Um guia de cultivo passo a passo, da sementeira à colheita.
pH ideal 6.0 to 6.8Temperatura ideal 20 to 28 °CCompasso 45 to 60 cm in the row, 90 to 120 cm between rows
Sementeira
Sow in trays six to eight weeks before the intended planting date, half a centimetre deep, in a light compost at 20 °C to 25 °C. Germination takes five to ten days. Prick out into individual pots once the first true leaves show and bury the stem up to the seed leaves, because it roots along its length and gains anchorage. Harden the plants off outdoors for a week before planting out. Only plant out once the soil holds 15 °C steadily and frost risk has passed. This is an indeterminate variety: the plant keeps extending all season and can pass two metres. It absolutely needs a stake, cane or training string from transplanting, plus weekly side shooting, removing the shoots that appear between stem and leaf while they are still small. Without training it becomes a mass of foliage on the ground that rots and picks up disease. Keep the plant to one or two stems and pinch out the top at the end of summer, about thirty days before the first expected frost, so the last trusses ripen.
Solo
It wants deep, fertile, free draining soil rich in organic matter, with a pH between 6.0 and 6.8. Work the ground to at least 30 centimetres because the roots go down looking for water. Soil with good calcium levels prevents blossom end rot, the commonest tomato defect. Do not follow tomato, potato, pepper or aubergine in the same bed for three or four years.
Clima
It needs full sun, at least six to eight hours a day, and temperatures between 20 °C and 28 °C. Below 12 °C at night the flowers do not set and above 35 °C the pollen goes sterile, so there is always a gap in fruit set at the height of summer. 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.
Fertilização
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.
Rega
Water deeply and regularly, always at the base of the plant and never over the leaves. Regularity is everything: swinging between dry and waterlogged is the direct cause of blossom end rot and split fruit. One generous watering two or three times a week beats a little every day. Drip irrigation under a straw mulch is the ideal set up. Inland in Iberia, at the peak of the heat, daily watering may be needed.
Controlo de Infestantes
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.
Controlo de Pragas
The main pests are aphids, whitefly, red spider mite, thrips and tomato caterpillars. Against aphids and whitefly use potassium soap at the end of the day and encourage ladybirds and lacewings with flower strips nearby. Mite arrives in dry heat: raising air humidity and using neem oil holds it back. Against caterpillars apply Bacillus thuringiensis while they are still small. Yellow sticky traps help you spot whitefly early. Root knot nematode is a problem in warm sandy soils and is handled with long rotations and plenty of organic matter.
Doenças
Late blight is the disease to fear and strikes in cool damp weather, above all on the Atlantic coast and in northern Europe: oily brown patches appear on leaves and fruit. Prevent it with wide spacing, removal of the lower leaves up to 30 centimetres from the ground, watering at the base and a straw mulch. Powdery mildew, a white dust on the leaf, comes with dry heat and is checked with sulphur or potassium bicarbonate. Early blight makes concentric rings on older leaves. Blossom end rot, the black patch at the base of the fruit, is not a disease but calcium shortage caused by uneven watering. Remove and destroy diseased leaves and never put them in the compost heap.
Colheita
Pick when the fruit has reached its final colour and gives slightly under finger pressure, ideally in the morning. Cut with a short piece of stalk rather than pulling, so you do not tear the plant. Never keep tomatoes in the fridge: below 12 °C they lose aroma irreversibly. If rain or cold arrive at the end of the season, pick the fruit that has started to colour and let it ripen indoors. The reference colour is red and green, and that is what tells you it is ready.
