French bean – Phaseolus vulgaris
Runner bean – Phaseolus coccineus
Soy bean – Glycine max
Summer beans are a big subject! We also look at borlotti beans (Phaseolus v, Cranberry Group), a variety of common bean first bred in Colombia as the cargamanto, and sometimes called ‘cranberry bean’.
Another variation is the Lima bean (Phaseolus lunatus), also called butter and Madagascar bean. These beans are slightly larger than runners and super tasty, but they need a little more warmth than the other beans here.
All are legumes, in the plant family Fabaceae. Mostly they are grown for pods, through summer and into early autumn.
Some plants are dwarf and some climb, with bean pods of varied colour, shape and length. Many are suitable for ripening to dry, and we can then shell the seeds to eat as nutritious food in winter and beyond.
- Days from seed to first harvest: 55–70
- Best climate is temperate to warm and not too dry, especially for climbing beans.
They are all sensitive to frost so the harvest period is midsummer to early autumn, around three months. During this time you can easily have a surplus of pods.
Harvests of mature pods for dry beans happen through the autumn, and in wet autumns they may not be totally dry.
All harvests need to finish before the first frost.
Why grow them
Flavour is a big motivation for growing your own, plus the regularity and abundance of harvests over a long period. Bean pods gathered and eaten on the same day have a crunchy texture, while yellow pods are slightly waxy.
Soy beans are delicious harvested in a green pod, with soft yellow beans inside, of superb flavour. Their harvest period is late summer, and the harvest is called edamame. Soy beans’ Latin name was chosen by Linnaeus, from the Greek ‘glykys’ which means sweet.
- Shelled beans taste amazing too, for starters when you pick them to eat as fresh beans in early autumn. They are creamy and full of flavour, without any dressing or sauce. Especially the white Phaseolus, Czar.
Then, as long as they are fully dry before you put them in a jar, they store for many months, and have considerably more flavour than bought beans.
Suitable for containers?
The best type for containers is any dwarf French bean, just one per pot – pick carefully to keep it cropping over a long period.
There is a dwarf runner bean variety, Hestia, which sprawls a bit but does work for containers. Give it a little support, say 60 cm/2 ft sticks, otherwise beans at ground level may be eaten by slugs.
Conditions for success
As much as they need warmth to grow well, they also need sufficient moisture. When I lived in France, and we had a warm October when I could give plenty of water to the bean plants, they were some of the best of the year. They don’t like fierce heat, just warmth.
- Grow under cover for early harvests, for example with a transplant of dwarf French beans, three to four weeks before your normal outside transplant date. Ensure to remove these plants by midsummer, when it may be too hot for successful growth and at risk from red spider mite.
High temperatures are detrimental to runner beans, which do not set well in hot summer weather, such as above 30 °C/86 °F by day. Night temperatures not going below about 18 °C/ 64°F also result in flowers not setting.
Not setting means that flowers appear and then simply drop off before becoming beans. It’s sometimes claimed that this is from a lack of moisture in the air or a lack of insects, but it’s from too much heat, together with too little moisture at the roots.
Climbing beans also do not like too much wind, as you can see from the photo below, taken during a windy summer.
There are green, yellow, and purple pods to choose from. Some are flat and some round. Some have white seeds and others are coloured – check out suppliers of heritage varieties such as Real Seeds in the UK. I give just a few examples here.
French beans – dwarf
They are easy to grow, not least because you don’t need to give any support. However, they grow heavy with pods and risk falling over, sometimes with the main stem snapping at ground level in a sudden high wind. This is terminal and very frustrating!
Dwarf bean plants crop earlier than climbing ones but finish earlier too.
- I enjoy success with Cupidon and Safari (green pods), Orinoco and Sonesta (yellow pods), Purple Queen and Purple Teepee (purple pods). Yellow pods keep their colour in cooking and purple ones lose it. There are many other varieties to try.
French beans – climbing
Your investment in a support structure is repaid by not needing to bend so much when harvesting. Plants also crop for a longer period than dwarf varieties, so one sowing, of Cobra for example, can feed you for two months or more.
A good strategy is to start the year with a few dwarf beans, then follow with a slightly later sowing of climbing beans. Sow the dwarf beans in mid-April under cover, and the climbing beans in late May, either under cover or outside.
- Try Cobra for green pods, Neckargold and Golden Gate for yellow pods, and Cosse Violette for purple pods.
- Standard borlotti beans grow a lovely harvest, either for pods or dry beans; there are also dwarf varieties.
Runner or pole beans
These crop heavily and for a long period. In my part of England, they are a staple of many gardens from just one sowing, for bean pods all summer.
They can also be grown for dry seed, and the variety I recommend highly here (Czar) is white flowering and white seeded. Once you find some seeds and succeed a harvest, you will appreciate why I recommend them: for the amazing flavour. Summer and autumn need to be warm enough to enable both growing and maturing to dry.
- Scarlet Emperor and Enorma grow large green pods over many weeks.
- For dry beans, Czar grows lovely white ones, and also works for picking green pods.
- I hear from several gardeners that their harvests are now less good from certain varieties of runner beans which they have grown for many years, while they keep buying new seed from the same seed company. See below for my tips on saving your own seed, which is less easy for runners than French beans.
Grow these as for dwarf French beans – they need warmth and are killed by frost. Harvests in my temperate climate are small but feel worthwhile, thanks to the excellent flavour.
In a warm summer, the pods can dry enough for shelling beans – see below.
I have limited experience of varieties – in the UK, Green Shell is common and grows well. Siverka is bred for cooler conditions and produced less well for me.
There are two factors to consider: plants are killed by frost and also need sustained warmth, both to germinate and grow strongly. They need to grow fast.
- In spring, later sowings often succeed better because they grow smoothly and strongly, overtaking early sowings.
If you have the facilities, I recommend sowing under cover, even in summer, because it’s so much more reliable. Bean seedlings sown direct take up a fair amount of space, so it’s very worthwhile to sow them in just one module tray. This can provide enough transplants for a big area.
Also, you can pop seedling plants in between existing vegetables that are going to finish soon. We do this with overwintered lettuce for example. Garlic is another possibility.
The overriding need is for warmth: 20 °C/68 °F is a benchmark for healthy germination and early growth. Here in Somerset, for example, that does not happen outside until early or even mid-June.
Therefore sow outside in early June, or under cover around the middle of May/late spring.
Bean seeds are quite large, so under cover sowings need a 4 cm/1.5 in diameter cell. Cover with as much compost as seeds are wide, not long, and it’s fine to place the seeds on their sides rather than pointed up or down. Any way works.
- When I am confident of strong germination, I sow one seed per cell. Sometimes this is not the case and I sow two seeds per cell, then thin to the strongest if they both start growing well.
For outdoor sowings, an easy method is to make holes with a wooden dibber, then simply drop beans seeds into a depth of no more than 2.5 cm/1 in below the surface. You can then use the dibber to scuff the surface and fill in your holes.
There should be no need to pot on seedlings from module into pot unless, for whatever reason, the bed is not yet ready for your plants. Or perhaps you sowed too early and it’s still cool outside!
I advise getting seedlings out as soon as possible before they need potting on, for more rapid and successful growth. The photos below show how I popped in bean plants between or close to existing vegetables which were soon to be harvested and cleared.
Small is good. For dwarf beans, 5–7 cm/2–3 in high; for climbing beans, 10–15 cm/4–6 in is fine.
For early plantings, it’s all about warmth, and they cannot be made before the last frost date. A week or two after that date is better. This means the soil will have warmed, making growth more certain, and it’s also less likely that slugs will eat plant leaves. If bean plants are cold, they are weak, which invites pests.
Dwarf beans can be spaced as little as 30 cm/12in apart, or up to 37 cm/15 in for easier picking and a slightly longer cropping period.
You can grow climbing beans either in rows, or in circles called teepees. Best spacing between plants is 30 cm/12 in, whichever support method you use.
- A teepee can be any diameter between 90 and 135 cm/3ft and 4.5ft.
- If you are making rows, each one should be around 60–90 cm/2–3 feet apart. This allows just enough space to walk between each line of two rows, which grow up to a central line along the top, as in the photos below.
Use whatever sticks you can find, and sharpen the bottoms so that they slide into the soil more easily. Bamboo canes are slightly thinner and do not need sharpening, but always put the fat end in the ground. For rows, not teepees, you need a few other sticks to serve as horizontals at head height, and they can be less stout.
The verticals sticks are best 2.5– 4 cm/1–1.5 in diameter (roughly) and 2.5 m/8.2 ft long. You may need to use a crowbar, or equivalent, to open soil enough that wooden sticks push in a good 20 cm/8 in deep.
Support for climbing beans must be strong, and stable enough that they stand firm during high winds in summer. Around here the traditional shape of supports is a line of two rows, with sticks pointing towards the middle and making a V at head height. Another stick is placed in the V horizontally, and tied firmly where it meets the two side canes – see the photos below.
However, in windy places, this creates a barrier to wind and is more inclined to blow over. Teepees are more stable because wind can flow around them. You walk around teepees to find beans and discover that there are more hiding in the middle, in comparison to plants in lines.
The main time to give water is when flowering commences, and then water maybe twice a week, or every two days if it’s very dry.
For harvests of dry beans, do not water after you have seen a full set of bean pods and some swelling, usually by early autumn.
Climbing beans, with their many leaves, need more water than dwarf beans. Nonetheless, they all need a good soak whenever you water because they grow so fast, and will reward you with more beans in exchange.
Extra mulch to retain moisture?
A compost mulch is sufficient in temperate climates. Here I have experimented with undecomposed materials on top, and have not noticed a huge improvement. However, I would mulch if the climate was hotter and drier in summer. The miscanthus I spread on top of the compost above, around new plantings, made little difference.
You don’t need to do any thinning or pruning, with one exception. In late summer it can be worth pinching off any new shoots, stems and flowers, on plants that are for dry beans. This is because new bean pods forming in early autumn will not have time to fill their pods and mature the beans.
Once dwarf bean plants start cropping in early to midsummer, they can give huge amounts of beans very suddenly, in a flush for about two weeks. Then growth of new pods slows for another four weeks or so. Beyond that, there are still harvests, but of decreasing quantity and quality. Pods grow less straight and may have a stringy texture, with small seeds inside.
- Climbing beans crop over a longer period and give huge harvests in warm weather.
- Timings and methods for harvesting dry beans are different to those for fresh.
How to judge readiness
Pods are most tender at any stage before you see beans swelling inside them. However, if you continually pick French beans very small, which are called filet beans, you have a smaller harvest in proportion to the time you spend picking. Filet beans grow to full-size pods in just a few days.
For dry beans, the pods need to be yellow and preferably dry. However, if the weather is cool and damp, it can be better to pick beans when yellow and before they rot on the plants, then dry them under cover.
How to pick
The stalk of bean pods is woody and strong, so, when picking pods, be careful not to disturb plant roots or break off whole stems. You can use two hands, with one holding the plant stem, and the other detaching your harvest.
When to pick and how often
In hot weather, the pods mature very fast, from being tender to rather tough, and with some stringiness.
- For fresh pods, pick every two to three days, and search under leaves for hidden ones.
- For dry beans, the first harvest will be late summer; for runner beans pick every week through early autumn. A final harvest before frost will include some green pods, with beans which are delicious to eat at the time, rather than trying to dry them.
- Borlotti and French beans keep condition better than runners while drying. You can leave them all unpicked until most leaves are falling off and you can see a large number of dry pods. Then, while picking them all, separate out the few which are still soft, for eating immediately, and dry the rest in their pods.
Final drying and shelling of dry beans
The pods you pick for dry beans are often not fully dry, in which case there is a final stage of drying before you put beans in jars to store.
- For runner beans, we find it best to shell out the contents and lay them on trays on a sunny windowsill for a week or two.
- Borlotti beans are easier when you leave them unshelled, but again, lay them on trays in a sunny, dry place. Then you can shell them once the pods are cracking dry. See the photographs above and below.
Soy bean harvest for dry beans
When soy beans are still soft in the pod, with the pods more yellow than brown, or even green but swollen, the harvest is truly delicious. Boil them in the pod for three minutes, drain off the water, and sprinkle a little salt before eating. (Place the cooked pods in your mouth, then pull them slowly out with front teeth together, to extract the beans. Pods are stringy at this stage.)
Then, even in a temperate climate, pods quickly pass from the edamame stage to being quite dry and with hard beans. It’s a fair amount of time needed to hand-pick pods and shell out the beans.
At least the dry beans are also very tasty, way more so than soy beans you buy. They are also larger and slightly yellow. Plus you can keep them for seed because they do not cross-pollinate, from what I observe.
The process of saving bean seed is the same as for harvests of dried beans, explained above.
- A joy of saving seed for French beans is that they do not cross-pollinate between different varieties, nor do they need more than one plant for there to be viable seed. Therefore put a cane next to any plant you want to keep seed from, to remind you not to pick any of its beans. The result is a worthwhile seed harvest that has time to mature by early autumn because you did not pick any beans in the previous weeks.
- Runner beans do cross-pollinate, and if you grow more than one variety your seeds will not grow true. Best find a favourite and keep growing that one, because homesaved seed which is fresh germinates so much better than bought seed. Also, the plants will be better adapted to your climate and conditions.
- I find that borlotti beans do not cross-pollinate, but I am not certain that this is always the case. For example, whether dwarf Borlottis might cross with climbing ones, to produce an interesting result!
Which pests are likely, and when
These plants suffer few pests, except for slugs possibly eating new plantings, and blackflies sucking sap from the stems. In both cases, the remedy is to grow stronger plants.
- Do not use undecomposed mulches around new plantings if you are in a damp climate, and wait for sufficient warmth before transplanting.
- As soon as you see blackflies, spray the affected stems with water and water the roots as well. They should then diminish quite quickly.
New plantings in spring may benefit from a fleece or mesh cover, for protection from cold winds.
Once sticks are in place it’s difficult to cover plants. I am nervous if I see rabbits chewing the main stems of climbing beans, yet they regrow, without protection. Possibly because rabbits are not too numerous here, but it’s one to be aware of, and bird netting could help.
Other likely difficulties
Diseases are few, and the most likely problem is from beans not setting in extreme heat – see ‘Conditions for success’ above.
The dreaded pyralid weedkiller is highly damaging to bean plants. The photos below are to help you identify this potential problem. It can be in peat-free potting composts, made from garden wastes which were composted with lawn clippings from sprayed lawns. Yes, people do such crazy things, and the danger is invisible to us until our plants suffer.
Use a sharp knife or trowel to cut stems at ground level or just below, leaving most roots in the ground. There won’t be many nitrogen nodules by this stage because bean plants use most of them to grow themselves.
When we grow these plants for bean harvests, they are close to the end of their lives by the time we remove them. At this stage, they make no new nodules.
When clearing plants in autumn, rather than during the summer, I like to spread the annual dose of compost before any transplants. Soil is fed and protected through winter, and you don’t then need to spread new compost in spring, before new plantings.
Early plantings of dwarf beans finish by late summer, allowing time to grow brassicas for autumn and spring harvests, as well as salads, herbs and fennel. Soy beans may also finish by early autumn – then transplant brassica salads or spring cabbage.
Climbing beans need a whole summer to grow. Remove plants as soon as you have the final harvest, then transplant salads for harvest through winter and spring.
Another option, that goes against most rotation theory, is to transplant broad beans in late autumn. Or sow mustard as a cover crop/green manure.