Growing runner beans in any size garden may be easier than you think. They establish themselves quickly, produce a plentiful supply of greens, and also add nitrogen to the surrounding soil. Some varieties also introduce a splash of colour to any veg patch or flower border. Here is a guide to getting the most out of your runner bean plants this summer.
Growing runner beans from seed – which way up?
Runner beans are best grown from seed during the month of May. This is the most cost-saving way of producing plenty of plants, provided you have a way of protecting them from the risk of frost. The only time you will ever catch me buying runner bean plants from a garden centre is when I have missed the opportunity to grow them from seed.
You can avoid germination issues by ‘chitting’ your beans. Evenly space each bean on a damp cloth or paper. Seal them in an airtight container and place them in a warm, dry, and dark spot. An airing cupboard is a perfect place to germinate your beans. They will need checking daily! As soon as they start to germinate, place each bean individually into pots of good potting compost. This can also be done when the roots are about 1 inch long. Place them in a warm, sunny position to grow on. Sprouting runner beans will find their own way up. If you are planting directly into the ground or you are growing runner beans in pots, then plant each bean into a 2-inch deep hole and cover with compost or soil.
Hardening off
Hardening off is essential. Whether you have grown your plants from seed or bought them from a garden centre, you will need to harden off your runner beans before planting them out. Do this after the risk of frost has passed. If you plant too soon, the sudden change in temperature could weaken or even kill them.
Start off by placing your plants outside in the middle of the day for a couple of hours. Gradually increase the amount of time each day. After a minimum of two weeks, your plants should be strong enough to be planted out.
Preparing the ground
Your plants will benefit from good soil – plenty of organic matter and a general organic fertiliser.
Runner beans like the ground to be slightly moist. Dig a 10-inch trench under the site where you intend to plant. Line the bottom of the trench with sheets of newspaper to retain as much moisture as possible. After this, pour a couple of buckets of water into the trench before back-filling it.
Providing support
Most people prefer the traditional method of building an 8 ft high ridge frame for supporting runner bean plants. This involves placing sticks or bamboo canes in vertical rows a few feet apart. The tops are then tied together and fastened with horizontal supports. I use this method myself, but there is no harm in being creative.
You could try supporting your beans over wigwams, and trellises or even have them climbing up and over a shed or garage. As long as the bean plants have something to coil around and are planted in a rich and deep soil, they should be happy.
Planting runner bean plants out
Now that the growing site is ready, ensure that the soil is nice and loose using a garden trowel. Before planting, I like to gently loosen the roots by ‘tickling’ them. This will encourage your runner beans to leave the confines of the pot-shaped compost ball and branch out into the surrounding soil. Plant your runner beans, one every foot or so along the line of your supports. Water well until fully established.
Aftercare & cropping
Ensure that your plants are twining around the supports. Loosely tie them into place. This will be helpful to encourage each plant to find its way up the canes.
How tall should i let my runner beans grow? As soon as your runner bean plants reach the top of your supports, cut or ‘pinch-out’ the top shoots to encourage growth lower down. This will make for a much heavier crop. The cut end of the plants will continue to push upward for a while.
Pick your young beans on a regular basis to encourage more growth. If you leave them too long, you will find that the beans will become stringy and too tough to eat. Picking encourages the production of more flowers, giving you more beans over a longer period. I would suggest you harvest your beans on a daily basis if possible.
How long do runner beans take to grow? If you sow your runner beans during May, you should expect a crop two months later in July.
Growing runner beans from last year’s beans: Firstly, I should point out that you will not be able to grow beans on from an F1 hybrid. You need open-pollinated seeds. Leave each bean out to dry in a bright, cool position. Don’t use any heat! Then, label and bag them up. They will keep for a couple of years.
Growing Runner Beans in Pots
Perhaps you have limited space, or have a balcony garden? No problem. You can successfully grow Runner Beans in 10-inch pots filled with a good, general-purpose compost. Try growing them in batches of 10-12. Group the pots close together and push a 6-8 foot pole in each. Tie garden twine between each pole, bringing them together to form a trellis or wigwam around the pots. Runner beans will happily grow up string. Just ensure whatever structure you build, can withstand the weight of the plants, and is wind resistant.
Feed your potted runner beans once a week with a general liquid fertiliser. Later, when they start to flower, move on to a Tomato feed. You will need to regularly water your runner bean. Runners are very thirsty plants and you should water them first thing in the morning and last thing at night. You may need to increase the watering during hot, dry weather. However, don’t let them sit in water. Keep well drained.
Take away:
- 10-inch pots
- Good quality compost
- Feed once a week with tomato feed
- Water at least twice a day
When to Harvest Runner Beans
Harvest your bean pods while they are still flat, just before they become plump as the beans inside form. Sizes for maturity can vary, but 5-7 inches long is normally the correct size to look for. Don’t try to pull the bean pods off. This may damage your plants. Instead, use a sharp pair of scissors or secateurs. Mature and fully formed beans do contain a toxin which can be harmful if eaten in larger quantities. If you do find mature beans, cut them off and add them to the compost heap. This will encourage more bean development
Take away:
- Harvest when pods are 5-7 inches long
- Before beans form inside pods
- Don’t each mature beans
Pests & diseases & Runner bean problems
Aphids
Aphids are a common nuisance when growing runner beans. Blackfly and greenfly can stunt the leading tips and introduce other diseases. As soon as they appear, spray the aphids with the following organic solution:
- Finely chop a couple of rhubarb leaves.
- Boil them in water and simmer for about five minutes.
- Once cooled, add several drops of environmentally friendly washing-up liquid to the brew.
- Keep the solution in a cool, dark place out of the reach of children.
- Spray on each plant on the first signs of infection. Ensure that you spray beneath the leaves. Try not to breathe in too much of the mixture!
WARNING! Rhubarb leaves contain high doses of Oxalic Acid which is very harmful to humans (and aphids) if consumed.
A simple alternative to this recipe: a weak mixture of washing up liquid and water in a mist sprayer.
Slugs & snails
Slugs and snails can rapidly devour your young runner bean plants as well as damage maturing beans. Here are a couple of methods for controlling slug and snail damage.
- Place collars over your young plants. You can make your own by cutting lengths of drainpipe or top and tailing plastic bottles. I also wrap copper tape around each collar as slugs and snails hate crossing this metal.
- Use organic slug pellets. I’d highly recommend ‘Doff organic Super Slug Killer‘. It contains Ferric Phosphate and is harmful to slugs and snails only. You can also grow it with edible crops and it actually fertilises the soil. Be careful not to overdo it; leave some slugs for the birds!
- Dispatch slugs and snails by hand. This may be unpopular, but still the best method of control. Go out with a torch and a sharp knife at night. The rest, I’ll leave to your imagination. This method is most productive during damp weather.
Flower loss
This can be the result of a lack of pollinators (bees). Grow plenty of bee-friendly flowers to encourage more in your garden. Flower drop can also be the result of your runner bean plants drying out. During dry weather, ensure on a daily basis that your plants have enough water.
Other rare or minor issues to look out for
- Shield bugs – Can reduce the growth as they drink sap from your plants.
- Halo blight – Leaves turn brown and fall off on young plants. Best practice is to remove infected plants and replace them. This disease does not stay in the soil for long.
- Seed rot – This is commonly caused by low temperatures during seed planting. Runner bean seeds need a minimum of 10°C / 50°F for germination.
Strong varieties to grow this year
- Runner Bean ‘Moonlight’
- Runner Bean Scarlet Empire
- Runner Bean ‘Enorma’
- ‘White Lady’
- ‘Wisley Magic’
- ‘Goliath’ Heritage
- ‘Crusader’ Heritage
- White Apollo
Recap
- Keep your running beans warm during cold weather. Minimum temperatures of 10°C / 50°F.
- Plant out after the risk of frost has passed in a sunny part of the garden.
- Provide your runner beans with plenty of support.
- Guard against slug and snail damage. This is especially bad during damp weather.
- Pinch out the leading growing tip as soon as the plant reaches the top of your canes.
- Ensure that your runner bean plants don’t dry out. Keep the soil moist.
- Be on the lookout for aphids. Treat your plants as soon as they appear.
- Pick your runner beans on a regular basis and don’t let them get too big. Big beans will be very stringy!
- Enjoy lots of bean-based dinners for the next couple of months!