Sweet basil plant with glossy bright green leaves — Photo: gnuckx · CC0

Basil care

Ocimum basilicum · Lamiaceae

Also called Sweet basil, Common basil, Genovese basil.

By the Greenie team · Fact-checked October 5, 2026

A tender, fast-growing herb from tropical Asia, grown for its fragrant leaves. On a sunny, warm windowsill it gives harvests for months, but it sulks in cold or dim spots and is usually treated as an annual.

Pet safe Flowers indoors Fast growing

Light

Full Sun

Watering

Every 2-3 days

Difficulty

Medium

Pets

Non-toxic to cats and dogs

Height indoors

20-45 cm

Growth

Fast

Temperature

18-27 °C

Not below 10 °C

HumidityUnconfirmed

40% - 60%

Average room humidity

Soil pH

6.0-7.5

Neutral soil

Native to

India
Bangladesh
Nepal
Bhutan
Sri Lanka
Myanmar (Burma)
Thailand
Laos
Cambodia
Vietnam
China
Taiwan
Philippines
Malaysia
Brunei
Indonesia
Timor-Leste
Papua New Guinea
Australia

Through the year

Keep the compost evenly moist but never soggy; water at the base in the morning so the roots are not wet overnight.

Spring
Every 2-3 days
Sow seed or buy plants and keep them on a warm, sunny sill.
Summer
Every 2-3 days
Peak season: harvest often, pinch flowers and water regularly.
Autumn
Weekly
Take cuttings in water to keep plants going indoors as nights cool.
Winter
Weekly
Hard to keep going: give it the warmest, brightest spot or a grow light, and water less.

Feeding

Every 2 weeks in spring and summer. Balanced liquid fertilizer at half strength. Overfeeding weakens the flavour.

Care tips

Split supermarket pots
Those pots hold many crowded seedlings; divide them into 3 or 4 clumps in fresh compost so they last.
Harvest from the top
Cut each stem just above a pair of leaves so two new shoots grow.
Pinch off flowers
Flowering makes the leaves less tasty and slows new growth.
Add a grow light in winter
Short days are not enough; 12 to 14 hours under a lamp keeps it productive.
Use a big enough pot
A pot at least 15 to 20 cm wide with drainage holes dries out less often.

Common problems

Downy mildew

What you seeLeaves yellow between the veins with grey-purple fuzz on the undersides.

What to doRemove and bin affected plants, water at the soil only, improve air flow and choose a resistant variety next time.
Cold damage

What you seeLeaves blacken, droop or show dark patches after a cold night.

What to doMove it off the windowsill on cold nights and keep it above 10 °C at all times.
Leggy, flowering stems

What you seeTall, thin stems with few leaves and flower spikes forming.

What to doGive it more direct sun and pinch out the tips and flower buds regularly.