Itinerário técnico
Um guia de cultivo passo a passo, da sementeira à colheita.
Sow direct half a centimetre to one centimetre deep, or in trays for transplanting at four or five weeks. Germination takes seven to fourteen days with the soil between 15 °C and 22 °C. Sow every three weeks, because these plants flower quickly and the leaf loses quality once flowering starts. A single sowing is the commonest mistake: you end up with a glut and then nothing for the rest of the season.
It adapts to ordinary soils as long as they are loose and free draining, at a pH between 6.0 and 7.5. Over rich soil gives large watery leaves with far less aroma. Essential oil concentration is higher in average soils with a degree of water restraint.
It prefers full sun to part shade and temperatures between 15 °C and 22 °C. Strong heat speeds up flowering and cuts the leaf harvest; part shade over the middle of the day greatly extends the cycle in an Iberian summer. It adapts to most of western Europe. On the Portuguese coast and in southern Spain use spring and autumn and avoid the peak of summer. Inland in Iberia water more through the dry months. In France and Germany the natural season is spring and summer, sowing once the soil has warmed steadily. In Italy the same rule applies as in the rest of the Mediterranean: spring and autumn in the centre and south, spring and summer in the north.
It asks for little and an over rich soil works against it. Soil that was composted for the previous crop is enough, with no extra feeding. Excess nitrogen gives soft, watery growth with little flavour and much greater sensitivity to pests and cold.
Water regularly without waterlogging, keeping the soil slightly moist. Water shortage brings flowering forward and toughens the leaf. Water in the morning at the base, so the foliage dries through the day.
Hoe often and always shallowly, because the roots are short, near the surface and break easily. The best method is to prepare the bed two or three weeks in advance, let the first flush of weeds germinate, remove it and only then sow: that gives you a decisive head start. A thin layer of sieved compost between the rows greatly reduces later work.
Pests are few because the plant's aroma keeps many insects away. Aphids are the commonest problem and gather on the soft shoots, above all on over fed plants: cut off the affected tips and apply potassium soap. Red spider mite appears in dry heat and in pots, and is checked by wetting the foliage in the morning. Slugs and snails devastate seedlings: protect with an ash barrier in the first weeks. Thrips and leafhoppers are occasional and rarely need action.
Downy and powdery mildew appear in humid conditions with no airflow, and collar rot in waterlogged soil. Sow with enough space, water at the base and avoid wetting the foliage in the afternoon. Remove any plant showing disease at once, because in dense sowings it spreads within days.
Pick the tips often, cutting above a pair of leaves, which makes the plant branch and produce more. Never take more than a third of the plant at once. Cut off flower stems as soon as they appear if you want to keep harvesting leaves. The aroma is strongest in the morning, once the dew has dried and before the sun gets strong. Allow about 50 to 60 days from transplanting to the first harvest of this variety. The reference colour is blue or lilac flower, and that is what tells you it is ready.
