TomatoSolanum lycopersicum

The tomato wants at least six hours of direct sun a day and, in our climate, shelter from rain makes all the difference. The best position is a cold greenhouse, a polytunnel or a simple transparent canopy against a south- or south-west-facing wall, which gives back heat at night. Avoid wind corridors and the bottom of the garden where cold air settles in the early morning. Do not replant in the same spot two years running, nor after potatoes, so as not to keep blight alive in the soil. Plan for access: you will be visiting your plants every two or three days.

From autumn or by March at the latest, loosen the bed with a broadfork to twenty-five centimetres without turning the layers, then work three to five kilos of mature compost per square metre into the surface. In heavy Belgian clay, add a bucket of coarse sand or leaf mould to improve drainage. A winter mulch, removed a fortnight before planting, lets the soil warm up. Never use fresh manure: it burns the roots and attracts disease. A handful of sieved wood ash per plant provides the potash that colours and sweetens the fruit.

Without a grow lamp, do not sow before mid-March: in February the light from our windows is too weak and the plants become leggy, pale and fragile. A sowing between 10 and 25 March, behind a south-facing window or under an LED strip placed ten centimetres above the leaves, gives stocky plants just in time for mid-May. Choose two or three complementary varieties: an early cherry, a sauce tomato, a large beefsteak type. Label every pot, as the seedlings all look alike. Turn the pots a quarter turn each day to stop the stems leaning.

A good plant measures twenty to thirty centimetres, has a stem as thick as a pencil and sometimes its first flower truss. For seven to ten days, put it outside during the day and bring it in at night so that it hardens off. Plant in the evening or in overcast weather, in a twenty-centimetre hole enriched with a handful of compost. Remove the lower leaves and lay the plant at an angle or bury the stem up to the first leaves: every hair becomes a root. Water with at least three litres, then wait a few days before watering again to force the roots downwards.

On a balcony, the tomato does very well provided you give it a container of at least twenty litres per plant, thirty for a vigorous variety, with drainage holes and raised on blocks. Fill with a mix of two thirds good-quality potting compost and one third garden compost, with a layer of clay pebbles or gravel at the bottom. Dwarf or determinate varieties, such as balcony cherry tomatoes, make do with a more modest pot and a short stake. In pots, the compost dries out quickly: expect to water daily in July, and give a liquid feed every fortnight from flowering.

Planting in early May because the weather is fine: a single night at 3 °C sets a plant back three weeks. Cramming plants thirty centimetres apart: the foliage stays damp, blight moves in and the fruit lacks light. Putting the stake in after planting: you pierce the roots. Watering a little every evening rather than generously once or twice a week: the roots stay near the surface and suffer at the first heat. Sowing too early without enough light, forgetting to label, or wanting twenty plants in your first year when six well-tended plants feed a family.

The tomato prefers infrequent but abundant watering: outdoors, five to ten litres per plant once a week, twice in a heatwave, applied slowly at the base so the water soaks down. A buried terracotta pot or an upturned bottle near the stem directs water to the roots. Water in the morning by preference, never on the leaves, and do not let the soil swing between drought and sodden: that is what causes blossom end rot and split fruit. In late summer, gradually reduce watering, which concentrates the sugars. In a greenhouse, water at room temperature is better tolerated.

Once the soil has warmed through, around early June, spread eight to ten centimetres of straw, dried grass clippings or hay around the plants, without touching the stem. This mulch keeps the soil cool, prevents the splashes that spread blight and feeds the earthworms. As for feeding, the tomato mainly needs potash from flowering onwards: comfrey liquid diluted to 10 %, every fortnight, or an organic tomato feed. Too much nitrogen gives lush foliage and few fruits. Comfrey leaves laid under the mulch break down and release their minerals slowly.

Tie the stem to the stake every twenty centimetres, with a soft tie in a figure of eight that leaves room to thicken. On indeterminate varieties, remove every week the side shoots that appear in the leaf axils, when they are three to five centimetres long, pinching them cleanly between two fingernails in dry weather. Training to a single stem gives larger, earlier fruit; two stems increase the quantity. Cherry and determinate varieties need little pruning. Around mid-August outdoors, late August in a greenhouse, cut off the top above the fifth or sixth truss: any later fruit would not have time to ripen.

Blight remains enemy number one in our damp summers. Ventilate as much as possible, space the plants out, remove the lower leaves up to the first truss and keep the foliage dry. In stormy weather, spray a horsetail decoction or bicarbonate of soda at 5 g per litre with a drop of soft soap, every ten days. In a greenhouse, open doors and vents from the morning onwards. Against aphids, soft soap diluted to 5 % and French marigolds between the plants. Tomato moth caterpillars are picked off by hand in the evening. Disinfect secateurs and stakes from one season to the next.

March: sowing in warmth and pricking out into pots. April: gradual hardening off, preparing the bed. Mid-May: planting out, staking, first generous watering. June: mulching, first tie, start of side-shoot removal, removal of lower leaves. July: weekly watering, comfrey liquid every fortnight, watching for blight after every storm. August: topping, light defoliation around the trusses to expose them to the sun, reduced watering. September: peak harvest, removal of new flowers. October: harvest of green fruit before the frosts, pulling up the plants and disposing of the haulms away from the compost heap.

Pick in the morning, at full colour, when the fruit comes away easily with a twist. A tomato picked just as it turns, barely blushing, ripens in the kitchen without losing flavour, which relieves the plant and avoids splitting after a storm. In a greenhouse, the harvest often continues until All Saints' Day if you close up in the evening and keep the foliage dry. Before the first forecast frost, pull up whole plants with their green fruit and hang them upside down in a garage: the tomatoes finish ripening on the plant. A few apples in the crate speed up ripening thanks to the ethylene.