Stop letting your basil flower.
Once basil flowers the leaf slows and the flavour drops. Pinch above a leaf pair and two shoots grow back.
Sweet basil is grown as an annual and its whole plan is to flower and set seed. Once it flowers, leaf production slows and the flavour drops off. Keep it in leaf by pinching or snipping the growing tip just above a pair of leaves, which makes the plant branch, and by taking the tips every time you pick rather than stripping single leaves. Pinch out flower spikes the moment they show, and plant basil out only once frosts are done and the soil has warmed.
The basil that came home in a pot was a single stem with a tuft of leaves on top. It was picked from the bottom up, leaf by leaf, until it was a bare stalk with a flower on the end, and then it was declared finished.
It was not finished. It was never pinched.
Why basil flowers, and what that costs you
Sweet basil is grown as an annual, and an annual's job is to flower and set seed before the season ends. Gardening Australia's Josh Byrne puts it plainly: you cannot prevent basil bolting to seed, as all annuals do this at the end of their short life cycle. What you can do is delay it. Once a plant flowers, leaf production slows and the flavour drops off, which is why the Gardening Australia plant guide says to pinch out flower buds as they appear. Flowering is the plant changing jobs. Pinching keeps it in the leaf business.
How to pinch
Look down the stem to the first pair of leaves below the growing tip. Pinch or snip the stem just above that pair. Basil carries its leaves in opposite pairs with a bud at the base of each, so new shoots push out from that pair and one stem becomes two. Do it again on each new shoot a few weeks later and two become four, and you have a bushy plant with far more leaf than the single stalk you started with.
Hannah Moloney's rule on Gardening Australia is the one to remember: rather than pulling off the top leaves, snip the stem just above the next layer of leaves down, and the plant grows bushier rather than tall and leggy.
When to start, and how to keep picking
Start once the plant is about 15 to 20 centimetres tall with three or four pairs of leaves, usually two to three months from sowing and sooner in warm weather. From then on, pick often, and pick from the top. Take the tips, cutting above a leaf pair, rather than stripping single leaves off the bottom, and never strip a plant bare; leave plenty of leaf below so it can regrow.
Pinch out flower spikes the moment they show. They keep coming through summer, so this is a weekly job rather than a one-off. At the end of the season let one plant flower for the bees, and save the seed.
When to plant it out, city by city
Basil is frost tender and it sulks in cold soil. Plant it out in full sun once frosts are done and the soil has warmed to about 16 to 18°C, or when self-sown nasturtiums start coming up on their own, which Gardening Australia's Millie Ross uses as the signal that the soil is warm enough for beans, basil and cucurbits.
- Brisbane, the Gold Coast and the Sunshine Coast: the season is long, and a plant kept pinched can carry through to autumn.
- Perth: from October as the soil warms, and a plant kept pinched can carry through to autumn.
- Sydney, Newcastle and Wollongong: from late September into October as the soil warms.
- Adelaide, Melbourne and Geelong: from mid to late October.
- Canberra, Hobart and the cold hills: late October or November, once frost risk has passed.
Water, pots and the kitchen
Basil wants regular water and good drainage. A pot of basil wilts fast on a hot day, so water it every couple of days and daily in heat, and mulch the pot. It bruises easily and the leaves can blacken in the fridge, so pick it fresh, or do what many cooks do and stand the stems in a glass of water on the bench like cut flowers.
Basil and tomatoes are old bedmates because they like the same soil, water and warmth. The pest-repelling story is unproven; plant them together because they like the same conditions and eat well together.
Grow it: seeds in stock
Three basils from the range, and a second sowing a few weeks after the first keeps young leafy plants coming as the older ones tire.
Basil Large Sweet Italianthe classic big-leafed sweet basil for pesto and tomato sauces, and the plant that shows the pinching lesson best.See the seeds
Basil Siam Thai QueenThai basil with an aniseed, liquorice note, purple stems and mauve flowers if you let it.See the seeds
Basil Purple Firedeep purple leaves, used just like sweet basil.See the seeds
Pinch above a leaf pair and two shoots grow back. That is the whole lesson, and it can turn one pot of basil into a summer of it. Basil is also among the last seedlings out of the door in spring, and our lesson on hardening off seedlings covers the week outside that gets it there.
Frequently asked questions
My basil has already flowered. Is it finished?
No. Pinch out every flower spike, cut each stem back to just above a leaf pair, water and feed lightly, and it usually comes back into leaf. Flavour is reduced while basil flowers, so the leaves that follow are usually better than the ones it grew while flowering.
Can I take cuttings?
Yes. A 10 to 15 centimetre tip cutting roots in a jar of water or in seed-raising mix, cut just below a leaf node with the lower leaves removed.
Does basil keep tomato pests away?
There is little evidence for it. One Sustainable Gardening Australia writer planted a basil beside every tomato for years and noticed no difference. Grow them together because they like the same conditions and the same plate.
