The leaves, stems, roots and flowers of plants have been eaten uncooked or part cooked since well before cereal-based agriculture came to the croplands thousands of years ago. Many of what we now call vegetable crops were brought here much later than the cereals, some such as turnip and potato within the last few hundred years. Others, including sweet corn and sunflower arrived even more recently from sub-tropical lands. The garden vegetables are a highly diverse group of plants, each providing one or more plant parts for harvest – leaf or stem stem, young flower, root or tuber, seed pod and seed itself.
The quality of each vegetable is influenced by the part it plays in the plant. The leafy ones such as spinach, lettuce and rocket are high in nutrients and trace elements, a necessity of their role in capturing and converting sunlight. The legumes, peas and beans, are high in protein, especially in their pods and seeds, a result of the unique ability of these vegetable plants to fix nitrogen from the air (see the page on Legumes).
‘Roots’ such as turnip, swede, potato, beet and parsnip are storage organs, rich in carbohydrate. The ‘roots’ changed food security in these islands for the better when they were introduced as field crops after 1700. They provided living plant food for people and their stock animals through the winter, long after the cereals and grain legumes had been harvested.
Brassica – leaf, flower and root
The cabbage family has contributed more than any other, except perhaps the legumes, to the variety of the vegetable garden. At its centre is the wild cabbage Brassica oleracea a species that has given rise to an array of domesticated sproutings and sprouts, cauliflowers and leaf cabbages. Its close relative Brassica rapa is widely known as the turnip, a swollen stem tuber, and a yellow flowering oilseed crop grown in parts of northern Europe. Their hybrid Brassica napus also divides into tuber and oilseed forms – the yellow-orange fleshed swede (neeps) and the crop now widely grown here and known as oilseed rape. Most forms of cultivated brassica can be eaten raw as seedlings.
Peas and Beans
The small nodules, usually about 2 mm wide, on the upper roots are the sites of nitrogen fixation by these legumes. Most soils already contain the bacteria that will invade the roots and form the symbiosis that creates the nodules. The fixed nitrogen is moved around the plant, being concentrated in the pods and seeds, which are thereby high in nitrogen and protein. The legumes grown in our climate are mainly from the plant genera Vicia, Pisum and Phaseolus. The broad bean Vicia faba is the same species as the commercially cultivated field bean. Species of Phaseolus make up most of the rest of the beans, now available to the gardener in many forms and certified varieties. Peas, most forms of Pisum sativum, are variously suitable for eating as whole pods or unripe pea seeds, and in marrowfat varieties, can be dried and stored for many months.
Beetroot and chard
Beet is one of the Chenopodium family, so a relative of the weed and one-time vegetable fat-hen, spinach and the glassworts (Salicornia). Beet consists of a wild form that has given rise to many cultivated forms – sugar beet, fodder beet, the leafy chards and the well known red ‘root’ varieties that are commonly referred to as beetroot. Like wild cabbage, wild beet has a very restricted range close to the sea. Some taxonomies name all these beets as Beta vulgaris defined by a subspecies e.g. ssp. maritima for wild beet and ssp. vulgaris for root beet. Most forms are are sexually compatible and hybridise. The cultivated forms are mostly biennial, vegetative in the first year then flowering the next, but occasionally ‘annual’ genes find their way into cultivated seed.
Carrot and parsnip
Both carrot Daucus carota and parsnip Pastinaca sativa are members of the umbel-bearing family, now called Apiaceae, that have swollen upper roots in their cultivated forms and sometimes in the wild. The wild and cultivated forms are usually distinguished as sub-species. Both species tend to be biennial, producing the swollen root in the first year and flowering in the second. Wild carrot grows freely in the garden, self-seeding and establishing itself where the ground is undisturbed for a few years. Wild parsnip has a more restricted distribution; presently, there are no examples in the garden.
Maize and rice
The sweetcorn varieties of Zea mays will grow here in a warm summer. This year they produced fine small cobs, tasty roasted or grilled with herbs and oil. Maize is a grass family member that holds its male and female organs at different points on a plant, not in the same floral structure. We tried rice once but it came to little.
The cold and wet usually sees off anything mediterranean or subtropical but this year, apart from well grown sweet corn, pumpkins have produced good fruit and sunflowers are filling their seed heads. A water melon plant lasted for a time then faded.
Sources and management
Potato varieties are grown every year in one of the four crop beds as part of the arable sequence. In some years the whole of another crop bed is grown with the cabbage family, including turnip and swede. In other years, there is a mix of legumes and
Potato varieties usually come from the Institute’s collections. Peas, beans and the leaf vegetables are from standard suppliers. Staff at the Institute sometimes donate specialities – this year we had giant sunflower, sweet corn, two types of pumpkin and a water melon from a member of the horticulture staff, Jim Wilde.
Our vegetables generally grow well but can suffer the same disasters as many gardeners experience – gaps in rows where seeds fail to germinate, weeds, disease and predation. Small weed infestations are left to be out-competed by the crops, or removed by hand if they look like they will get too dense. Potato is usually sprayed against disease. In most years insect pests are not a big problem, perhaps because we encourage parasitic wasps, spiders, ground beetles and their other natural enemies by ensuring habitat for them close by.
One thing is certain, as every gardener will tell you – fresh vegetables, picked, cooked and eaten the same day are so delicious they make you realise how bland is the usual packaged fare.