This is a large family. There are over 17,000 species throughout the world. It includes many well-known vegetables such as broad beans, runner beans and peas, and some interesting plants like mimosa and cassia. There are also green manure and fodder crops such as clover or lucerne and lots of weeds – the vetches and trefoils. Some climb, some grow along the ground and some are trees.

Many legumes are what is known as ‘nitrogen fixers’ – that is, they take nitrogen from the air and store it in their root nodules. They therefore manage very well in poor soil. When they have finished flowering and producing fruits, this nitrogen is left in the ground and enriches it for others.

It is the seed pods that give this family its name. The pod may contain just one or several seeds, and they are usually large, and sometimes brightly coloured. The main vegetables that we grow usually have several seeds within the pod. The coat of the individual seed is often watertight. They usually germinate quickly given the right amount of water to penetrate the hard coating.

The familiar produce such as beans, peas and lentils are also known as pulses – from the Latin for bean porridge – and they have long been a staple food for humans. They can be eaten fresh from the pod, cooked in any number of ways and dried. Dried pulses make excellent nourishing soup. Where would we be on long cold winter nights without London Particular, split pea soup or bacon, tomato and lentil soup?

Legumes are packed full of protein and preserve very well – dried, frozen or made into soup and frozen.

Peas

Characteristics

Green fat pods hanging down symbolise these easy-to-grow vegetables. There are many varieties – early peas, late peas, mangetout, sugar-snaps. With these latter two you eat the pods as well (hence the name – from French meaning ‘eat everything’). They are reputed to be the oldest cultivated plants in the world. Seeds have been found in dwellings from the early bronze age.

Do not forget either their cousin the sweet pea – we grow it for its lovely flowers and rich fragrance.

By nature the pea is a climber and so it needs good support. You can, however, buy dwarf varieties that do not require a trellis or stakes, but we grow original climbing varieties. Most peas that are harvested and that we buy are frozen or canned, but taking a pod off the plant, breaking it open and eating the peas fresh cannot be beaten. They have a nutty flavour that is lost during the preserving process. One of the issues with gathering peas is that often more get eaten than harvested.

They do take up a lot of space relative to the harvest – but what sort of allotment doesn’t grow peas?

How to grow and when to plant

Peas can be planted outside from March. It is best if you have the space to sow them in batches every four weeks or so to provide several crops. We intended to do that in our first year – but forgot to put our second crop in. They like good rich moisture-retentive soil. They need plenty of water, as this is what makes the peas fat.

Germination is tricky. They need warmth to germinate and March weather can be unpredictable. A good trick is to sow them indoors and then plant them out. Carol Klein in her series Grow your Own Veg recommends using roof guttering and then sliding them into position when they have germinated.

You can use the root trainers that were developed for sweet peas and this allows good root growth as well. We just sow in situ.

Transplant them when they are about 4 inches (10 cm) tall and can be handled.

If sowing in situ, sow them about 2 inches (5 cm) deep, about 6 inches (15cm) apart, in two rows about 1 foot (30 cm) apart. Use crossed bamboo pole stakes for support, as with runner beans. This supports the plants and ensures that air circulates. If it turns cold after sowing in situ then cover the ground with fleece or cloches for extra heat.

Some recommend hoeing around the plants, but to be honest we didn’t and it didn’t matter very much (we pulled the weeds out though).

Dwarf peas are usually planted in blocks to give each other mutual support. You can also use pea sticks – which are just short sticks. Don’t forget to place something over the ends to save your eyes from being poked out!

Issues

• Mice love peas. So do birds and they will dig them up – although we didn’t have any trouble in our first year. Cover the pea seeds with spiky branches or cover in netting or fleece.
• Water is key – check every week for moisture. Mulching can help.
• Pea moth – see Pests.

Harvesting

Keep harvesting so that the plant continues to produce more. Take all pods that are ready – even if you are late with the picking – then you will get fresh ones developing.

If harvesting as mangetout, then you need to catch them just as the peas are visible in the pod. If you miss this (all too easy for busy people) just use them as normal peas (mangepeas as one of our friends called them).

After harvest, do not pull the plants up but cut them off at ground level. This leaves the roots in to fix the nitrogen for next season.

Storing isn’t really an issue as we eat all we produce – and so will you probably.

Runner beans

Characteristics

Another foreign plant that has been adopted everywhere, the runner bean is originally from Central America (Mexico) and used to warmer climes than chilly Britain. It was introduced by John Tradescant (of Tradescantia fame) in the seventeenth century and has become a firm favourite. It was originally cultivated for its beautiful flowers – until the beans were found to be edible in the eighteenth century.

Although they are perennials in their native lands, because the frost kills them in the UK we grow runner beans as annuals. They will produce a tuber (like potatoes) which would hibernate in the soil during the non-growing season in Mexico – but this isn’t really practicable in the UK due to the cold. They are very vigorous growers; often reaching 8 feet (2.4 m) or more. The crop is amazing and it keeps cropping until the first frosts. We had so many beans that at one stage we had to give them away and we only planted a relatively small area of the plot with them.

How to grow and when to plant

They are very, very easy to grow. They will grow anywhere, but heavy clay (like ours) will reap the benefits of having been dug over to aid drainage and having lots of organic manure dug in first.

Dig out two small trenches 2 inches (5 cm) deep and 2 feet (60 cm) apart. Construct a long bamboo cane pyramid (‘A’ frame) with 8 foot (2.4 m) tall canes, set about 8 inches (20 cm) apart on both sides and add a cross piece (or two). Anchor it very securely in the soil. Then sow two seeds at the bottom of every cane.

You can also create a wigwam by placing canes around a 1 yard (1 m) diameter circle about 6 inches (15 cm) apart and tying them at the top.

As the plants grow they will wind round the canes – but giving them a hand if they get a bit lost is a good idea, so tie them on gently. Watch out for convolvulus – it will also grow up the canes and strangle the beans given half a chance.

When the plants have reached the top of the cane, pinch out the shoots to encourage them to put their effort into flowers and beans.

3 sisters – or 2 1/2 really!

We sowed squashes, courgettes and pumpkins underneath the plants in the cool, and to suppress weeds. We had the main bean site with cucurbits underneath, and an experimental ‘3 sisters’ site with sweetcorn, beans and cucurbits. To be honest this gave us mixed success, as slugs ate the squashes – but not the weeds under the main bean crop.

On the other site the courgettes flourished under the sweetcorn, but the beans in that grouping didn’t. Later on the squirrels destroyed the sweet-corn – but we did get lots of tasty courgettes!

Issues

• Runner beans need plenty of water, so do not let them dry out. Water makes the beans fat! In really hot times, a mulch can help. We used straw, which also helps keep slugs away from the cucurbits.
• Aphids are a nuisance, but let the ladybirds take care of them. Or you can spray the plants with dilute soap solution.

Harvesting

Pick as soon as the beans are ready (about 6 inches or 15 cm long) and keep picking. They will keep producing. Do not let them get too long or they go hard and nasty – like they used to be at school!

Take off all long, old pods to encourage the development of young, tender, new ones. When we find tough pods, we open them, take out the beans for next year, then compost the hard skins.

If you take the beans off a little late and they have started to go a bit tough, use a potato peeler to take off the nasty edges on both sides.

Note that some people suffer a rash from the hairs on the plant. If you do, wear gloves and long sleeves when harvesting.

French beans

Characteristics

These are very similar to runner beans. They were brought to Britain by the Huguenots, who were French Protestants betrayed and expelled by Louis XVI. They are smaller than runner beans, and for some people have a better flavour. The plants grow in the same manner to runner beans, being vigorous climbers. They can be harvested when young and eaten whole, or left to turn into flageolet beans and ultimately into haricot beans. In China, as a result of this they are called sandomame – the ‘three times bean’. They are also called string beans, Kenyan beans, Borlotti beans (popular in Italy) or kidney beans.

They come in several colours – red, blue, yellow, striped and the more familiar green. Next year we are going to go for blue and yellow to brighten up dinner times. There are two types – climbing and dwarf or bush – with the difference self-evident. Climbers tend to be less prone to disease as the air can circulate better, but dwarf plants are usually 18 inches (45 cm) tall and easier to grow under cover. This is important if your site is cold for much of the year – as French beans love warmth (being originally from Central and South America).

Climbers give a better yield and crop continuously, whereas dwarves mature all at once over a short period, so it is best to succession sow dwarf varieties over a few weeks to ensure a constant supply.

How to grow and when to plant

French beans need a warm sunny site that is sheltered. For that reason it may be easier for you to grow runner beans depending on your circumstances. They also like very rich soil, so it is best to dig out a trench and fill it with organic matter before sowing.

If your site is cold and/or exposed to wind and driving rain, go for dwarf varieties which you can protect more easily. They like a pH of around 7.0.

Sow in situ when the temperature has warmed up – late May onwards; although you can grow the climbers under cover and transplant them out in summer. Warm the soil up for them by covering it before sowing or transplanting. Harden the plantlets off first before placing them in their final site.

For sowing in situ, plant the beans 2 inches (5 cm) deep, about 8 inches (20 cm) apart in rows. They are tricky to germinate so expect around 25 per cent losses. You can always plant a few extra elsewhere to plug gaps. Place climbers in rows 2 feet (60 cm) apart and give them stout support with canes as for runner beans. They will grow up to 8 feet (2.4 m) like runner beans. You can also train them up arches, wigwams and along fences. Their flowers are very pretty as well.

With dwarf varieties, earth them up to the bottom layer of leaves for extra support.

Issues

• Cold will kill French beans. If there is a sudden cold snap then you must cover them up.
• Birds, slugs and mice (the usual suspects) will also eat young seedlings, so protection is a good idea.
• Wind and hard rain will damage them, so ensure that they are sheltered.
• A mulch is a very good idea as they need lots of water – but only after the flowers have appeared or you will get too many leaves.
• Aphids of course are a problem.

Harvesting

Keep picking and they will keep producing. They should snap easily and not be stringy.

To get haricot beans, leave them on the plant for a few weeks longer. Harvest the dwarf varieties in the order that you sowed them.

Climbers will crop for the whole summer. If you can see the beans bulging out then they have passed the French bean stage and are well on their way to becoming haricots.

Flageolets sit in between these stages when the beans are quite small – tricky to spot!

Broad beans

Characteristics

This was our first successful crop. We had lashings of beans which went down very well. We then left the roots in to fix the nitrogen. The beans are found in pods wrapped in a lovely velvety blanket to keep them nice and warm. They like cool conditions so are perfect for our climate.

If you are starting out on your allotment, then broad beans are a must to grow – they are so easy you can virtually guarantee success. Don’t worry if you think that you don’t like broad beans – I never did until we grew them. Cooked properly they are wonderful. We are going to grow a lot more next year.

Broad beans are one of the oldest-known crops – being mentioned in the Bible and having been found from Neolithic times! Before potatoes they were one of the staple crops for humans in Britain and elsewhere and until relatively recently were the most widely grown bean in the country. In Ancient Rome they were used for voting in the Senate – black meant non (no) the whiter beans ita vero (yes). Interestingly, the Spanish ‘swapped’ broad beans, for runner beans, introducing them to South and Central America.

How to grow and when to plant

One of the curious things about broad beans is that successive sowings often catch up with earlier sowings – even if months apart. They like heavy soil so are perfect for our allotment – but will grow anywhere, being hardy. If possible the soil should be pH neutral.

Dig in plenty of organic matter before sowing. They have very large beans that are easy to plant directly into the soil. Sow them in rows 18 inches (45 cm) apart, 2 inches (5 cm) deep, with 6 inches (15 cm) between seeds in late March or April. You can also plant a crop in October for early cropping next year. They reach maturity in about 2 ½ months. Support the plants with stakes and string. Winter sowings do not need organic matter dug in. Broad beans ideally like sunny sheltered spots, but are hardy and can be grown anywhere.

Issues

• Aphids (blackfly) are attracted to broad beans. Pinching out the growing tips after the pods start to appear can help avoid this.
• Pigeons and mice will try to eat the seeds or seedlings, so protect them with sharp pointy things laid over the seeds, or netting when they are a little larger.
• The pods get heavy and can break the stems, so ensure that the support is adequate. We use the same arrangement as for runner beans.
• Once the beans are growing, water well. Mulching also helps.
• Spots on the leaves – ‘Chocolate spot’ can occur if it is very wet and humid early on and ‘Rust’ may appear if it is dry. They are not usually very serious.

Harvesting

Broad beans are the first bean to mature and if you sowed over winter you can start picking them in June. Pick the bottom beans first as they are the most mature, but don’t let any get too big. Gently twist them off or use secateurs.

Once you have finished harvesting, do not pull the plants up. Cut them down and leave the roots to set nitrogen. Compost the rest.

For storing, you can dry them, or blanche them and freeze them.

Clover

This is only really grown as a green manure. It is a nitrogen fixer and puts back goodness into the soil (see Green Manures). Sow after you have harvested a crop and leave to over-winter then dig in in early spring.

It grows very fast and you can also eat the young shoots in salads.