Sweet basil is best treated as an annual so you need to grow fresh plants from seed every year. However, it's worth taking the trouble for a regular supply of the delicious aromatic leaves. The usual sweet basil grows to 30-60cm tall and about 30cm wide and has bright green, aromatic leaves. If not picked over regularly, it will produce clusters of small white flowers in summer. Like the mints, basil also comes in a range of different forms. Some have interestingly coloured and shaped leaves. The darker green "Genovese" basil is widely regarded as the best for pesto and garlic-flavoured dishes. "Dark Opal" has rich purple leaves and pink flowers. The aptly-named cultivar "Purple Ruffles" produces extravagant, frilly purple leaves and the lettuce leaf basil (Ocimum basilicum "Napolitano") has large, crinkled leaves.

There are also basils with all sorts of interesting flavours - for something different, you might try the spicy-scented leaves of cinnamon basil or the lime-fragrant leaves of lime basil (Ocimum americanum). Other varieties include aniseed-scented Thai basil (Ocimum basilicum "Horapha") that's essential in Thai cooking or Mrs Burns' basil with its intensely lemon-scented leaves. Bush basil (Ocimum minimum) is smaller at 30cm tall and is excellent for growing in pots as is its close relative Greek Basil (Ocimum minimum "Greek").

Planting
Sow seed at 13°C (55°F) in early spring or sow directly into a border in the garden in early summer. However, even if you do want to grow them in the garden, you will probably get better results by starting them off in pots of compost and planting them out as young plants once the frosts are over (usually the start of May is fairly safe but check with a knowledgeable local!). The ready-grown basil plants that can be picked up in the supermarket have been raised in an artificial environment and always seem to die rather rapidly. Growing your own from seed is far more likely to produce a longer-lived, tougher plant that can adapt to the environment you are going to give it!

Soil and position
Grow outdoors in fertile, well-drained soil in a sheltered site in full sun. They also do very well indoors in pots on a sunny window sill or are handy in a pot in sunny spot by the kitchen door.

Care
water freely during dry periods but do not let the soil become waterlogged. To ensure continued leaf growth, pinch out flower-heads as soon as they appear. Basils may be attacked by aphids, remove these by hand or spray them off with water.