Purple haze: Aubergines taste great on a summer barbecue but the time for planting is now

If the weather is kind, if the soil has dried out a little, if the night temperatures aren't plummeting too low, if, if, if. For a gardener itching to get on with sowing vegetables, April is full of ifs. TS Eliot wrote of it "stirring dull roots with spring rain" but it's not rain we need so much as warmth. Anyway, if the signs seem propitious this month, you should be able to sow asparagus peas, beetroot, the broad beans you didn't sow last month, carrots, chicory (the kind you blanch), chrysanthemum greens, corn salad, spring onions, endive, kohl rabi, land cress, leeks, lettuce, parsley, parsnip, peas, rocket, salsify or scorzonera, summer spinach, turnips and a whole clutch of cut-and-come-again seedlings. On a windowsill or under cover, you might try seed of different kinds of tomato.

If you've got a greenhouse, then you might be thinking of cucumbers and aubergines, sweet peppers and chilli peppers. All these can be grown in pots or Growbags, but for the next couple of months at least, need to be kept under cover. Aubergines have a long growing season (at least five months) which is why seed is generally sown in March. But if you move quickly it may still be worth doing, using a variety such as 'Moneymaker F1' (Suffolk Herbs £1.50), a very prolific variety that starts producing fruits more quickly than some other types. There'll be at least 40 seeds in the packet, far more than you need, but the viability is good and they should last up to six years if they're stored in a cool, dry place.

If you want to get ahead of the game, you can order young plants instead of sowing seed. Delfland are offering 'Ophelia' for delivery this month. It makes a neat, compact bush and bears smallish fruit, but lots of them. Three plants cost £1.70 with postage and packing extra.

If you are sowing seed, use cells or small pots, setting a couple of seeds in each. Cover them, press down the compost lightly and stand the pots or cell trays in water until the surface of the compost has darkened in colour. This will tell you that the water has soaked through to the level at which the seed sits. If both seeds germinate, pull up one of them.

If you have sown in cells, you will need to pot on the plants before they move to the place where they will finally grow. If you have sown in 8cm pots, you may be able to keep the plant pushing on until you set it out in a Grobag or plant it in its final container. This should be a big one, 25cm or 5 litres at least. At this early stage, aubergines need plenty of light and a minimum temperature of about 15C. By midsummer, your plants will be expecting a night temperature of at least 16-19C.

You'll get better plants if you can get them into the ground, either in a greenhouse or polytunnel. Cold frames work too, if they rise far enough off the ground. Otherwise the plant, as it grows, bangs against the roof. On an allotment, you can build a makeshift cold frame to shelter aubergines and pepper plants, using straw bales (excellent for insulation) or polythene (not so good) with a roof made from an old window or clear plastic stretched on wood batons. Glass lets in more light than plastic and with aubergines, good light is important. They fruit far less well in dull, overcast summers than they do in bright ones.

The trick with plants such as aubergine (and chilli peppers) is to keep them growing on steadily without check. Aubergines need plenty of water to drink and like a warm, damp atmosphere in which to grow. Misting round the plants helps. So does damping down the floor of a greenhouse or polytunnel. Dampness is your best defence against red spider, which is one of the pests drawn to aubergines. The other is whitefly. If you believe that companion planting works, try setting basil plants next door to your aubergines. If you don't, invest in a hand-held car vacuum and hoover up the whitefly on the wing. If you shake the plant, they take off in clouds. Introduced predators, such as Encarsia formosa, only work well in enclosed spaces such as greenhouses and polytunnels.

Misting also helps fruit to set and you will get more fruit if you pinch out the growing tops of your young plants when they are about 20cm tall. From a variety such as 'Moneymaker F1' you might get six aubergines per plant. 'Ophelia' will give you smaller fruits but more of them, perhaps a dozen. Don't expect the vast fruit that you see in the supermarket chiller cabinet. You can pick them when they get to 8cm or longer.

In containers, the plants will need feeding, a high nitrogen feed for a short time at the beginning of their growth, to encourage plenty of lateral shoots. Later you should switch to a feed such as Tomorite, with plenty of potassium, which encourages the development of fruit.

I used to wonder why aubergines were called egg plants, having never seen the smooth white-skinned varieties such as 'Snowy' (Suffolk Herbs £1.30) that you see in India. India is the aubergine's home and it wandered from southeast Asia westwards with the Moors who eventually brought it into southern Europe. But that's why it needs heat to be happy, much more heat than chilli peppers, which tend to be grown in much the same way.

In India, too, you'll find tiny, whole green aubergines used in vegetable curries. We don't often see them over here (recipes substitute peas instead) but if you want to try the authentic thing, sow seed of 'Thai Green Pea' (Chiltern £2.54). They are excellent in stir fries, as well as curries.

Cookery books still tell you that slicing and salting aubergine before you cook it gets rid of any residual bitterness, but modern varieties aren't bitter. The seed breeders have seen to that. Salting slices (and patting them dry after you have washed the salt off) may possibly reduce the amount of oil they take up if you fry them. But I think they are best grilled, when they need very little oil at all. They are excellent barbecued, or steamed, skinned and mushed into a dip with lemon juice, garlic, olive oil, salt and pepper. Using sesame oil and roasted sesame seeds in the mix gives a different flavour.

Suffolk Herbs, Monks Farm, Coggeshall Rd, Kelvedon, Essex CO5 9PG, 01376 572456, suffolkherbs.com; Delfland Nurseries Ltd, Benwick Rd, Doddington, March, Cambs PE15 0TU, 01354 740553, organicplants.co.uk; Chiltern Seeds, Bortree Stile, Ulverston, Cumbria LA12 7PB, 01229 581137, chilternseeds.co.uk

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