African basil leaves

Names and species boundaries

Kew accepts Ocimum gratissimum L. and gives its native range as tropical and subtropical parts of the Old World. The RHS lists East Indian basil, fever plant and tree basil among its common names, and includes Ocimum basilicum “Tree” in its synonym field. Benin’s INRAB guide identifies Tchiayo as O. gratissimum; JIRCAS lists Thai names including Yeera and kaprao yuan. These local labels and profile entries describe source contexts; they do not identify an unlabeled plant or settle cultivar identity.

Food use in three regional accounts

A Benin technical report describes Tchiayo leaves cooked in a tomato-based sauce and dried, pounded leaves used in sauces served with pounded yam. JIRCAS describes Thai leaves fried with hot chili and minced garlic, or with meat, as a flavouring. A southern Nigerian study abstract reports Igbo use of scent leaf to flavour soups and stews; only its abstract was inspected. These reports show different regional uses rather than one pan-African recipe.

Growing reports

The Benin guide describes seed propagation through a nursery: sowing, regular watering, shade after emergence and transplanting to field beds. It reports year-round cultivation, with stronger production in rainy seasons and regular water needed in the dry season. JIRCAS describes direct seeding, full sun, well-drained soil with sufficient moisture, 50 × 75 cm transplant spacing and leaf harvest about two months after transplant in Thailand. The RHS assigns H1B under its UK scheme, recommending summer outdoor growing and under-glass conditions otherwise; it gives no measured frost-survival cutoff. These are regional observations, not a combined universal schedule.

A Benin sauce report, with limits

The 2015 INRAB report names a Tchiayo sauce with tomato, palm oil, fish, shrimp and seasonings. Its method includes boiling the leaves with potash or bicarbonate, but it does not state the alkali amount; several seasoning quantities and the final cooking endpoint are also unclear. This account is useful food context, not a complete household formula or a basis for inventing a safe alkali dose.

Harvest, storage and crop problems

Benin reports describe repeated cutting and leaf regrowth; JIRCAS gives a Thai harvest interval of about two months after transplant. The 2019 Benin guide contains an internally inconsistent numeral for its first harvest interval, so no exact value is repeated here. The 2015 report says fresh leaves were kept for up to three days using a damp-cloth approach, but it gives no validated storage-safety basis or dried-leaf endpoint. Benin sources report aphids, whiteflies, caterpillars and other crop pests; the RHS separately lists possible glasshouse pests and grey mould.

What remains unresolved

The sources do not establish a household pot size, greenhouse setpoint, universal frost or heat limit, or one cultivation calendar for different climates. The reported sauce lacks ingredient detail and a complete endpoint, while postharvest reports do not validate a safe storage life. No claim about medicinal benefit, essential-oil use or plant identification is made here.

Research gaps

The Benin sauce report omits the potash/bicarbonate amount, several seasonings and a complete endpoint; it is not presented as a recipe.

No household mature-container or controlled greenhouse protocol was found. RHS H1B is a UK profile category, not a measured survival threshold.

Benin seed and RHS cutting propagation describe different source contexts; no comparative trial establishes that either method is impossible elsewhere.

The reported fresh-leaf storage practice and duration are not validated food-safety limits.

The Nigerian paper was inspected only as an abstract; no early culinary attestation or global use pattern is claimed.

Research status

The underlying plant account received a source review. Its review scope is described in the original plant article.