🌿 Basil

Basil is the great summer herb, sweet, peppery and fragrant, and it belongs next to the tomatoes. It needs warmth, so it is best grown on a sunny windowsill, in a greenhouse or in a sheltered, sunny spot outdoors after the last frost.

Beyond the classic Genovese, there are Thai, lemon, cinnamon, purple and tiny-leaved Greek basils, each with a distinct flavour. Pots are ideal, and sowing a little every few weeks gives plants through to autumn.

Varieties to try

Genovese (classic for pesto)Greek (small leaves, neat and compact)Thai (aniseed flavour, for curries)Lemon (citrus aroma)Purple ruffles (ornamental, mild)Lettuce leaf (very large leaves)

Sow on the surface of moist seed compost from April to July, 5 mm deep, at 18–21°C on a bright windowsill. Seed germinates in 1–2 weeks. Prick out seedlings into 7 cm pots when they have two true leaves, or sow thinly into the final pot and thin out.

Plant outdoors in June, once nights are warm (above 10°C) and frost risk has gone, or pot on into 15–20 cm pots on a windowsill. Space plants 20–30 cm apart. Basil resents cold and wet; a cloche or greenhouse helps.

Top tips

• Sow after April, with warmth.
• Harden off carefully; basil hates cold.
• Sow new batches every 3–4 weeks.
• Use a bright windowsill.

Water in the morning, at the base of the plant, keeping the compost moist but not soggy, since wet leaves in cool nights encourage rot. Pinch out the growing tips when plants are 15 cm tall for bushy growth, and pinch off flower buds immediately to keep leaves coming.

Feed with a liquid fertiliser every two weeks. Slugs love basil, and aphids and downy mildew can affect plants, especially in damp conditions. Keep plants in good light and airflow, and remove affected leaves.

Top tips

• Pinch out the tips for bushy plants.
• Remove flower buds.
• Water in the morning at the base.
• Watch for slugs.

Watch out for

SlugsDowny mildewAphidsFusarium wiltCold damage

Start picking leaves when plants are 15 cm tall, from about six weeks. Pinch off the tips of stems just above a pair of leaves, which prompts two new shoots, and harvest from the top down rather than stripping individual leaves from the base.

Pick regularly, and never remove more than a third of the plant at once. Harvest before flowering for the best flavour. Pick in the morning, as the flavour is best before the heat of the day. Take all remaining leaves before the first cold nights in autumn.

Top tips

• Pinch above a pair of leaves.
• Harvest before flowers form.
• Never take more than a third.
• Pick all before cold nights.

Add torn leaves to tomato salads, pizza, pasta, soups and sauces at the end of cooking, as heat destroys the flavour. Blend into pesto with pine nuts, garlic, parmesan and olive oil, or make basil oil and basil vinegar. Thai basil suits stir-fries and curries.

Fresh basil keeps best at room temperature with the stems in water, not in the fridge, where it blackens. For longer storage, freeze leaves in olive oil in ice-cube trays, or freeze pesto in portions. Drying loses most of the flavour.

Top tips

• Add at the end of cooking.
• Store stems in water at room temperature.
• Freeze pesto in portions.
• Tear, don’t chop, to avoid bruising.