Basil - Cultivation

Cultivation

Most culinary and ornamental basils are cultivars of the species Ocimum basilicum, but other species are also grown and there are many hybrids between species. Traditionally a green plant, some varieties, such as 'Purple Delight' have leaves that appear purple.

Basil grows between 30–130 cm tall, with opposite, light green, silky leaves 3–11 cm long and 1–6 cm broad. The flowers are small, white in color and arranged in a terminal spike. Unusual among Lamiaceae, the four stamens and the pistil are not pushed under the upper lip of the corolla, but lie over the inferior lip. After entomophilous pollination, the corolla falls off and four round achenes develop inside the bilabiate calyx.

Basil is very sensitive to cold, with best growth in hot, dry conditions. It behaves as an annual if there is any chance of a frost. In Northern Europe, Canada, the northern states of the U.S., and the South Island of New Zealand it will grow best if sown under glass in a peat pot, then planted out in late spring/early summer (when there is little chance of a frost). Additionally, it may be sown in soil once chance of frost is past. It fares best in a well-drained sunny spot.

Although basil grows best outdoors, it can be grown indoors in a pot and, like most herbs, will do best on an equator-facing windowsill. It should be kept away from extremely cold drafts, and grows best in strong sunlight, therefore a greenhouse or row cover is ideal if available. They can, however, be grown even in a basement, under fluorescent lights.

If its leaves have wilted from lack of water, it will recover if watered thoroughly and placed in a sunny location. Yellow leaves towards the bottom of the plant are an indication that the plant has been stressed; usually this means that it needs less water, or less or more fertilizer.

In sunnier climates such as Southern Europe, the southern states of the U.S., the North Island of New Zealand, and Australia, basil will thrive when planted outside. It also thrives over the summertime in the central and northern United States, but dies out when temperatures reach freezing point. It will grow back the next year if allowed to go to seed. It will need regular watering, but not as much attention as is needed in other climates.

Basil can also be propagated very reliably from cuttings with the stems of short cuttings suspended for two weeks or so in water until roots develop.

Once a stem produces flowers, foliage production stops on that stem, the stem becomes woody, and essential oil production declines. To prevent this, a basil-grower may pinch off any flower stems before they are fully mature. Because only the blooming stem is so affected, some stems can be pinched for leaf production, while others are left to bloom for decoration or seeds.

Once the plant is allowed to flower, it may produce seed pods containing small black seeds, which can be saved and planted the following year. Picking the leaves off the plant helps "promote growth", largely because the plant responds by converting pairs of leaflets next to the topmost leaves into new stems.