How to Grow Basil

Overview

Basil is a tender, aromatic herb that is essential in Mediterranean cooking and pairs perfectly with tomatoes. While it originates from warm climates, basil can be grown successfully in home gardens with protection and warmth. Greenhouse or windowsill growing produces the most reliable results in cooler climates.

Health Benefits

Vitamin K content: Basil is a surprisingly good source of Vitamin K, with even a small amount of fresh leaves contributing to healthy blood clotting and bone metabolism.

Anti-inflammatory compounds: Basil contains eugenol and other compounds that have been studied for their potential anti-inflammatory effects.

Essential oils with antibacterial properties: The aromatic essential oils that give basil its wonderful scent, including linalool and citronellol, may have natural antibacterial properties, making homegrown basil as beneficial as it is delicious.

Soil Preparation

Basil needs well-drained, fertile soil in the warmest, most sheltered spot you can find. It thrives in containers on sunny windowsills, in conservatories, or in greenhouses. Use a good-quality peat-free potting compost mixed with perlite for container growing. The ideal pH is 6.0 to 7.0.

Sowing & Planting

Sow seeds indoors from March to May, scattering thinly on the surface of moist compost (basil needs light to germinate). Cover with a thin layer of vermiculite and keep at 20-25°C. Germination takes 7-14 days. Transplant seedlings into individual pots when they have two true leaves. Plant outdoors only after all risk of frost has passed, typically June.

Care & Maintenance

Water regularly but avoid waterlogged soil, which causes root rot. Pinch out the growing tips regularly once plants have 6 sets of leaves to encourage bushy growth and prevent flowering. If flowers appear, remove them promptly as flowering reduces leaf production and flavour. Feed fortnightly with a balanced liquid fertiliser.

Harvesting

Pick leaves regularly from June to October, always taking from the top of the plant to encourage branching. Harvest in the morning when the essential oils are most concentrated. Use leaves fresh as they lose flavour when dried. At the end of the season, make batches of pesto or freeze leaves in olive oil in ice cube trays.

Common Problems

Cold damage is the biggest risk, as basil cannot tolerate temperatures below 10°C. Keep plants indoors or in a greenhouse until summer, and bring in again from September.

Aphids can cluster on soft growing tips. Spray with diluted soapy water or wash them off under a tap.

Downy mildew causes yellowing on the upper leaf surface and grey fuzz beneath. Improve ventilation and avoid overhead watering.

Companion Planting

Basil is a classic companion for tomatoes and peppers, reportedly improving their flavour and helping to repel aphids and whitefly. Avoid planting near sage, which is thought to inhibit basil's growth.