Itinerário técnico
Um guia de cultivo passo a passo, da sementeira à colheita.
Sow in trays one or two centimetres deep at 20 °C to 25 °C, eight to ten weeks before transplanting. Germination takes two to three weeks. Transplant at four to six true leaves, giving plenty of room, because the plant occupies more than a square metre. It is perennial and produces for four to six years in the same place. Seed raised plants are variable, which is part of the interest.
It wants deep, fertile and very free draining soil at a pH between 6.5 and 7.5. Being perennial, prepare the site well with mature compost before planting, because it will be there for years. Standing winter moisture is the main cause of plant death.
It is a Mediterranean plant wanting full sun and mild winters, between 15 °C and 25 °C. Frost below minus five degrees damages the crown: in France and Germany protect the base with a thick layer of straw or leaves in winter. On the Portuguese coast and in southern Spain it grows practically all year. It is in its element in a Mediterranean climate: full sun, heat and dry soil. On the Portuguese coast it grows well, but the humid air and fog call for a raised bed and generous spacing. Inland in Portugal and Spain it is close to self-sufficient once established. In France it grows easily south of the Loire, and in Germany the problem is not dry cold but the wet winter, which rots the roots: plant in very free draining soil, in a pot or on a slope, and shelter it from winter rain. The same calendar applies in Italy: conditions in the centre and south are close to those of southern Portugal and Spain, and those of the north to central France.
This is a hungry crop. Work two to three kilos of well rotted compost or mature manure into each square metre before planting and add a handful of bone meal or wood ash to top up phosphorus and potassium. Once growth is away, feed with a liquid organic fertiliser every two or three weeks, moving from a balanced formula to a higher potassium one as cropping begins. Avoid excess nitrogen, which gives lush leaves, a poor crop and a lot of aphids.
Water regularly during growth and head formation, because water shortage gives small tough heads. Cut right back in summer, when the plant goes dormant, and stop almost entirely in winter so the crown does not rot.
Hand weed in the first weeks, while the plant is small and loses every contest for light and water. Once it is established, mulch with five to seven centimetres of straw, dried grass or leaves: it holds weeds back, keeps moisture in and stops rain splashing soil onto the lower leaves, which is how most diseases begin. Always hoe shallowly so you do not cut the roots running just under the surface.
Aphids swarm the heads and young leaves in spring and are the decisive pest: wash them off with a jet of water, apply potassium soap and encourage ladybirds. Slugs and snails hide between the bracts. Artichoke borer tunnels the stem and heads and forces you to cut out the affected parts.
Powdery mildew covers the leaves with white bloom and botrytis rots the heads in damp weather. Verticillium wilt and root rot kill the plant in heavy waterlogged soil and cannot be treated. Remove old leaves every year and do not plant where artichoke or cardoon has grown recently.
Cut the heads while still tightly closed and firm, with ten centimetres of stem. A head whose bracts are starting to open has already gone fibrous. Take the central head first, the largest, then the side ones, which come on over several weeks. Cut the plant down at ground level after cropping to force fresh growth. Allow about 365 days from transplanting to the first harvest of this variety. The reference colour is purple, and that is what tells you it is ready.
