Basil

Basil is not hardy and dies at temperatures below about 10 °C. You do not overwinter the usual annual Genoese basil, but simply raise it anew from seed in spring. Only perennial shrub varieties (e.g. African Blue) can be carried through: pot them up before the first frost and put them indoors in a bright, frost-free spot at around 10 to 15 °C, watering much less.

Basil can be propagated in three ways, with sowing and cuttings being the most important.

Sowing (March to May): Basil is a light germinator. Only press the seeds down lightly; do not cover them with soil. Keep the germination temperature between 20 and 25 °C, and the seeds will usually germinate in 1 to 2 weeks. You can start on the windowsill from late March; for direct sowing outdoors, wait until mid-May (week 20), when there is no longer any risk of frost. From your own saved seed, pure varieties grow true to type, whereas F1 hybrids do not.

Cuttings (spring to summer): Cut a healthy, flower-free shoot 10 to 15 cm long directly below a pair of leaves. Remove the lower leaves so that only 2 to 3 pairs of leaves remain at the top. You can stand the cutting in water (a bright but not blazing sunny spot, around 20 to 24 °C) and change the water every two to three days. After about 1 to 2 weeks the first roots appear. Alternatively, insert it directly into slightly moist seed compost. Cuttings come true to type and give plants ready to harvest sooner than sowing.

Division: Supermarket pots often contain many seedlings packed tightly together, competing for water, light and nutrients. Carefully ease the root ball out and divide it into three or four portions of equal size. Moisten the root ball beforehand so that you can gently pull the roots apart. Each piece goes into its own pot with fresh soil. This way you avoid the early collapse of overcrowded pots and raise several strong plants from one pot.