fothergills.co.uk/Runner-Bean-Armstrong-Seeds [accessed 07/06/23]

Acquagarden. (n.d.). Runner Bean ‘Red Rum’ Large Plant Pack. Acquagarden. Retrieved from https://www.acquagarden.co.uk/products/runner-bean-red-rum-large-plant-pack [accessed 07/06/23]