Timing
Basil grows well in containers indoors at any time of year provided you can supply enough light. For outdoor growing, sow basil seeds from mid-April to mid-May for transplanting to the garden in June, or direct sow in late-May or early June, once the soil has warmed up. Basil requires warm soil and full sun. Optimal temperature for germination: 21°C (70°F). Seeds should sprout in 5-10 days.
Starting
Sow seeds 1cm (½”) deep in sterilized seed starting mix. Basil is prone to damping off, so once seeds sprout, make sure they are adequately ventilated, and kept under very bright light. Thin to 20-25cm (8-10″) apart. Using bottom heat speeds germination.
Growing
Use any rich, loose, well drained soil. Once plants are 15cm (6″) tall, pinch out the growing tips to encourage really bushy growth prior to harvest. Watch for signs of flower buds forming in mid-summer, and pinch these off to promote more foliage.
Harvest
Frequent harvesting will prolong the life of the plant. Basil leaves have the best flavor just before the plant flowers, and if you plan to preserve some of your basil or make a big batch of pesto, this is the best time to harvest. Flowering can be delayed by pinching or clipping off new flower buds.
Tear basil rather than chop with a knife because when you chop you will notice the basil going dark. The oil stays in the leaf and does not properly flavor your food. Try to add just before serving so as to get the full aroma and effect. Cooking for any length tends to make the minty side of basil come to the forefront.