Basil is a very easy crop to grow from seed for summer harvests. Basil seeds germinate slowly, a bit faster when heated from below, and basil enjoys hot weather and full sun. Each variety has its own charms, but Sweet Basil and Genovese are the standard bearers. Continue reading below for our top tips on how to grow basil from seed.
Ocimum basilicum, Holy basil is O. tenuiflora.
We Recommend: Certified Organic Genovese Basil (HR1019). This is the standard by which to compare all of the other fine basil varieties. Traditional, heirloom, Italian basil is the best choice for pesto.
For Urban Gardeners: Certified Organic Dolly Basil (HR1025) has all the aroma of Genovese, but with slightly larger leaves, faster growth, and a better tolerance of the cool nighttime temperatures that can occur on balconies and rooftop gardens. It’s also slightly better suited for container growing.
Season: Warm season
Exposure: Full sun
Basil grows well in containers indoors at any time of year provided you can supply enough light. For outdoor growing, sow basil seeds throughout late spring for transplanting to the garden after the summer solstice. Or direct sow in early summer, 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.
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.
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.
Frequent harvesting will prolong the life of the plant. Basil leaves have the best flavour 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 chopping tends to bruise the leaves. Add basil to food 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.
Basil is best fresh, but can be preserved by drying or by freezing. To freeze, tear the leaves into small pieces and freeze small batches of them, with water, in ice cube trays. Once frozen, the cubes can be saved in zip-lock type bags and labeled for later use. This will preserve the fresh flavour of basil for up to four months.
Usual seed life: 3 years.
Basil is said to improve vigour and flavour of tomatoes, planted side-by-side. It's also good with asparagus, oregano, and peppers. Basil helps repel flies, mosquitoes, and thrips.
More on Companion Planting.