Basil

Basil (Ocimum basilicum) is a fragrant herb in the mint family, native to tropical regions of Africa and Asia. It is a warm-season, sun-loving herb grown as an annual, and it can’t take frost: in cool climates such as the UK it isn’t hardy and needs plenty of warmth and sun.

Start seeds indoors. Indoor sowing gives earlier, more reliable germination and a longer growing season. Sow seeds about ¼ inch (6 mm) deep; they germinate in 5 to 10 days at 65–70 °F (18–21 °C). Sow four to six weeks before you plan to move the plants outdoors.

Move plants outside only when it’s warm. Keep young plants indoors until after the last frost. Wait until daytime temperatures are consistently in the 70s °F (about 21–26 °C) and nights stay above 10 °C (50 °F).

Choose a warm, sunny spot. Basil prefers full sun but grows reasonably well with about six hours of sun a day. It grows best in rich, well-drained soil with a pH between 6.0 and 6.5.

Pots work well. Basil is often more successful in containers than in the ground; choose a pot at least 20 cm (8 in) wide and deep.

Watering. Basil needs well-drained soil but a fairly constant supply of moisture. Water in the morning if you can, because basil dislikes wet roots overnight, and keep water off the leaves, which makes disease more likely.

Feeding. Don’t over-fertilize: fast growth reduces the flavor of the leaves.

Pinching. For the best-flavored leaves, pinch out flower buds as soon as they appear. Taking a few shoot tips from each plant encourages bushy growth.

Basil is generally easy to grow, though slugs, snails and aphids can cause problems. In the US, Japanese beetles are also among the most common pests.

The most serious disease is basil downy mildew, which spreads through wind-blown spores and infected seed. Fusarium wilt also affects basil; remove and dispose of wilting plants promptly. In a greenhouse, good ventilation helps reduce fungal diseases.

Pick leaves as you need them throughout the summer: take single leaves, or pinch off branch tips with one or two sets of leaves. Start with light picking once the plants are established.

Fresh basil doesn’t keep long, even in the refrigerator, and it shouldn’t be stored below 50 °F (10 °C). Dried leaves keep for up to 12 months in small airtight containers, and pesto freezes well without losing flavor or color.

Pet poison experts list basil as non-toxic to cats and dogs. Don’t can pesto or other herbs in oil at home: it carries a risk of botulism. Freeze pesto instead.