How to Grow Holy Basil
Ocimum tenuiflorum
Holy basil (Tulsi) needs warmth, full sun, and well-drained soil. Sow indoors in late spring at 20-30°C and plant out only after all frost risk has passed. More heat-tolerant and vigorous than sweet basil, reaching 30-60cm with purple-tinged stems. Pinch tips for bushy growth but flowers can be left for their medicinal value. Harvest leaves regularly for a stronger, more peppery-clove flavour than sweet basil. Perennial in the tropics but treat as a frost-tender annual in the UK. Excellent in Thai and Indian cuisine.
When to Start
Start seeds indoors 4 weeks before your last frost date. Transplant outdoors once night temperatures stay above 12°C and soil has warmed to at least 20°C.
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Growth Stages
Approximate days from start
Care Essentials
- Light liquid feed every 2-3 weeks during active growth. Less demanding than sweet basil.
- Sacred plant in Hinduism (Tulsi). Perennial in tropics but grown as annual in UK. More heat-tolerant than sweet basil. Purple-tinged stems and flowers.
Growing Conditions
- Min. soil temperature
- 20°C+
- Germination temperature
- 20–30°C
Pet Safety
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- Sow indoors
- —
- Transplant out
- —
- First harvest
- —
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Spacing & Planting
| Plant spacing | 30 cm |
| Row spacing | 40 cm |
| Sow depth | 0 cm |
| Mature height | 60 cm |
| Mature spread | 40 cm |
Larger and more vigorous than sweet basil. Needs good air circulation around stems to prevent fungal issues in humid conditions.
Growing Conditions
| Min. soil temperature | 20°C |
| Germination temperature | 20–30°C |
| Base growth temperature | 12°C |
| Min. daylength to start | 11h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Holy Basil?
- Plant Holy Basil 30cm apart with 40cm between rows.
- When can I harvest Holy Basil?
- Holy Basil is ready to harvest approximately 45 days after transplanting.
- Is Holy Basil frost hardy?
- Holy Basil is classified as Tender.
