When planning to grow runner beans there are a few things to bear in mind before you start. You will need enough plants to feed you but not so many you drown in them. As a guide 16 plants will provide enough food for a family of 4 across a 5-6 week period and at the height of the cropping season you will have spare beans for storing. The plants grow to at least 2 meters tall if you let them so plant them where they will not shade out your sun loving plants. The plants will need watering regularly, make life easy on yourself if possible and think about how far you’ll need to carry a watering can. Check the seed packet for any special instructions.
To be truly successful it is best to do a bit of soil preparation. Runner bean plants are hungry and thirsty plants so get some compost dug in to the area you plan to grow them in, this will help feed your runners and hold water for their roots. Runner bean plants like a lot of water, especially once they start to produce the long bean pods, they may need watering daily when it is dry.
You will need a wigwam or double row of supporting canes. For a wigwam to support 8 plants you will need 8 x 2 meter canes or similar sized poles and some garden twine. Evenly space the poles in a circle approx 1 meter in diameter and push them into the soil approx 20cm. Tie the canes together approx 20cm from the top using garden twine. For a double row to support 8 plants you will need 9 x 2 meter canes or similar and some garden twine. Mark out two rows approx 45 cm apart. Using 4 canes per row push the canes into the soil approx 20cm deep and 15 – 20 cm apart. Cross each pair, one from each row, at the top, lie the spare can along the crossover point of all 4 pairs and tie in each pair securely with garden twine.
Sewing the seeds
There are 4 ways to get your plantlings going;
- The seeds can be started off indoors if you want to get your crop off early. It is best to use a deep paper pot or loo roll middle filled with compost. Stand the pots in a tray on a sunny windowsill and keep the soil damp, the plants will soon start to show.
- If you want to plant outdoors and there is the risk of frost put the trays of pots in your greenhouse or a cold frame, the plants will be slower to germinate and slightly later to flower than the indoor seedlings but just as healthy.
- Sew your seeds directly where you want them to grow after the risk of frost has passed, sew 2 seeds per cane. These plants will bear flowers and fruit later still and is a good approach if you want a second crop, just don't have space to grow the seeds indoors/under cover or don't get around to sewing your seeds until later in the season
- Take the more expensive route and buy seedlings from the garden centre or farmers market. This is particularly necessary if you have a healthy crop and it suddenly gets ravished by the local wildlife
Maintaining healthy plants
Plantlets grown indoors will need to be hardened off when ready for the big outdoors. They are ready once they reach approx 15cm tall. Put them out in a sheltered place and protect or bring back indoors over night for a week or so. Plant them next to their supporting pole and loosly tie them to it, at this stage it is worth putting a few seeds in the soil just in case you loose a few plants. When sewing seeds directly into the soil loosely tie the young plantlet to it’s pole when it is 10 - 15 cm tall if it has not started twining on it's own, N.B.the tips sway as they grow and twine around anything they come across so you may find they don't need help.
Your plants will be fairly self sufficient until the flowers have been fertilised and the young beans appear. At this point you will need to start watering regularly, every day if it is really dry.
Hints and tips
- If you want to watch the plantlings grow roots with your children use a clear glass jar or container lined with blotting/absorbant paper, place the seed between the glass and the paper and place in a light warm place out of direct sunlight, keep the paper damp at all times and see what happens.
- If you are looking for plantlets rather than growing from seed check out your neighbours, the local car boot sale or plant sale. Keen veg growers usually have spare plants to sell or pass on, we hate throwing healthy plants away.
- The biggest risk to your young plants are slugs unless you have rabbits or deer living nearby. Plant a few extra seeds to in fill any gaps.
- If you really love runners and have space for two batches plant an early crop and then a late crop three to four weeks later, this extend your picking season.
- The sooner the young plantlets start to twine the earlier they will gain height up the support and produce flowers, so if they don't twine tie them in.
- Runner beans are thirsty plants, once the pods start to show you should water the plants regularly, especially if there is little or no rain.
- Pick regularly as once the seeds start to ripen in their pods the flowering mechanism switches off and your plants will stop producing.
- The roots hold nitrogen, feed the soil when the plants have finished by digging in the roots and base of the plant stems.