Vegetables

Buying in season

There's been an explosion of variety and year-round availability of vegetables. So why choose local produce in peak season? Taste for starters - food harvested in its natural season and environment has a depth of flavour that surpasses anything that's travelled far or been grown out of season. The price of mid-season vegetables is lower too - particularly if bought at your local street market. Seasonal foods also tend to suit the mood; roasted root vegetables are comforting in winter and herby salads perfect in summer.

Less obvious are hidden costs such as food miles. The average supermarket product has travelled 1,000 miles. Purchasing locally grown, in-season vegetables greatly reduces the environmental cost, and helps support local producers. What's more, by knowing where our food comes from we gain a sense of control over what we choose to eat.

For more information, read our food miles article.

Buying organic

Washing vegetables thoroughly and peeling may help remove residues of certain pesticides. Nevertheless, other pesticides are systemic (found within the vegetable). Artificial fertilisers and pesticides are banned from organic agriculture, so organic farmers use traditional methods such as crop rotation and natural fertilisers.

Organic food is generally more expensive then non-organic produce and the majority of organic produce sold in Britain is imported, adding to the environmental impact of 'food miles'. So make sure you know what you're buying and buy local organic wherever possible.

The bigger supermarkets have specific organic sections; most stock prepared salads, speciality vegetables and frozen organic vegetables, as well as the basics. Many specialist organic shops and health-food shops sell fresh organic produce, and hundreds of smaller British growers sell direct through box schemes and farmers' markets. Contact the Soil Association for details of your nearest scheme. When buying organic, look for the logo of the Soil Association or other certifying bodies.

For more information, read our article on organic food.

Visit the Soil Association's website.

Vegetable varieties

Vegetables can be broken down into the following groups:

Bulbs: garlic, leeks, onions (brown onions, button onions, pickling onions, red onions, Spanish onions, white onions), shallots, spring onions

Fungi: mushrooms such as button, chestnut, flat, oyster, porcini, shiitake

Leafy greens and brassicas: broccoli, Brussels sprouts, cabbage, callaloo, cauliflower, chard, kale, pak choi, spinach

Pods and seeds: broad beans, French beans, okra, peas, sweetcorn

Roots and tubers: beetroot, carrots, cassava, celeriac, horseradish, Jerusalem artichokes, kohlrabi, mooli, parsnips, potatoes, radish, salsify, sweet potatoes, turnips, water chestnuts, yams

Squashes: courgettes, cucumbers, gourds, marrows, pumpkins, squashes

Stalks and shoots: asparagus, cardoon, celery, globe artichokes, fennel

Vegetable fruits: aubergine, avocado, breadfruit, chillies, plantain, peppers, tomatoes

Tips on buying

Choose vegetables in season, when they're at their freshest, tastiest and most nutritious. Look for crisp vegetables with brightly coloured leaves. Go for firm skins and unblemished flesh (but remember, organic produce often doesn't look pristine). Avoid vegetables with brown patches, wilted or slimy leaves, bruised or pulpy flesh. But don't be put off by odd-shaped fruits - sometimes these can be the tastiest.

Bulbs: choose firm bulbs with even-coloured skins and no signs of sprouting; avoid any that look damp or smell musty; onions should have dry papery skins, red onions should have no brown discoloration; leeks and spring onions should have dark-green leaves and fresh-looking roots.

Fungi: choose firm, fresh-looking mushrooms with no sign of sweating or damp smell; the stalk end should be moist.

Leafy greens and brassicas: choose endive, Swiss chard and spinach with crisp, fresh-looking leaves that are springy to the touch; there should be no sign of insect damage; cauliflower, broccoli, Brussels sprouts and cabbage should have tight compact heads and no sign of wilting; the stalk should look moist and freshly cut.

Pods and seeds: select peas and beans with bright green pods that are firm and plump; choose sweetcorn with tight green husks and plump, shiny kernels tightly packed on the cob.

Roots and tubers: carrots, potatoes, beetroot, swedes, celeriac and radishes should have firm, heavy flesh and wrinkle-free skin; avoid any with soft patches or sprouting; carrots should have fresh-looking, leafy tops, with no discolouration or wilting; potatoes should be firm and well-shaped with no eyes or green patches.

Stalks and shoots: celery, globe artichokes, fennel, asparagus and chicory should have tightly packed, firm heads with no brown patches on the outer layers.

Vegetable fruits: tomatoes, aubergines and peppers should have firm, smooth, shiny skins and a deep, even colour; avoid any that are pulpy or wrinkled. Avocados, when ripe, should give slightly if gently pressed.

Storing and freezing vegetables

Most salad vegetables will keep for a week in the salad drawer of the fridge, but tomatoes shouldn't be kept in the fridge or their texture will suffer. Root vegetables and squashes will keep for a week or two in a vegetable rack in a cold, dark place but can keep for many weeks if stored properly. Keep strong-smelling vegetables such as onions and leeks away from other foods. Remove tightly wrapped packaging and store the vegetables loose. Store cut vegetables in the fridge.

To store fresh beetroot, cut off the leafy tops and then place to dry in a single layer in a wooden or cardboard box. Potatoes can be stored in hessian or paper sacks; just remove any moist mud from them to prevent mould from forming. Store in a cool, airy, dark place, such as a larder or a shed.

Onions, garlic and shallots can also be stored. Plait the leafy tops and then hang them up to dry in a shed, larder or another airy, dry place.

Freezing doesn't preserve food indefinitely, but frozen vegetables will keep for up to six months. For best results, arrange the prepared vegetables on a large tray and freeze for a few hours until solid. Transfer to a freezer bag - extract as much air as you can using a straw, tie securely and label. Alternatively, pre-cook your vegetables before freezing. Prepare as if you were going to eat it straightaway then blanch quickly for 1-2 minutes in boiling salted water - this stops enzyme activity - but take care not to overcook. Refresh for a few seconds under running cold water, then leave to go completely cold. Bag, seal and label as above. This method works particularly well for French beans, broad beans, peas and broccoli.

Preparing vegetables

Vegetables are extremely versatile; most can be eaten raw (as crudites served with dips, or grated into salads), and they can be cooked by virtually every method.

All vegetables should be washed thoroughly before use, to remove dirt and traces of pesticides if they aren't organic. Peeling vegetables is an easy way to remove surface dirt or germs, but don't peel too thickly because many nutrients are stored just below the skin. It's not necessary to peel at all if they're organic (unless your recipe calls for peeled vegetables).

There are safe levels of pesticides to which producers must adhere, but tests sometimes find levels exceeding them. The Food Standards Agency advises that washing vegetables thoroughly and peeling may help remove residues of certain pesticides. Nevertheless, other pesticides are systemic (found within the vegetable).

Steaming and boiling

Steaming vegetables over boiling water (or other liquid such as wine) is a healthy way of preparing them, because the loss of vitamins is significantly reduced. Steaming also preserves texture and flavour. Cut vegetables into even sizes and flavour the steaming liquid with herbs or spices, if you like, which will mildly infuse the vegetables.

Most vegetables can be boiled, in water or other liquid, but some vegetables such as aubergines, tomatoes or peppers are much tastier fried, roasted or grilled. Cook green vegetables in already boiling, salted water without a lid. For most root vegetables start them in cold water and bring to the boil with a lid on. For leafy greens and brassicas add them to already boiling water and cook without a lid.

How long you cook vegetables for is really down to personal taste - but bear in mind that the longer you cook them the more nutrients will be lost. Nowadays most people prefer to cook vegetables lightly, leaving them brightly coloured with a little 'bite'. As a general guide, most leaf greens, brassicas, pods and seeds and stalks and shoots will take about five minutes to boil, about twice as long to steam. Roots, tubers and squashes (but not courgettes, which cook very quickly) will normally take 10-20 minutes to boil, depending on their size, and slightly longer to steam.

Check to see if vegetables are done by piercing them with a knife or tasting them. Drain them and serve at once. If you want to serve them later, plunge them into cold water to stop them from cooking further then cook again very briefly in boiling water when you're ready to serve.

Other methods of cooking

'Soft' vegetables such as onions, greens, beans and mushrooms are delicious simply fried in butter or oil or stir-fried to keep them crunchy and flavoursome.

Oven-baking allows you to cook vegetables for a long time at low temperatures. It's good for concentrating the sugars of vegetables such as onions, beetroot or squashes. Root vegetables and summer vegetables all roast well - just cut into chunks and toss in olive oil and herbs in a large roasting tray. Bake them at 180C/360F/Gas 4 until tender and beginning to tinge brownish-black at the edges.

Vegetables are delicious when grilled with a little oil and seasoning, particularly aubergines, peppers and courgettes. Grilled vegetables retain their flavour without becoming too oily.

Root vegetables and squashes are well suited to pureeing. Cook them first by boiling, steaming, baking or even grilling, then mash to a purée. Other ingredients such as cream, butter, milk, herbs and spices can be added, either to thicken or thin the purée, and add flavour.

Many vegetables are perfect for stuffing - particularly aubergines, courgettes, tomatoes, squashes and jacket potatoes. Cabbage leaves or courgette flowers are ideal for holding stuffing. There's endless scope for fillings - from rice, couscous and other grains, to cheese, herbs, minced meat, mushrooms and other vegetables.

Because of their natural sweetness many vegetables are used in desserts, for example carrot cake and pumpkin pie.

Recipes

Grilled vegetables with pitta croûtons by Paul Merrett (video recipe)

Mixed vegetable curry by Madhur Jaffrey (video recipe)

Country vegetable soup with basil pistou by Mike Robinson (video recipe)

Butternut squash and pumpkin pie by Simon Rimmer