Why does my basil keep dying?

Basil is a warm-climate annual grown for a short intense season. It hates cold, hates wet leaves, hates being waterlogged and hates being cut from the bottom, which covers most of what goes wrong with it.

What you'll need

• Fresh compost
• Small pots
• Bright warm windowsill

Step by step

1. Split a supermarket pot immediately.There may be fifty seedlings in one small pot. Tease it into three or four clumps and pot each into fresh compost in a slightly larger pot.
2. Give it as much light as you have.Basil needs full sun. A south-facing windowsill, a greenhouse, or outside from June. In poor light it goes leggy and pale and then rots.
3. Keep it warm.Below about 12C it stops growing and the leaves blacken. Outdoors in the UK it is only reliable from June to September, and a cold night in May will finish it.
4. Water in the morning, at the roots.Basil is very prone to fungal rot at the base. Water into the compost, never over the leaves, and never in the evening.
5. Let the surface dry between waterings.Constantly wet compost causes stem rot at soil level. It should be moist below and dry on top.
6. Pinch out the growing tips.Take the top pair of leaves off each stem regularly, above a pair of side shoots. This produces a bushy plant instead of a single stem that flowers and dies.
7. Remove flower buds immediately.Once basil flowers, leaf production stops and the flavour changes. Pinch out flower spikes as soon as they appear.
8. Harvest from the top, not the bottom.Picking lower leaves leaves a bare stem and encourages flowering. Taking the top growth keeps the plant branching.
9. Feed lightly once established.A weak liquid feed every couple of weeks once the plant is growing well. Overfeeding produces soft growth that rots.
10. Sow your own for a proper season.Basil sown in April on a warm windowsill and potted on produces a far better plant than a supermarket one, and several sowings give a supply all summer.

Tips

• Supermarket basil is fifty plants in one pot. Split it the day you get it home.
• Water in the morning, at the roots. Wet leaves overnight is what kills it.
• Pinch the tops out. Harvesting from the bottom guarantees a leggy plant that flowers and dies.

Common mistakes

• Standing the pot in a saucer of water — Basil stems rot at soil level in constantly wet compost. It needs free drainage and a surface that dries between waterings.
• Putting it outside in May — A single cold night blackens the leaves and often kills the plant. Basil goes outside in June at the earliest and comes in again in September.

If it doesn't work

Questions people ask