Peas and beans
Peas and beans are both members of the same family, Leguminosae. Legumes have an association with a particular family of bacteria, called rhizobia that convert nitrogen from the air into protein. The process is called nitrogen fixation. Each species of pea or bean has its own species of rhizobium that must be present for nitrogen fixation to occur. If you are gardening where peas or beans have ever grown before, you will need to introduce the beneficial bacteria. All the backyarder needs to do is obtain a little soil from a garden that has and sprinkle it about your garden. Till the soil to allow the bacteria to go to work on your future crops. The market gardener will find it more economical to inoculate the seed with bacteria purchased from a rural store that supplies seed to farmers.
French beans and garden peas do not have a long enough life span to produce very much in the way of nitrogen. The Fava bean, (broad or tick bean) contributes considerable quantities of nitrogen and is worth growing on this count alone. Fava beans grow best in cooler weather and are generally sown in late autumn to late winter. Cowpeas are also grown over the winter for the purpose of nitrogen fixation, but they contribute somewhat less nitrogen and organic matter. When grown as a green manure to be tilled into the soil in spring, they are often sown with a cereal, such as oats, rye corn or barley.
Nitrogen fixation will not occur without sufficient molybdenum in the soil. This element is required for the formation of a critical enzyme. Its availability is dramatically decreased in soil that is too acid and often liming is all that is required. If there is still insufficient molybdenum, it can be supplied as a soluble salt (sodium molybdate) as a foliar spray. Seaweed contains a certain amount of molybdenum, and so can be used to supply a minor shortfall, either in the compost, as a foliar spray, or applied to the growing area.
The major difference between peas and beans is that peas have a hollow stem and beans have a solid stem. There are dwarf and climbing members of both tribes. The taller varieties require support in the form of wires or trellises, if they are to produce the much heavier crops of which they are capable. Beans climb by twining around their support. Peas have little tendrils on the stem that do the twining. Poles or vertical strings make the better support for beans and horizontal strings are better for peas.
The taller sorts crop over a much longer time than the dwarfs, as well as producing a heavier crop. It would appear that the breeding of dwarf varieties for harvesting convenience was at the expense of flavour. Harvesting convenience is also a moving target. While the dwarfs make for more efficient mechanical harvesting, trellised plants require much less painful bending of the back than dwarfs. This largely offsets the inconvenience and expense of trellising.
Both peas and beans are classed as light feeders. They rarely need any more compost than the remnants left in the soil by the previous crop. Where the soil continually becomes more acid, the pea and bean break is used to lime the soil. Peas and beans are quite tolerant of fresh lime and need plenty of calcium.
Dwarf beans need no support apart from being sown in double rows so that they support each other. Short peas that grow to less than a metre in height are often happy with just a few sticks placed here and there. Some gardeners use bits of wire netting. The taller peas and beans need a proper support, as shown in the illustration. We tried Jeavons method of sowing peas all across the bed in a thick swathe. While yields are high, the peas are very hard to harvest. A well-supported narrow row of peas is readily harvested and the unused strip of bed can be sown to root crop, such as beetroot.
At Eliot Coleman's suggestion, we use monofilament fish netting as the support, rather than wires, or strings. It is very inexpensive and the supplier told me that it lasts about seven years in full sun. As we remove the fish net at the end of the season and put it into a compost heap to remove the crop trash, we expect the netting to last a very long time indeed.
Peas are sown 30-40 mm deep and very thickly, either in long narrow rows, or double rows with about 750 mm between rows and 75 mm between seeds or in a continuous swathe across a raised bed with 75-100 mm between plants. The lower pods tend to rot on peas left to trail across the ground. There is only one pea available that grows very tall and it is referred to as a Telephone pea. The variety is Alderman and dates back to the last century at least. It grows to 2 metres tall and has large peas in large pods. The peas swell more slowly than other varieties, so picking requires more care than the usual varieties if you want filled pods.
The main varieties grown these days reach to 450-1500 mm in height. The most popular is Greenfeast, a tasty pea that is a heavy cropper growing to well over a metre in height. Melbourne Market (William Massey), is a short, winter-hardy variety and the pods are much larger than Greenfeast. Onward is similar to Greenfeast, but crops a week, or two earlier.
In recent years, the Snow Pea has become very popular because you can eat the pods without shelling out the peas while they are still flat and immature.
A quite recent introduction is the Sugar Snap pea that is allowed to fill out before eating pods and all. These were said to be the result of an intensive breeding program in the US, but we have an heirloom variety called Molly's Pea. Molly's Pea is very winter hardy and a very early cropper.
Garden peas are eaten by shelling out the peas somewhat before full maturity, before the sugar is turned to starch. Over-mature peas have prominent veins on the pods.
French beans are of two sorts, dwarf and climbing. Blue Lake, one of the climbing sorts, has the flavour to which all other beans are compared. It is a "stringless" bean and they require a warmer climate than the so-called "string" beans. When conditions are too cool, the pods of beans become curved and remain small. String beans are more tolerant of cool weather, though if they are picked at the right stage of maturity, before they develop strings, are just as tender. String beans have flattened pods, stringless cylindrical pods.
Climbing beans are sown 25-50 mm deep in rows one metre apart and 200 mm between plants. Dwarf beans are sown in double rows with 450 mm between rows and 100 mm between plants. The double rows allow the plants to give each other some support, as they are prone to wind damage. When sown in swathes across wide beds, they are sown about 150 mm apart each way. This makes harvest more difficult, but yields are somewhat higher.
French beans come in a variety of colours. Butter beans are yellow, and there are streaky red, purple and green sorts. Purple beans turn green when cooked.
Runner beans are perennial and were introduced from America along with the potato, and tobacco. They form a starchy tuber under the ground and this is reputed to be edible though we have never tried to eat any yet. Each spring, the tuber shoots produce a number of stems that form brilliant scarlet flowers. There is a rarer white flowered strain and a dwarf variety is available in the UK.
For many years runner beans were grown in Europe only for the display they made. The beans have a reputation for being stringy and tough, but gourmets are aware that when picked young and tender, they have a unique and superb flavour. Runner beans are very prolific and a few plants only are needed for the average family. The sowing requirements are the same as for the climbing French beans.
Some gardeners lift the tubers and store them in sand over the winter. The tubers are planted out in spring and this is supposed to give an earlier start. They tolerate cooler weather than French beans and dislike very hot conditions. We grow both sorts in the knowledge that no matter the season, one, or the other is going to do well. Sometimes pod-set is a problem and a misting of cold water in mid-morning helps.
Some French bean varieties are grown to dry for use in winter soups and so on. Cannelini are white, Red Kidney brown and Borlotti are speckled. Cannelini and Red Kidney are dwarfs and Borlotti is a climber. The pods are left on the bush to dry, before being shelled out and stored. They perform poorly in cool, humid conditions, as they are prone to a disease called halo blight. This complaint is a seed-borne disease and so prevents saving any French bean seed under such conditions.
Soya beans are also difficult to grow in cool districts, though Fiskby IV is a variety more tolerant of cool weather than others. In southern Tasmania, I was disappointed by the yield. The seed is also very small.
Broad beans were the staple diet of the ancient Egyptians and Europeans through the Middle Ages. Their strong flavour is disliked by some, but there is no other cool climate bean to rival their yield and versatility. We eat them as immature beans as if they were French beans, pods and all. Later, we eat the tender, immature beans. After they become starchy, we slip the skins off the cooked beans to eat the green inner portion. This makes a particularly fine soup. Finally, some are left to dry, both for seed and for winter soups.
Unlike French and runners, they are somewhat self-supporting as they have stout stems. They are prone to wind damage and so are often sown in double rows for extra support. This is all Coles Dwarf need, but stakes and strings are generally necessary with the taller varieties. They are sown 50-75 mm deep 150 mm apart in rows 600 mm apart. Autumn and early winter are the best sowing times in most districts and late winter second best. Grown too early, they will be buffeted by strong winds, too late and they are prone to attack by aphis. At the onset of aphis attack, removal of the the growing tips prevents further damage as the aphis only attack new growth. These tips make a lovely substitute for spinach.
Broad beans and their close relatives, the tick beans, are often grown as a green manure. Since they are a long season crop, they fix copious quantities of nitrogen for use by subsequent crops. They are also very bulky, providing copious quantities of organic matter to feed the soil microorganisms.
Coles Dwarf is shorter than the other varieties and so is less prone to wind damage. Green Windsor is reputed to have the best flavour, but the seed is difficult to find (we save our own). Aquadulce Claudia is very early. One of our favourites is Big Ben, which is a prolific cropper. The productive period is quite short compared to others, so a succession is necessary for prolonged production.