Growing Tomatoes
TheTomato
HISTORYThe tomato is a native of South America, being found in the wild in Ecuador and Peru and was selected over the years into a domestic vegetable. Although we call it a vegetable, strictly speaking it is a fruit. The tomato arrived in Europe in the 1500's but was thought to be poisonous, in fact as we know today, the fruit was edible but the rest of the plant is poisonous. It was called the "love apple¨ because it was considered an aphrodisiac. There is no truth to this claim but tomatoes are rich in minerals and vitamins, particularly A and C, so it is possible that in the past the effect of vitamin C on the eater's general health may have made him feel more virile.
The family name is solanacea in which you will find deadly nightshade and potatoes. As a result of this fact tomatoes are liable to get potato blight if your nearby crop of spuds should succumb to it.
WHERE AND WHEN TO GROW
Tomatoes are one of the easiest vegetables to produce, they can be grown in heated or cold greenhouses, outside in the garden, in pots on the patio, in window boxes if you only have a balcony, in hanging baskets and in grow-bags inside or out. Where you grow the plants will determine how early in the summer you will be picking the fruit. Seed sown in January and kept in heated conditions will give you a first picking in May, sown in February and then into a cold greenhouse you get fruit in June and sown in March and moved outdoors into the vegetable garden in late April fruits will be ready from about late July. The earlier you sow the more expensive your crop will be because of the cost of heating, but the more expensive they would be in the shops if you had to buy them. Whichever growing period you choose, the sowing rules are the same.
The variety you choose will have a bearing on where you can grow them. All varieties can be grown outdoors but there is no point in buying expensive F1 hybrid seeds for outside use when much cheaper standard varieties will do just as well. Growing in heated greenhouses you must use F1 hybrid varieties because the environment of a hot moist greenhouse will be perfect for both your tomatoes and lots of diseases and F1 hybrids have resistance to these diseases bred into them. In a cold greenhouse you can usually get away with using standard varieties but they may get disease in a poor wet summer.
SOWING
Tomatoes need a minimum temperature of 16C (61F) to germinate, although they will tolerate slightly lower night temperatures. Commercial crops begin in January but very often at that time of year the light levels are low so artificial lighting would be required, for growing on as well as germination Ħs not very practical for the home gardener. For the home gardener February is the earliest sowing time but only if you are going to keep the plants inside and heated until summer truly arrives. The best time to start is early March. These plants can be kept indoors until frosts have gone or moved into cold but frost-free greenhouses in April. Sow 2 or 3 seeds 1¨ (2cms) deep in a 9cm pot of good compost. Water the compost before you push in the seeds. Stand the pot in a polythene bag tied at the top and place on a window sill that will get good light but not full sun.
Alternatively you can use small electric propagators or heated benches in a greenhouse. When the first signs of the plants come through the compost start to ventilate the propagator or untie the top of the bag and gradually roll down the sides as the plants grow. When the plants have formed 2 true leaves, (the very first leaves after germination are not true leaves), the plants can be transplanted into individual 9cm pots of compost. To do so, with an old knife carefully lift each plant with a nice clump of compost around the roots and drop this into a hole in the centre of the compost. Gently firm in the plant and give it a little water. This pot should last the plant until it is time to put it into its final position. Keep them in a warm place, if it is a window sill turn them regularly so they get even light, don't over water and give a dilute general feed weekly. When plants are 6 to 8 weeks old they will be ready for planting out. Harden off the plants thoroughly before planting outside and ensure that the ground temperature is 10C (50F) before planting, and that there is no chance of frost.
The soil for outdoor planting should be about 6.0 to 7.0 Ph level and be fertile, well drained but retain moisture, preferably on the sandy side. Dig in manure or a general fertiliser before planting out. Space plants between 18¨ (45cms) to 24¨ (60cms) apart - the closer spacing will give slightly earlier crops. SIZE
The size of crops depends primarily on the variety you sow. Bush varieties need no side shooting (a form of pruning) and no support. As they grow low to the ground it is a good idea to lay black polythene or straw around the plants to keep the fruit off the ground. The fruit of the size found in shops are from standard varieties grown with the support of a can or a string if in a greenhouse. They require side-shooting, which is the removal of the stem that will start to grow where the leaf stem meets the main plant stem. These are best removed in the evening when the sap will run less. A tomato plant will continue to grow as long as it gets warmth, food and water, but at some point it is necessary to stop the growth otherwise the fruit will not ripen; all energies go into fruit production and ripening becomes a second priority.
Outdoor plants should be stopped by pinching out the growth point when the plants have made 4 or 5 trusses of flowers. Indoor plants can be allowed to go to 6 trusses. Bush varieties do not require stopping, they do it themselves. Small, superbly flavoured fruits can be produced by choosing a variety like Gardener's Delight which, requires staking and side-shooting, but forms trusses which have lots of flowers and fruits that are the size of large grapes.
CARING FOR YOUR TOMATOES
Tomatoes are hungry plants and need regular feeds of all purpose fertiliser until the first fruits set and from then onwards they require a high potash feed which is found in the special tomato feeds in your local garden centre. Watering is very important, especially once the fruits are formed. Regular watering, twice a day in the height of summer is vital. Try to keep to the same times each day and also if possible try to use tepid water, leave a full watering can in the greenhouse for this purpose. Irregular water will do two things. Firstly you will get split fruit caused by the skin hardening when short of water and on watering the flesh inside the fruit expands, meaning the only thing that can give way is the skin. Secondly you may get the delightfully named Blossom End Rot, which is rotting of the fruit making them useless.
Whilst tomatoes are easy to grow, given note of the need for warmth, they are not so easy to keep alive and healthy. They are susceptible to all sorts of diseases and aphids love them. Greenfly from out side will often bring with them diseases from potatoes that would not badly damage an outside plant, but in the confines of a greenhouse can prove fatal. Whitefly can ruin a tomato plant, but thankfully whitefly are not keen on the smell of french marigolds and the simplest way to keep whitefly out of a greenhouse is to put a few french marigolds in pots around the place. Tomatoes will curl up and die at the merest hint in the air of a hormone weed killer. It's been known for gardeners to treat their lawns for weeds and a week later walk across their grass and into their greenhouse. Without realising they have trailed in a killer, within hours the leaves have curled and the stems distort as if writhing in agony. Nothing will save the plant then.
CONCLUSION
There is no doubt that given tender loving care, tomatoes are one of the most satisfying vegetables to grow, if only because they taste so much better than the offerings sold in supermarkets under the same name. Back to top