Basil (Ocimum basilicum) is a member of the mint family. There are several types of basil. The most common culinary type is sweet basil. Specialty types include Thai, purple, lemon and small-leaved bush types. Basil seed is not always true to type. Try to obtain high quality seed that is uniform with a high germination percentage.

Varieties

• Sweet/Pesto: Genovese, Italian Large Leaf, Nufar (FR), Aroma 2 (FR)
• Thai: Sweet Thai, Siam Queen, Thai Magic
• Purple: Dark Opal, Purple Ruffles, Osmin Purple, Magical Michael, Red Rubin
• Bush: Spicy Globe, Spicy Bush
• Scented: Sweet Dani (lemon), Lime, Holy (medicinal)

FR = resistant to Fusarium wilt

Soil Fertility

Basil grows well in a warm, well-drained soil with pH 6.0-7.5. Although adequate fertility is required (see table), excess nitrogen applications can cause post-harvest discoloration and reduce flavor. Basil benefits from a sidedress application of nitrogen after the first or second cutting.

Planting

Because it is highly sensitive to cold, basil should not be seeded or transplanted until after danger of frost. Basil seeds will germinate within 8 to 14 days at soil temperatures between 65°F and 80°F, with an optimum of 70°F. If field soils are warm enough, basil can be direct-seeded in a well-prepared seedbed at a spacing of eight to 10 seeds per foot and later thinned. Basil can be direct sown using an onion seeder. Pelleted seeds are also available to facilitate seeding. For direct seeding in double rows, 10 oz unpelleted seed are needed per acre (1/8 oz. seed per 100 feet of row).

Basil is most commonly transplanted. Prior to transplanting, plants should be 6” tall (four to six weeks old). Topping when the plants are 5-6” tall encourages branching. Basil is often grown at a spacing of 6” to 12” between plants in double-rows on black plastic mulch on beds 2’ to 4’ wide. When transplanting, 17,000-34,000 plants are needed per acre (200-400 plants per 100 feet of row) at 5 foot row spacing.

Field Culture

Basil requires adequate soil moisture throughout the growing season. Drip irrigation allows consistent application of water while also reducing foliar diseases. Cultural management of insects, diseases and weeds are necessary because few insecticides, fungicides and herbicides are registered for use on basil. Because of the lack of herbicides for weed control, and the need for warm temperatures, basil is well suited to being grown on raised beds covered with black plastic mulch.

Harvest and Storage

Basil is first harvested 60 to 70 days after seeding. Harvests should take place in the morning after the dew has left the plants. Depending on the intended use and market, individual leaves or entire tips of stems may be harvested. Plants may be harvested every one to seven days, depending on the amount removed. Basil can grow up to 1” per day and can be harvested one to five times throughout the season. Basil grown for culinary use should be harvested before flowering. Basil grown for essential oil production should be harvested at full bloom. Plants will set seed if flower spikes are not removed as they appear. Sequence plantings can help ensure continuous production.

Fresh basil is easily damaged by rough handling, dessication and chilling (<40°F). Basil can be cooled by rinsing in cool (55°F) water, but should be dried completely prior to packing. Basil should be stored at temperatures above 54°F.