Basil

Origin & history

Basil comes from the tropics of South and South-East Asia and has been cultivated in India for thousands of years. It travelled by way of the Near East to Greece — the name goes back to the Greek basilikón, “royal” — and with the Romans north of the Alps, where for centuries it remained a pot herb on the windowsill. Its identification with Italian cooking is younger than you would think: the first printed recipe for pesto alla genovese appears in a Genoese cookbook of 1863.

Varieties

Large-leaved Genovese basil is the classic for pesto; Greek bush basil stays small-leaved and compact and copes far better in a pot, while Thai basil brings an aniseed note and takes heat better than any of them. Red-leaved varieties grow more slowly and taste stronger. The supermarket pot, incidentally, is not one plant but thirty or forty seedlings sown far too thickly — if you want to keep it, split the rootball into three or four portions and pot them on separately into larger pots.

Care

Warmth is everything: below about ten degrees at night basil stops growing and turns yellow, so plant it out only after the Ice Saints, in a sunny spot sheltered from wind. Water in the morning and always at the base, never over the foliage and never into a saucer of standing water — wet feet plus a cold night cost more plants than any pest. Pinch out flower buds as soon as they appear, or the plant stops making leaves.

What can go wrong

Sown too thickly into compost kept too wet, the seedlings kink over just above the soil; sowing thinly, keeping the compost merely damp and airing it daily is the whole of the prevention. Basil downy mildew is now widespread: a grey-brown coating on the leaf undersides and pale patches between the veins — an airy position, watering in the morning at the base and explicitly resistant Genovese varieties are what helps. Young plants are also a favourite of slugs: plant out well-grown plants rather than small seedlings, and collect them in the evening.

Harvest, storage & kitchen

Basil goes into the dish right at the end — cooked along with everything else, nothing of the aroma survives. Cut the leaves in the kitchen with a sharp knife or tear them by hand; bruised cut edges go black within minutes. Drying is not worth it, since almost all the flavour is lost; better to freeze it chopped, put it up in oil or turn it straight into pesto. Stand a bought bunch in a glass of water at room temperature, not in the fridge — there the leaves blacken.

Frequently asked questions

When can I plant basil outdoors?

Between 20 May and 20 June, once the nights stay reliably mild. Raise it indoors from March, about five weeks before planting out. Harden bought pots off over a week in a few hours of sun at a time, or the leaves scorch into pale patches.

Is basil winter hardy?

No. Basil is frost-tender and takes damage at a few degrees above freezing, long before the first real frost. It is an annual, so you sow again each spring from March; a pot brought indoors usually lasts only a few more weeks.

Why is my basil flowering?

Heat, drought, a cramped pot and simply the age of the plant all set off flowering. The leaves stay edible but turn smaller and sharper in taste, and the white flowers can be used as well. Letting one shoot flower gives you your own seed in autumn.

Does basil grow on a windowsill?

Yes, in a pot of about 15 centimetres at the brightest window you have. Light decides it: from November to February most flats simply do not have enough, and the shoots stay long and pale. Right above a radiator it dries out faster than you can water it.