great basil
Ocimum basilicum
great basil (Ocimum basilicum)
H1cTender, protected in winterRHS profile linked · 5–10°C
☀️ Full sun📏 30–150 cm × 10–50 cm🌿 Annual
The Gardening Year
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🌸 In flower
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🖨 Print-friendly care cardAt a Glance
| Botanical name | Ocimum basilicum |
|---|---|
| Common name(s) | great basil |
| Family | Lamiaceae |
| Plant type | annual (can be grown as a short-lived perennial or biennial in warmer horticultural zones with tropical or Mediterranean climates) |
| Height × Spread | 30–150 cm × 10–50 cm |
| Position | Full sun |
| Soil | Moist but well drained soil; loam or sand; fertile; pH Acid, Alkaline, Neutral |
| Flowering | June–August |
| Toxicity | No specific toxicity is listed by the RHS. This is not a guarantee of safety — check with a vet or the ASPCA before pets or children eat any plant. |
| Native range | tropical regions from Central Africa to Southeast Asia |
Overview
Great basil (Ocimum basilicum) is a tender aromatic herb cultivated for its fragrant, glossy leaves, which are used widely in Mediterranean, Southeast Asian and Middle Eastern cookery. It is a member of the Lamiaceae (mint) family and behaves as a half-hardy annual throughout the United Kingdom.
Sowing
Sow indoors from late March to early May on a warm windowsill or in a heated propagator set to 18–21 °C. Surface-sow onto moist peat-free seed compost, press the seed in lightly and cover with a thin layer of vermiculite. Germination usually takes 7 to 14 days. Pot seedlings on once they have two true leaves, handling them by the leaf rather than the stem to avoid bruising.
Growing
Great basil is a warmth- and light-demanding crop. It performs best in a sunny, sheltered position that receives at least six hours of direct sun per day. The plant is not hardy: leaves blacken and die at temperatures below about 4 °C. Soil should be moisture-retentive but sharply drained. The optimum pH is approximately 6.0 to 7.5.
Harvesting
Begin harvesting once plants are well established, typically six to eight weeks after sowing. Pinch out growing tips to encourage bushy branching and continue to pinch out flower spikes as they form to keep the plant in active leaf production.
Eating
Used widely in Mediterranean, Southeast Asian and Middle Eastern cookery. Pesto (with pine nuts, garlic, parmesan, olive oil), tomato and basil salad, Thai curries and stir-fries, garnishes, infused oils and vinegars.
Companion Planting
Grows well with tomato.
Cultivars and Varieties
| Cultivar | Height | Flower | Notes | AGM |
|---|---|---|---|---|
| 'Anise basil, Licorice basil, or Persian basil (O. basilicum ' | — | — | — | |
| 'Cinnamon basil (Ocimum basilicum 'Cinnamon')' | — | — | — | |
| 'Dark opal basil (Ocimum basilicum 'Dark Opal')' | — | — | — | |
| 'Genovese basil or Sweet Basil (Ocimum basilicum)' | — | — | — | |
| 'Globe basil, dwarf basil, French basil (Ocimum basilicum 'Mi' | — | — | — | |
| 'Greek basil (Ocimum basilicum var. minimum)' | — | — | — | |
| 'Lettuce leaf basil (Ocimum basilicum 'Crispum')' | — | — | — | |
| 'Purple Delight' | — | — | purple leaves |
Pests and Diseases
| Problem | Symptoms | Management |
|---|---|---|
| Fusarium wilt | soil-borne fungal disease that will quickly kill younger basil plants | — |
| Pythium damping off | seedlings may be killed by Pythium damping off | — |
| Gray mold (Botrytis cinerea) | common foliar disease of basil | — |
| Black spot (Colletotrichum genus) | seen on basil foliage | — |
| Downy mildew (Peronospora belbahrii) | significant disease | — |
Or browse the full plant problem solver to diagnose an issue by symptom.
Suggested companion plants
✔ Grows well with: tomato.
Full companion planting chart →
