Itinerário técnico
Um guia de cultivo passo a passo, da sementeira à colheita.
Always sow direct and never transplant, half a centimetre to one centimetre deep at most, in rows. Germination is slow, fourteen to twenty one days, and demands that the soil surface stays moist throughout: letting it dry out just once is the commonest cause of failure. Cover the row with a board or damp cloth until it emerges. Thin in two passes, out to five or eight centimetres between plants.
It wants sandy or loamy soil, deep, loose, free of stones and clods, at a pH between 6.0 and 7.0. Any obstacle makes the root fork. No fresh manure and no coarse compost, which cause forked hairy roots. In heavy soil, grow short varieties or use a raised bed with sieved soil.
It prefers temperatures between 15 °C and 22 °C. Colour and sugar develop best with cool nights, which makes autumn harvests the tastiest. It takes light frost and in the south can stay in the ground through winter. 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.
Do not use fresh manure or strong nitrogen feeding: that gives forked, hairy and tasteless roots. Use a bed that was composted for the previous crop and top up potassium only, with sieved wood ash, which improves sweetness and keeping quality.
Keep moisture constant and even. Long gaps followed by heavy watering split the roots down the middle, which is the commonest defect. Water little and often until germination, then more deeply and less frequently so the root goes down.
The crop germinates slowly and is completely overrun by weeds in the first weeks, which is the number one cause of failure. Prepare the bed in advance, clear the first flush of weeds before sowing and mark the row with radish, which comes up within days and shows you where to hoe. Hoe shallowly between the rows and never pile soil over the crown.
Carrot fly is the decisive pest: the female finds the crop by the smell released when you thin, and the larvae tunnel brown galleries through the root. Thin at the end of the day, take the pulled plants away from the site at once and cover the crop with fine mesh sixty centimetres high, because the fly flies low. Sowing next to onion or leek confuses it and helps. Also watch for aphids and nematodes in infested soil.
Alternaria makes dark leaf spots and weakens the plant in damp weather. Powdery mildew shows late in the cycle. Root rot appears in waterlogged soil and sclerotinia attacks stored roots. Rotate on a three to four year cycle away from other umbellifers such as parsley, celery, fennel and parsnip.
Lift when the shoulder of the root shows at the surface at the typical diameter for the variety, or pull one to check. Water before lifting so the soil releases. Cut the tops off immediately after harvest, leaving one centimetre, because the leaves keep drawing water from the root and make it go limp. It keeps for months in damp cool sand. Allow about 130 days from sowing to the first harvest of this variety. The reference colour is orange, and that is what tells you it is ready.
