HOW TO SOW AND GROW RUNNER BEANS IN THE UK
Runner beans are one of the most reliable vegetables to grow in the UK. They will not only produce a delicious crop of beans with very little effort but they will also produce a delightful display of flowers in July time.
We recommend sowing the seed indoors / under cover and then transplanting them outside when the seedlings have emerged. Runner Beans can also be sown directly in the soil when all danger of frost has passed (end May / very early June 2017). The problem with direct sowing is that the seeds are a great delicacy for mice and other small animals! Wet weather can also rot the beans.
Dates for sowing seed are the same for dwarf and climbing varieties.
To adjust the calendar dates for your town, click here.
Start saving inner cardboard tubes from toilet rolls – early January
Sow Runner Bean seeds in pots indoors the first week of May
Sow Runner Bean seeds under cloches the first week of May
Harden off Runner Bean seedlings the third week of May
Sow Runner Bean seeds outsideend May / very early June 2017
Plant out seed sown in pots indoors the last week of May
Begin to harvest Runner Beans –the second week of August
Be sure to read our section on runner bean varieties before buying seeds because in the last five years there have been great improvement in the available varieties (we explain in detail on that page) and many web pages and books have not yet got round to understanding this.
BEST SOIL AND POSITION FOR GROWING RUNNER BEANS
Runner Beans do best when they are grown in nutrient rich soil which retains moisture. Their roots go down much deeper than most vegetables so a well dug soil to a depth of 45cm / 18in will suit them fine.
The classic way to prepare soil for growing runner beans is to dig a deep trench as long as the proposed planting area, about 60cm / 2ft deep and about the same width. Stack up the dug soil at the side of the trench. This would normally be dug around November time.
Over the next month or so kitchen waste, which would normally go on the compost heap, is placed into the trench instead. This continues until the trench is half-filled, hopefully around Christmas time.
Now fill the trench with the earth previously dug up and place the remaining earth on top. This will create a mound of earth over the trench which will settle down over the next couple of months. In the end, at May / June time you should end up with a small mound over the trench which is ideal for planting your Runner Beans. The kitchen waste below the soil will have rotted down nicely to provide top quality body, nutrients and drainage to the soil.
The above is the ideal, and it really does produce a bumper crop of runner beans but if you are reading this article in May / June time then of course it's too late. But at least you will know what to do next year! If time is at a premium then dig the soil well and add a good dose of blood, fish and bone at the rate of two handfuls per square metre / yard.
Runner Beans are not particularly fussy about sunlight. Shade all the time won't suit them but partial shade or full sun will do equally well. You do need to remember that a 1.8m / 6ft wall of foliage will cast a considerable shadow so consider carefully other plants nearby when deciding where to grow your Runner Beans.
It is a common misconception that Runner Beans need full sunlight and heat all the day, in fact too much sun and heat can cause them to fail to set a crop even though they may produce lots of flowers. This may or may not be a problem for your depending on the weather conditions in your area.
In a four year crop rotation plan runner beans are included with others of the bean (legume) family. In reality however they cause very little build up of problems in the soil and can be grown anywhere. For convenience sake many gardeners erect permanent supports for runner beans and grow them in the same position year after year with no ill affects. This subject of beans and crop rotation is discussed in more detail
Having prepared the soil as described in the previous paragraph decide which of the three methods below you want to use to sow the beans. Consider also the possibility of buying garden centre raised seedlings and planting them out in the last week of May. Although the choice of varieties will be restricted this method does bypass lots of the work of raising the plants from seed.
A key point to remember when sowing runner beans is do NOT start them off too early, especially important if you start the beans off indoors. This is a common mistake made by those eager to raise an early crop. Runner beans will be killed by even the smallest hint of a frost so they must be planted out only when all danger of frost has passed – see the calendar above and the methods below for specific dates (customise those dates your area by clicking here).
Combine that with the fact that when runner beans have germinated they grow tall very quickly and start to become unmanageable in pots indoors after much more than two to three weeks. See the two pictures below.
The runner bean seedling above was sown only nine days before this picture was taken. It shows just how quickly this vegetable develops when sown indoors.
The picture above however shows the roots of the same plant and illustrates just how quickly they have grown. This plant will need to be potted up in three to four days time.
Runner Beans need a soil temperature (that's not the same as the air temperature) of around 10°C / 50°F or higher to germinate, which is on the low side compared to many other vegetables. They will take roughly a week to appear after being sown.
SOW RUNNER BEANS IN POTS INDOORS / UNHEATED GREENHOUSE
This is the most reliable method because the seedlings will not be attacked by mice, slugs or snails at the early stage of their development. Slugs and snails can easily decimate your entire crop at the seedling stage. Start sowing beans in pots indoors during the first week of May The germination rate is exceptionally good using this method.
As soon as the beans germinate they will begin to sprout roots which are longer and quicker growing than most other vegetables. For this reason we recommend that you use taller pots compared to the normal ones if you plan to keep the plants in the pots for much longer than a fortnight.
The inner cardboard tubes from toilet rolls are ideal for this purpose although you may need to start collecting these a couple of months before using them to have the correct number – friends and family always seem to willing to help in this task!
We have put a reminder in the calendar near the top of this page as well as in our combined vegetable growing calendar. If you have no long type pots / tubes then a standard 10cm / 4in diameter pot is the next best.
Take a 10cm / 4in pot, fill with multi-purpose compost to just below the top. Make a hole about 5cm / 2in deep in the compost, drop the seed in and cover with compost. The procedure is the same when using toilet roll cardboard inners.
However, first fill a seed tray with compost and then set the toilet roll inners 2cm / 1 in into the top of the compost before filling them with compost. Your average seed tray can take about 15 tubes. In this way when the roots reach the bottom of the tube they can then spread out into the compost in the seed tray.
Keep the compost moist and place the pot in a warmish place (dark or light). Keep a watch on the pots daily and immediately the seedlings appear (roughly seven days after sowing indoors) move the pots to a light and airy windowsill or a frost free greenhouse.
The roots especially on newly sown runner bean plants develop extremely quickly and about one week after the seedling appears above the compost they will need to potted on into a larger container. A 15cm to 20cm (6in to 8in) wide pot is the correct size and the plants should be OK for a week or two longer.
A week or so before the runner beans are to be planted outside in their final positions they will need to be hardened off. The purpose of this is to acclimatise the plants to outside conditions.
Before planting the hardened off beans in the last week of May you need to put up the supports (1.8m to 2.4m bamboo canes) which they will need later on. All manner of methods are used the commonest being:
- a pyramid shape where 6 or so bamboo canes are arranged in a circle tied together at the top, 60cm / 2ft in diameter with two plants at the base of each cane.
- another classic is the simple arch where the two rows of canes are spaced about 60cm / 2ft apart at soil level and tied together at the top.
- to avoid congesting the top of the supports two rows of canes can be arranged upright and supported by cross bars
A pyramid of runner beans
To plant the seedlings dig a hole just slightly bigger than the pot / cardboard tube. When using the cardboard tubes, plant the whole thing in the soil and firm gently around it. The cardboard will soon rot down allowing the roots to expand near the surface. For the pots, turn out the the plant from the pot and plant it in the soil. Water well whichever method is used.
SOWING SEED DIRECTLY IN THE SOIL OUTSIDE
Sowing the beans outside is simply a matter of erecting the supports (see above) and then sowing two beans at the base of each bamboo cane. The seed should be sown about 5cm / 2in deep. Water them in well. We don't really recommend this method because if the mice don't eat the beans, the slugs and snails will eat the seedlings as they emerge. The best time to sow outside is in the last week of May.
SOWING DIRECTLY IN THE SOIL UNDER CLOCHES
To gain the best use from your cloches place them out over the planting area two weeks before sowing the beans. This will warm up the soil to a surprising degree. Sow the beans exactly as described above, however the supports can only be erected after the cloches have been removed (about two weeks after the seedlings emerge). If the weather becomes unusually warm, remove the cloches during the day to allow air to circulate. Remove the cloches permanently, four weeks after sowing.
GROWING RUNNER BEANS IN CONTAINERS
Dwarf runner beans grow very well in containers as long as you keep them well watered. They may require watering twice a day in warm weather although there are a couple of things you can do to reduce this. There are two key varieties of dwarf runner beans which are widely grown and with good reason.
Pickwick is the well established favourite and it rarely fails. Lots of beautiful orange flowers followed by a very decent crop of stringless runner beans. Highly recommended.
A more recent variety is Hestia which produces a very similar crop of stringless beans but has the added benefit of producing red and white flowers. again, highly recommended.
The next consideration after choosing a suitable variety is which container to grow it in. As with many other vegetables, the larger the container the better. Larger containers reduce the need for frequent watering. Our suggestion is that a container of 45cm / 18in per plant will be about right. Slightly smaller is OK although you will need to be very vigilant about watering in warm weather.
To reduce the need for watering a layer of stones or woodchip over the soil surface makes a remarkable difference by reducing condensation. If you plan to go on holiday for a week and can't persuade or don't trust a neighbour to water your plants the best solution is to move the container to a very shady position out of the wind. This will reduce their need for water dramatically and they suffer very little in these conditions for a week or so.
DIFFERENT TYPES OF RUNNER BEANS
The traditional runner bean (they have been grown in parts of South America for over 2,000 years) grows to around 1.8m / 6ft high and needs support and to be tied into those supports. Genetic mutations have occurred which resulted in dwarf varieties growing to about 45cm / 18in high and requiring much less support.
This article is concerned primarily with growing the taller growing runner beans although much of the cultivation methods are the same. Dwarf varieties are great as decorative plants but when grown outside the pods are so low to the ground that they end up being splashed by mud. They are however well suited to growing in containers.
When stored correctly in dark, cool and dry conditions runner bean seeds will keep well for three years.
COMMENTS / QUESTIONS LEFT BY OUR READERS
Sometimes our readers ask specific questions which are not covered in the main article above. Our
Runner Bean comment / question and answer page
lists their comments,
questions and answers. At the end of that page there is also a form for you to submit any new question or comment you
NEXT PAGE – HOW TO CARE FOR YOUR RUNNER BEANS