Basil
Ocimum basilicum
Sweet basil is the essential Mediterranean herb, prized for its aromatic, slightly peppery leaves used fresh in salads, pasta, and pesto. A tender annual in the UK, it needs warmth and shelter to thrive. Grow it on a sunny windowsill, in a greenhouse, or outdoors in a sheltered spot after all frost risk has passed. Regular pinching encourages bushy growth and delays flowering, extending the harvest from June to September.
How to grow basil
Sow seed indoors from March to May on the surface of moist compost at 20-25 degrees Celsius. Do not cover — basil seed needs light to germinate. Seedlings emerge in 7-14 days. Pot on into individual 10 cm pots when true leaves appear. Plant outdoors only after all frost risk has passed, typically late May or June in most of the UK. Choose a warm, sheltered spot in full sun. Basil hates cold, wet conditions and will sulk below 10 degrees. Water regularly but never allow roots to sit in water. Pinch out the growing tips when plants reach 15 cm tall to encourage branching and more leaf production. Remove flower buds as they appear — once basil flowers, leaf production slows and flavour diminishes. Harvest leaves frequently from the top of the plant. Successional sowings every three weeks provide a continuous supply.
Pruning
Pinch out growing tips regularly and remove flower spikes as they appear. Harvest by cutting stems above a leaf pair to encourage bushier regrowth.
Propagation
- Seed (sow indoors March-May)
- Stem cuttings in water (root in 7-10 days)
Common problems
- Cold damage below 10 degrees Celsius
- Aphids
- Grey mould in humid conditions
- Damping off in overwatered seedlings
- Slugs outdoors
Good companions
Related guides
How to Grow Basil in the UK
Practical UK guide to growing basil from seed. Covers sowing times, best varieties, pinching tips for bushy growth, and storing your harvest.
How to Grow Herbs in the UK
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