How to grow basil

Basil is a versatile annual herb used in pasta sauces, pizzas, salads and Thai curries. It is a member of the Lamiaceae (mint) family. Sweet basil plants tend to dominate the supermarket shelves, but there are many other exciting types to try when you grow your own.

How to grow basil

Sow basil seed successionally from spring to summer so you have a continuous crop. Pot on into individual pots when plants are big enough to handle. Water sparingly as basil suffers when sitting in wet compost. Harvest leaves using scissors or snips, cutting a lead stem just above a pair of leaves – this way, the plant will become bushier and more productive over time.

Basil is an essential topping for homemade pizzas and a key ingredient for many tomato sauces. Check out our tests of the best pizza ovens, in collaboration with BBC Good Food.

How to sow basil seed

Grow basil in well-drained, fertile soil in a warm, very sheltered position with plenty of light but preferably not too much direct midday sun, which can scorch the leaves a little. To get a quality crop that lasts from early spring to mid-autumn, it’s best to grow basil in a greenhouse or polytunnel, or on a warm, light windowsill.

Start your basil seeds off in pots of moist peat-free seed compost or good quality multi-purpose compost on a warm (around 20°C), bright windowsill out of direct sun. Water sparingly until germination, then water only when needed. When seedlings are big enough to handle, pot them on into individual pots filled with a peat-free, soil-based compost mixed with multi-purpose compost. Pinch out tips to encourage bushy plants.

Keep potted basil plants indoors or plant outside in warmer locations, in the ground or a container, in a sunny and very sheltered spot, from June to August. To acclimatise plants to conditions outdoors, stand them outside in a sheltered, lightly-shaded spot during the day, and bring the basil pots back in at night. Do this daily for about two weeks.

Watch Monty Don plant out basil with tomato plants, in this clip from BBC Gardeners' World:

Did you know...

In Elizabethan times, sweet basil leaf was dried and used as a snuff to treat headaches and colds. It is also seen as a sacred plant – some Greek Orthodox churches use Greek basil to prepare their holy water and, at Hindu weddings, the parents of the bride traditionally present the groom with a basil leaf.

How to care for basil plants

When growing basil, one of the most important things to remember is to water – if the soil becomes too dry, they'll quickly wilt. Don't let the plants sit in water though, as this can cause the roots to rot.

Outdoors, basil plants need protection from wind and cold air. Always water with care, ideally before midday, and avoid splashing the leaves. This should help prevent botrytis (powdery mould).

Plants will grow quickly in containers, so expect to pot them up a few times during the growing season. When basil flowers, it affects leaf quality. To avoid basil plants flowering, remove any flower stems as soon as possible. Towards the end of the season you could let some basil flowers bloom, to provide nectar for bees and butterflies.

Basil is a half-hardy annual, so new plants will be needed each year. However, in autumn, when temperatures start to dip, bring a few plants back indoors to provide a fresh supply of leaves over winter.

How to grow supermarket basil

Most fresh basil sold in supermarkets is sweet basil. It takes just 22 days from seed to sale, and lots of plants will have been squeezed into a small space, so the rootball will be fairly weak and underdeveloped. This is why it normally dies if you plant it in the garden. If you want to keep your basil plants alive, tip the plants out of their pot and tease their roots apart to separate them. Replant individually into pots of soil-based compost. Keep them moist but not wet, and place them somewhere warm but not in direct sun. When you see roots through the drainage holes in the pot base, harden off and plant out in the garden.

Pests and diseases

Protect plants from snails and slugs. Basil is also prone to attack by whitefly and red spider mite. It can also be susceptible to grey mould and powdery mildew, so ensure that plants grown in a greenhouse have good ventilation around them.

How to harvest basil

Pick the leaves and tops of basil regularly throughout the summer. You can be quite ruthless, as long as you leave at least three pairs of side shoots so your plants can regrow. Don’t wash the leaves until you’re ready to use them as they’ll turn slimy.

Preparing and using basil

Aromatic basil is a key ingredient in the kitchen and can be used in salads, pesto, pasta sauces and Thai curries. Basil plant is attractive, well-suited to growing in containers and makes a perfect planting partner for tomatoes, which enjoy similar warm, sheltered growing conditions and can also help the basil by casting a little shade at the hottest times of day.

Eat leaves raw and as fresh as possible. Here are our tips on how to pick herbs to ensure they don't run to seed and cut short your harvests. For the best flavour, add fresh basil at the end of cooking. It’s said that you should tear rather than chop basil leaves to release their wonderful aroma. Use in salads, soups, stews, to make pesto and other sauces, particularly any recipe containing tomatoes. And when the evenings become colder in autumn, bring your plants indoors to a warm, bright place to continue picking them.

Here, Monty Don demonstrates how to make pesto using fresh basil from the garden:

Storing basil

Basil is best used fresh. It is difficult to dry or freeze well. You can stand cut stems in a glass of water in a cool spot for a few days ready to use, providing the water is changed every day.

Basil varieties to grow

'Sweet' (Genovese)

Basil 'Sweet' (Genovese), Ocimum basilicum, is the most popular variety of basil, with large, soft leaves and a sweet taste. It's great raw with tomatoes and is widely grown in Italy for use in pesto.

Basil 'Crimson King'

Ocimum basilicum 'Crimson King' is a British-bred, purple-leaved variety with uniform, 'cupped' leaves and greater vigour than other purple varieties. The unusual colour of this basil plant means it looks great in containers or window boxes, combined with other plants - try this tomato, basil and calendula pot.

Basil 'Greek'

Greek or 'bush' basil (Ocimum basilicum var. minimum 'Greek') has smaller leaves than sweet basil, with a slightly sweeter, anise-clove flavour. Use them to make pesto or add to tomato sauces or pizzas. Its neat, compact shape makes it ideal for a container.

Basil 'African Blue'

Ocimum basilicum 'African Blue' has attractive purple-blue flowers (much-loved by bees) and purple-veined leaves. It's larger than other basils, reaching 75cm, and looks great in a pot or in a border. This basil plant is a tender perennial so will need protection over winter.

Thai basil

Ocimum tenuiflorum, also known as sacred or holy basil, or tulsi, is a small variety with purple-green serrated leaves and purple stems. It originates in Thailand and therefore is the perfect basil to use in Thai dishes.

Basil 'Cinnamon'

Ocimum basilicum ‘Cinnamon’ has spikes of mauve flowers and purple-veined leaves with a very spicy cinnamon flavour and hints of cloves. Good for stir-fries.

Basil 'Red Rubin'

Ocimum basilicum var. purpurascens ‘Red Rubin’ produces highly aromatic, deep purple leaves and mauve-pink flowers. Suitable for ornamental and herb beds. Grows to 45cm.