Basil (Ocimum basilicum) is an erect herbaceous annual plant, sometimes grown as a short-lived perennial in some areas. It grows in a bushy shape to about 50 cm tall and some varieties may even grow taller.
There are many varieties of Ocimum basilicum, as well as several related species or species hybrids also called basil. The type used in Italian food is typically called sweet basil, as opposed to Thai basil (O. basilicum var. thyrsiflora), lemon basil (O. X citriodorum) and holy basil (Ocimum tenuiflorum), which are used in Asia. While most common varieties of basil are treated as annuals, some are perennial in warm, tropical climates, including holy basil and a cultivar known as ‘African Blue’.
Climatic and soil requirements
The optimum temperature for germination is 20 °C with growing temperatures of 7 to 27 °C. The minimum annual rainfall for dryland cultivation is 700 mm. Basil requires well-drained soils with an optimum pH of 6.4.
Basil’s leaves are used as a seasoning herb for a variety of foods but has become ever popular as the main ingredient in pesto, the mixture of basil, pine nuts and parmesan cheese. Essential oil of basil, obtained from its leaves, is used to flavour foods, in dental and oral products, in fragrances, and as a fresh or dried market herb.
Basil can be direct seeded or transplanted to the field. For direct seeding, seeds are spaced only 3 to 6 mm deep at a spacing of 5 cm apart.
Basil is mainly propagated from seeds. Basil can also be propagated from cuttings with the stems of short cuttings suspended for two weeks or so in water until roots develop.
Fertilizer applications depend on the soil type, previous crop and fertilizer applications for the previous crop. Most importantly the recommendations should be dependent on the soil analysis results. Basil responds well to soils of a moderate fertility.
Basil has to be irrigated regularly throughout the growing season in order to maintain constant growth, if rainfall is not enough. Basil may be irrigated with sprinklers, however, drip irrigation is a better option.
Cultivation practices such as high plant populations, shallow cultivation, decreasing row spacing and mulching can be practiced to keep weed populations low.
Mechanical cultivation and manual weeding are some of the weed control methods that can be used. Preventative measures include: choosing a cultivar that has rapid seed germination and plant growth; using certified crop seeds that are weed free; using weed-free mulch and cleaning of equipment before use.
Pest and disease control
Basil naturally attract chewing type pests such as beetles, slugs, leafminers, caterpillars and grasshoppers; and sucking type such as leaf hoppers, thrips and whitefly.
Fungal, bacterial and nematode diseases occur more frequently in basil. The normal disease and pest control guidelines should be followed for the control of these diseases and pests.
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