Basil

How to choose basil plants

Pure Italian Basil is classic sweet basil, the one for pesto, tomato salads and pasta. Roman Ruby Basil is a red leaved basil that adds colour to salads and to the herb bed. Gusto Basil and Profusion Basil are further named selections of the same species, Ocimum basilicum, and are grown in exactly the same way.

If you cook with basil often, grow several plants. One plant gives a handful of leaves a week. A batch of pesto takes most of a bush.

Where basil grows

Basil grows in every Australian climate during the warm season. In cool and mild temperate districts, including Melbourne, Adelaide, Hobart, Canberra and Perth, plant from October or November, once frosts are over and the nights have warmed, and harvest until April. Basil planted into cold soil sits still and often rots. In the subtropics the season runs from September to April. In the frost free tropics basil grows almost all year, and it is easier through the dry season than in the wet. A pot on a warm, sunny windowsill will carry a plant on indoors when it is too cold outside.

Basil sits naturally with our other edible plants and is one of the easy plants for pots on a sunny balcony or step.

Planting and spacing

Give basil at least six hours of sun. In hot inland summers a little afternoon shade stops the leaves scorching. Dig compost through the soil first, because basil is a leafy, hungry plant. Space plants 25 to 30 centimetres apart. In pots, use a container at least 20 centimetres wide for each plant and a good quality potting mix. Basil is a traditional companion for tomatoes, and the two like the same sun, soil and watering.

Care basics

Water regularly, in the morning and at the base, so the soil stays moist but not sodden. Feed with a liquid fertiliser every fortnight. Start pinching when the plant is about 15 centimetres tall: nip out each tip just above a pair of leaves, and two new shoots will grow from that point. Remove flower buds as soon as they appear. Once basil flowers and sets seed, the leaves become smaller and coarser. Harvest from the top of the plant rather than stripping the lower leaves. In humid weather, space plants for air flow and keep water off the foliage to limit fungal leaf diseases. Protect young plants from snails and slugs.

Common questions

When should I plant basil?

After the last frost, when nights are reliably mild: from October or November in the south, September in the subtropics, and most of the year in the frost free north.

Why is my basil going to flower?

Flowering is triggered by heat, dry soil and maturity. Pinch out the buds as they form, keep the water up and harvest often to keep leaves coming.

Is basil an annual?

Sweet basil is grown as a warm season annual. Cold weather finishes it, and frost kills it outright, so replant each year.

Can I grow basil indoors?

Yes, on a bright windowsill with several hours of direct sun. Without enough light it grows thin and pale.