Basil

Family

Lamiaceae

Habit

perennial

Height

0.5 m

Spread

0.3 m

Growth

very fast

Lifespan

2 years

First yield

after 1 year

Hardiness

zone 10–11

Shade tolerance

full sun

Soil

Sand, Silt

Soil moisture

semi-dry – moist

pH

5.3 – 8.6

Times apply to the northern hemisphere in a temperate climate and shift with altitude and cultivar.

Edible: What is used are the leaves, fresh as well as dried, though drying brings marked losses of aroma. Basil is one of the most used herbs in southern European and especially Italian cooking: it is almost always part of pesto and indispensable for the traditional Neapolitan pizza, and its fine aroma goes outstandingly well with tomatoes. Because the aroma is heat-sensitive, the leaves are added at the end rather than cooked. Beyond the home kitchen basil is used in the meat canning industry, and basil macerate and distillate are components of some herbal liqueurs. The flowers are edible and make a good garnish. A more recent use concerns the seeds: soaked basil seeds are used in drinks much like Mexican chia; otherwise they are unusual as a food.

Other uses: The non-culinary use of basil lies almost entirely in the essential oil. It is employed in the cosmetics industry for fragrance blends and generally as a flavouring; the meat canning industry uses basil in that role too. Macerate and distillate of the leaves go into herbal liqueurs. Widespread but undocumented is its use as an insect repellent: a pot of basil on the windowsill or the terrace table is supposed to keep mosquitoes and flies away — the idea is old and found in many countries, but no reliable effect has been demonstrated. The same applies to companion planting with tomatoes: it makes sense because of their shared need for warmth and water, but no plant-protecting effect has been shown.

Site: Basil is above all a question of warmth. Below 12 degrees there is practically no growth while fungal attack rises sharply — basil planted too early stands still for weeks and then fails. The position should be warm, sheltered and sunny; in high summer light midday shade suits it better than full glare. The soil must be loose, free-draining and quick to warm, with a pH ideally between 6.5 and 7.2. In the vegetable bed a spot beside the tomatoes is the obvious choice, since both want the same warmth. Two things follow: slugs are the main enemy in damp, shaded places, and flowering basil is a good bee plant but loses much of its leaf aroma — if you want both, plant two groups, one for picking and one for flowering. Basil is frost-sensitive and grown as an annual in Central Europe. Care: The key operation is regular pinching out: cut whole shoot tips above a pair of leaves, never individual leaves — this promotes bushy growth and delays flowering. Water evenly moist but not wet, in the morning and preferably not over the foliage, since leaf spot caused by Septoria species appears in wet periods. Further problems are Fusarium wilt both outdoors and under glass and the aphid-borne alfalfa mosaic virus, which causes leaf yellowing; among animal pests, leafhoppers, knot grass moth caterpillars, tarnished plant bugs and slugs feed on the foliage. A note on shop-bought pots: these are densely sown greenhouse seedlings, not intended as house plants — to keep them, separate the plants and repot them with room for the roots, and only outdoors will they develop robustness. Harvest before the first cold nights in autumn.

Basil is easy to propagate in two ways. The classic route is sowing from March on a windowsill: basil needs light to germinate, so the seed is only pressed in and not covered, germinates at 20 to 25 degrees within one to two weeks and is grown on individually after pricking out. Sow directly outdoors only once the soil is reliably above 12 degrees — before that it germinates reluctantly and rots easily. The second route is even simpler and the most convenient for households: cut shoots placed in a glass of water form roots within a few weeks and can then be potted up. Because cultivars cross readily from seed, cuttings are also the true-to-type way of keeping a particular plant. Seed ripens in late summer and stays viable for several years.

Basil is usually harvested before it flowers and therefore drops out entirely as an insect plant — that is a gardener's decision, not a property of the plant. Let some shoots flower and the small white labiate flowers are a good source of nectar and pollen for weeks, well taken by honeybees, bumblebees and wild bees; the high nectar and pollen values in the database reflect this. Reliable species counts for Central Europe do not exist and hardly can: basil here is an annual, frost-sensitive crop without its own associated fauna. The only documented herbivores are generalists that show up as pests in cultivation — knot grass moth caterpillars (Acronicta rumicis), leafhoppers, tarnished plant bugs and slugs. The plant has no structural or bird value. The practical advice is therefore simple: a few plants to harvest, a few left to flower.

Notable: the name comes via Latin basilicum from Greek basilikon, "royal"; cultivated in north-western India as a culinary, medicinal and ornamental plant as early as 1000 BC, with pyramid finds documenting cultivation in ancient Egypt; it reached Germany only in the 12th century; numerous folk tales about its origin survive in Greece to this day; not to be confused with Indian tulsi (Ocimum tenuiflorum), a separate and religiously venerated species;

Tropical to subtropical Asia, probably north-west India. The origin of basil can no longer be established with certainty; north-west India is the assumed home region, and some sources give subtropical to tropical Asia generally as its natural range. In north-western India it was already cultivated around 1000 BC as a culinary, medicinal and ornamental plant, and finds in pyramids document its cultivation in ancient Egypt. It probably reached Germany in the 12th century. Today it is grown worldwide, mostly in subtropical regions but also in the tropics and in temperate zones, outdoors as well as under glass. In Germany field-grown basil reaches the market from about late June to early October, greenhouse stock all year round.

Basil has no habitat in Central Europe: it is a frost-sensitive crop plant that occurs here only in beds, pots and greenhouses and disappears over winter. Even for its region of origin no natural habitat can be named precisely any more, because the species has been in cultivation for over three thousand years and its wild occurrences can no longer be separated reliably from escapes. What can be inferred from its requirements: it is adapted to warm, summer-moist conditions, demands loose, free-draining, quickly warming soils in the neutral range, and stops growing below 12 degrees. That corresponds to open, warm sites in tropical and subtropical lowlands with a moist growing season, not to closed forest and not to permanently arid regions.