Itinerário técnico
Um guia de cultivo passo a passo, da sementeira à colheita.
Sow direct four to six centimetres deep in rows. Germination takes seven to fourteen days. In southern Europe sow in late winter or early spring; further north, once the soil has warmed well. Do not transplant. It is a dryland crop above all and dislikes excess moisture at any stage.
It prefers light, chalky and very free draining soils and tolerates pH up to 8.0. It puts up with poor ground better than almost any other crop. Never in heavy waterlogged soil, where the roots rot quickly.
It likes heat and dryness, between 18 °C and 28 °C, and is one of the most drought resistant crops in the garden. It stands light frost when young. Excess humidity at flowering and ripening is its worst enemy, which makes the humid Atlantic coast the least favourable area. On the Portuguese coast the crop starts slowly because nights stay cool and morning fog keeps the leaves wet for hours, so pick the sunniest spot you have, shelter it from wind and space the plants generously so air moves through. Inland in Portugal and Spain heat rather than cold is the limiting factor: in weeks above 35 °C the plant stalls and light shade over midday pays for itself. In France outdoor growing is reliable from the centre southwards, while in northern France and in Germany a greenhouse, a polytunnel or a warm south facing wall makes the difference, and planting out should wait until after the mid May cold snap. Where summers are short, always choose the shorter cycle varieties and start them early in a heated tray. In Italy it is an easy crop: in the centre and south plant from April onwards and the only real care is light shade through the July and August heat; in the Po valley and the north wait for the late frosts to pass and pick the sunniest spot you have.
It fixes its own nitrogen through root nodule bacteria, so it should not be given nitrogen fertiliser. Add mature compost only if the soil is poor and, if needed, a little wood ash for potassium. Feeding nitrogen is the classic mistake with this crop: it produces huge plants with few pods.
It needs practically no irrigation in a Mediterranean climate. One supporting watering at flowering, in a very dry year, improves yield. Excess water gives plenty of leaf, few pods and root rot.
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.
Pod borer caterpillars bore into the seeds while still on the plant and are the main pest: apply Bacillus thuringiensis at flowering if you find eggs. Aphids attack the soft tips. Weevils drill into stored seed: freeze it for forty eight hours before storing.
Ascochyta blight makes dark spots with black specks on leaves and pods in wet springs and can destroy the crop: use clean seed, sow with wide spacing and do not work among wet plants. Fusarium wilt kills plants in infested soil. Use a four year rotation.
For green use, pick the pods when full and still green. For dry grain, wait for the plant to yellow and the pods to dry completely, pull whole plants and let them dry a few days more before threshing. Harvesting damp is the mistake that rots stored grain. The reference colour is cream, and that is what tells you it is ready.
