Ocimum gratissimum aka African Basil

Ocimum gratissimum thrives in warm temperatures between 70-95°F (21-35°C) and does not tolerate frost. The plant grows naturally in subtropical to tropical climates with annual temperature ranges of 17-25°C lows and 27-36°C highs. In colder regions, it must be brought indoors or grown in a greenhouse during winter, or cultivated as an annual.

Apply a balanced fertilizer with a 5-10-5 (N-P-K) ratio every 4-6 weeks during the growing season, or use organic compost every 1-2 months. Research shows that Ocimum gratissimum is sensitive to nitrogen levels and responds well to adequate nitrogen supplementation, particularly for essential oil production. For intensive cultivation, nitrogen doses higher than normally recommended can improve growth and oil content.

Ocimum gratissimum has an intense aromatic fragrance that varies by chemotype. The most common forms have a strong clove scent (eugenol chemotype) or a thyme-like aroma (thymol chemotype), with some varieties showing hints of lemon-thyme or citral. All plant parts are strongly scented, making it popular for culinary use, essential oil production, and as an insect repellent.

Yes, Ocimum gratissimum produces small white to pale pink flowers on tall spikes during summer to early fall, with year-round flowering possible in tropical climates. Flowering typically occurs around 136 days after germination. The flowers attract pollinators including bees, butterflies, and moths. Many growers remove flower spikes to prolong the plant's productive life and encourage continued leaf production.

Ocimum gratissimum has at least six distinct chemotypes characterized by their essential oil composition: eugenol (most economically important, 40-95%), thymol, citral, ethyl cinnamate, geraniol, and linalool. The eugenol and thymol types are the most common, historically classified as O. gratissimum forma caryophyllatum and forma graveolens respectively. These chemotypes differ in fragrance and flavor, ranging from clove-like to thyme-like aromas.

Ocimum gratissimum grows best outdoors in USDA hardiness zones 10-11 where it can be cultivated as a perennial shrub. In colder regions (zones 5-9), it must be grown as an annual or overwintered indoors, as it is not frost-hardy. The plant thrives in sub-humid to moderately humid subtropical and tropical climates with annual rainfall of 700-2000mm and requires full sun exposure with 6-8 hours of direct sunlight daily.

Prune Ocimum gratissimum regularly throughout the growing season to maintain shape and encourage bushier growth. Remove dead or yellowing leaves and trim back leggy stems. Harvest by cutting stems above lateral nodes to promote side shoot development. For optimal essential oil content, harvest when the plant reaches 15cm tall or when 75% of branches start flowering. Remove flower spikes as they appear to prolong the plant's productive life and concentrate energy on leaf production.

Repot Ocimum gratissimum every 1-2 years or when it outgrows its current container. Choose a pot at least 20cm (8 inches) in diameter with good drainage holes, using well-draining potting mix rich in organic matter. For container cultivation, use pots of 5-12 liters (1.5-3 gallons) to accommodate the plant's root system. The best time to repot is in spring before active growth begins.

Ocimum gratissimum is usually propagated from woody stem cuttings, as this method is more reliable than seeds which have very low germination rates (below 10%). For cuttings, take healthy stems from mature plants and root in water or soil - roots develop within approximately 28 days. Seeds can be sown uncovered in well-drained, moist soil at 20-25°C and need strong sunlight to germinate, taking 8-10 days with sowing to flowering occurring in 60-90 days.

Ocimum gratissimum is relatively pest-resistant but may be affected by aphids, spider mites, whiteflies, and occasionally caterpillars. Fungal diseases including powdery mildew and downy mildew can occur in overly humid conditions or with poor air circulation. Prevention includes proper plant spacing, avoiding overwatering, ensuring good drainage, and maintaining adequate air circulation. Inspect plants regularly and use organic pest control methods when needed.

Ocimum gratissimum is pollinated by insects (entomophilous pollination) and attracts diverse pollinators including honeybees, butterflies, moths, and flies. The plant provides essential nectar and pollen and flowers profusely, making it excellent for bringing pollinators to the garden. While primarily cross-pollinated by insects, the plant likely has a mixed breeding system capable of both cross-pollination and some self-pollination.

Yes, Ocimum gratissimum is edible with leaves, flowers, and seeds all being consumed. The leaves can be used fresh or dried as a culinary herb with clove or thyme flavor, cooked as a potherb (alone or mixed with other vegetables), or infused for tea. The delicate flowers add flavor to salads, and seeds are occasionally consumed in India. The lemon-thyme flavored varieties are particularly suited for salads and seasonings.

Ocimum gratissimum is used in traditional medicine as an aromatic, stimulant, antispasmodic, and antiseptic herb. It treats colds, influenza, fevers, headaches, flatulence, diarrhea, parasitic infections, and respiratory problems internally, while externally it addresses rheumatism and lumbago. Research has demonstrated antimicrobial, antioxidant, anti-inflammatory, cardiovascular, glucose-lowering, antifungal, and hepatoprotective activities in vitro and animal models, though clinical data in humans is lacking.

Beyond culinary and medicinal applications, Ocimum gratissimum serves multiple purposes. The essential oil (0.8-1.2% yield) is used in perfumery and mosquito repellent formulations. The plant effectively repels insects and is valued for this property. Peeled twigs serve as traditional chewing sticks for oral hygiene in some cultures. It is sometimes cultivated as hedging and is an excellent pollinator plant for gardens.