Ocimum basilicum

Sowing, spacing and care guidance

Start Ocimum basilicum seeds in warmth indoors, sowing shallowly in trays or modules. Provide bright light and steady moisture; avoid waterlogging. Pot on when seedlings have 2–3 true leaves, then harden off and transplant after last frost into full sun to light shade and well-drained, moderately fertile soil. In warm soils, direct sowing is also possible. Space plants to promote airflow, as per packet guidance, and keep the root zone evenly moist. Pinch growing tips to encourage branching and a compact to medium habit, and remove flower spikes if leafy growth is desired. Feed lightly during active growth. Protect from cold nights and drying winds.

• Start indoors warm; transplant after last frost; direct sow only when soil is warm.
• Full sun to light shade; well-drained, moderately fertile soil; avoid waterlogging.
• Space to promote airflow; follow packet guidance; pinch to keep a compact to medium habit.
• Container suitable: Suited to containers; use a free-draining mix and maintain even moisture.
• Pollinator friendly: If allowed to flower, blossoms may attract pollinating insects.
• Edible: Grown for culinary leaves; harvest regularly to encourage fresh growth.

When should I plant Ocimum basilicum seeds after the last frost?

Start Ocimum basilicum seeds indoors in steady warmth, then transplant outside only after the last frost when nights are reliably mild. For direct sowing, wait until soil is consistently warm and workable; basil performs best when soil stays around 18–21°C or warmer and night temperatures no longer dip below about 10–12°C. Harden off indoor-raised seedlings gradually over a week to adjust to outdoor light and breeze. In mild climates, a late spring or early warm-season sowing gives the strongest plants; avoid cold, windy sites early in the season.

What soil and light conditions do sweet basil seeds need?

Basil thrives in full sun to light shade with at least several hours of direct light each day. Choose a well-drained, moderately fertile soil that never sits waterlogged; heavy, compacted ground slows growth. Improve drainage with coarse organic matter or grit if needed, and avoid overly rich nitrogen levels that can lead to soft, leggy growth. A neutral to slightly alkaline pH suits most sweet basil types. In containers, use a free-draining mix with added perlite, and ensure pots have ample drainage holes to prevent root stress.

What temperature do basil seeds need to germinate?

Basil germinates best warm: 21–27°C is ideal, with the fastest sprouting often at 24–27°C. Below about 18°C, germination slows and seedlings can stall. Sow seeds shallowly—just covered by 3–5 mm of fine mix—or surface sow and lightly press in, then keep evenly moist but never waterlogged. With proper warmth and moisture, expect emergence in roughly 5–10 days. Good air circulation reduces damping off; bottom heat or a warm indoor spot helps maintain a steady temperature while seedlings establish.

How do I start basil seeds indoors and grow them in containers?

Sow 2–3 seeds per cell or small pot, thin to the strongest seedling, and maintain steady warmth and bright light to prevent stretch. Transplant to individual 7–9 cm pots when true leaves appear, then harden off before moving outside. For containers, give each plant a 15–25 cm pot, or group several in a 30–40 cm wide planter, using a free-draining mix. Water when the top 2–3 cm of mix dries; in warm weather, morning deep watering helps, while pots may need daily checks. Feed lightly with a balanced, dilute fertiliser during active growth.

How far apart should basil plants be, and how tall do they get?

Most sweet basil types are compact to medium, typically 30–60 cm tall and 25–45 cm wide depending on variety and conditions. Space plants about 25–30 cm apart to allow good air flow and easy harvesting; wider spacing suits vigorous varieties or humid sites. In containers, give each plant enough room so leaves are not crowded against neighbours. Regular pinching encourages a bushier habit and helps keep height manageable, while also improving air movement through the canopy.

How do I prune and harvest basil to keep it bushy and delay flowering?

Begin pinching once plants reach about 12–15 cm tall: cut just above a leaf pair, which prompts two new shoots and a fuller shape. Harvest little and often, taking stems rather than single leaves, and avoid removing more than one-third of the plant at a time to maintain vigor. Snip off any flower buds as they appear to prolong leafy growth; if allowed to bloom for pollinators, expect leaf production to slow. Keep plants evenly watered and unstressed, as drought and heat can hasten flowering.

Information summarises standard horticultural practice drawn from reputable references and in-house trials. Conditions and results vary with microclimate, soil structure, fertility, and seasonal patterns (for example, timing after last frost or when soil is workable). Guidance is general; product pages provide crop-specific instructions, including sowing depth, spacing, and timing, where applicable. Always consider local conditions and site history when interpreting general guidance.

Reliable Tips for Cultivating Sweet Basil

Ocimum basilicum seeds prosper in warmth, so start indoors 6–8 weeks before the last frost or sow directly outdoors once the soil is reliably warm and workable. In mild climates, protected autumn sowing may be possible. Use a free‑draining, fertile mix and cover seeds lightly, as light aids germination. Maintain even moisture and warmth, then provide bright light to prevent legginess. Transplant after frost danger passes, spacing plants 20–30 cm apart in a sunny, sheltered position. Water at the base and mulch to conserve moisture. Pinch growing tips early to encourage bushiness and delay flowering; remove flower spikes to extend leaf production. Harvest regularly by taking upper stems rather than individual leaves, allowing regrowth from lower nodes. In containers, choose a pot with good drainage and feed lightly during active growth. Companion flowers that attract pollinators nearby can support overall garden health without compromising leaf quality. Additional variety information and seed specifications are available from SeedsChoice.