How to Grow Runner Beans
Runner beans are delicious, full of nutrients and one of the easiest vegetables to grow. Picked fresh, they’re far more tender than any you can buy - and the flowers add a colourful display to your garden. Here’s how to grow them.
Most common runner bean plant questions
When can I plant runner beans?
Runner beans are best planted outside from late May through to July.
Plant after the last frost has passed.
What soil is best for runner beans?
Runner beans need fertile, well-draining soil.
A good mix to use is three parts quality compost and one part topsoil. Rake this in the ground or mix it together if you are growing in a pot.
If possible, add a layer of well-rotted manure to the soil in the previous autumn and allow that to mix in to add nutrients and also improve the soil’s texture.
How much sun do runner beans need?
Runner beans need full sun.
Plant them in a position where they will receive around 6-8 hours of direct sunlight every day.
Planting runner beans
Plant runner beans about 20cm apart.
Runner beans are best planted in rows where several can grow together but they can also be grown in containers. When growing in pots choose a larger pot, that is at least 20cm wide and 20cm deep. The larger the pot, the more moisture it will retain which is important when growing vegetables.
Rake the soil and remove any weeds if you are planting in the ground, or simply fill your pot up if you are planting in a pot. Dig a small hole large enough for the roots to fit in and then pop in your plants. Back fill any gaps with soil and then gently firm the plant in with the tips of your fingers. Give the plant a watering to help the soil settle around the roots.
If you are planting with pots then always ensure that they have drainage holes. If the water sits in the pot this will cause the roots to rot and quickly lead to plant death.
How to support runner beans
Runner bean plants will need to be supported and grow vertically.
This can be done by training the plants up an A-frame (read below for instructions) or trellis.
Your support will have to be at least 2m tall (runner bean plants can grow in excess of 2.5m). The plants should grow tendrils that will reach up and start climbing the structure. You can aid this process by gently wrapping the new growth around the support structure to help it to cling on.
An A-Frame is a structure that consists of at least two support arches with another beam (usually just a stick in this instance) laying across the top. The arches, when it comes to A-Frames used in gardening, are usually two sticks, such as bamboo, planted around a foot or so apart with their top ends tied together to make what looks like a very long triangle.
You will want one of these arches every 20-25cm when growing beans, in the end forming a row of arches. The runner bean plants will climb up the poles to the top. To help with this process and to give them even more support, you can tie rows of string around the arches every foot or so. This will be an extra something that the plants can grab onto as they are climbing up.
How much water do runner beans need?
Runner beans need to be watered regularly so the soil is kept consistently moist.
During hot summer days this means at least once a day. If you are unsure, touch the soil and if it is dry a fingernail deep then give the plant a watering.
If you are planting runner beans in containers then it is especially important to ensure the plants are adequately watered. This is because there is less soil to retain the moisture.
How to feed runner bean plants
When the plants begin producing flowers, give them a high-potash feed every week.
A feed such as liquid tomato fertiliser works well.
Potash, or potassium, is one of the three main elements in fertilisers along with nitrogen and phosphorus. Potash in particular supports growth of flowers and fruit and so this feed is often increased as the fruits or flowers are beginning to form.
How to harvest runner beans
Once planted, your plants should be producing runner beans ready to harvest in about 10-13 weeks.
You can harvest them when they are around 15-20cm long.
To harvest the runner beans simply pinch them off of the plant at their base. Do this gently so as to not damage the rest of the plant.
The more proactive you are in harvesting the beans when they are ready, the more beans your plant will produce. Picking the beans will prompt the plant to produce more so be sure to watch your plant closely as it begins to crop for a maximum yield.
Common runner bean plant problems
The most common runner bean pests are aphids, slugs and snails.
Each of them attack plants to various degrees and are more dangerous at different stages of the plant's life.
If your plant has struggled to produce many runner beans, this is usually down to a lack of moisture and nutrients in the soil or not enough pollinating insects instigating the bean production process. Read below for more information on these specific problems and how to combat them.
Slugs and snails
To combat slugs and snails, try watering in the morning which will give the water time to evaporate off the surface during the day before they come out at night.
Remove any debris, logs, old pots, or anything else they can hide under during the day and keep the area around the plants clean.
The second form of protection against slugs and snails is to form a barrier around your plants. This can be done with copper wire which reacts with the mucous or with crushed egg shells which will cause cuts and lead to them drying out. Ensure the plants are not touching any objects such as walls or other plants which can form a bridge for the slugs to climb over to reach the plants.
Another good organic method to get rid of slugs is using nematodes. Nematodes are microscopic worms that essentially find slugs underground and cause them to die. They are completely harmless to other wildlife or your vegetables (or you when you eat your vegetables) and so are a great organic solution to slug damage. Make sure you read and follow the instructions on the packaging carefully.
Aphids are small green bugs that cluster on the stems, particularly at the joints, and also the underside of leaves. They cause leaves and beans to discolour and become misshapen. Aphids also leave behind a sticky residue known as honeydew which can then promote the growth of a fungus known as sooty mould.
To combat aphids you can spray your plant with soapy water. Garlic is another aphid deterrent so adding some garlic cloves to the water when spraying. Alternatively, you can just grow some garlic nearby which should have a good effect.
Ladybirds and hoverflies enjoy eating aphids so planting marigolds, which attracts ladybirds and hoverflies, nearby will help control the pest. If you have a serious infestation you can also buy specialist chemical sprays which will get rid of aphids.
Poor bean production
If your plant has grown tall but failed to produce many beans then there are three main reasons for this: lack of water, lack of nutrients, and lack of pollinating insects.
Ensure that your soil is nutrient rich and has a good, crumbly texture. If you are planting in the ground then make sure you mix in plenty of well rotted organic matter such as quality compost. Then make sure the water is kept regularly moist. Remember to feed the plants a high-potash feed every week once the plant has started to flower.
To attract pollinating insects into your garden you will want to have plenty of pollinator friendly flowers in your garden. Lavender, foxgloves, heather, abeliam, monarda are all fantastic flowers that will attract the bees you need to pollinate your runner bean flowers to help the pods develop.