by Sarah Smith•24th February 2012
Ask a passionate gardener which edible crop they would grow if they had space for only one, and you will often get the answer, 'tomatoes'. If you have ever tasted a just-picked, perfectly ripe tomato you'll understand why. It's not just the freshness and flavour, but the warmth of the sun still held in the skin and juice as you bite into the fruit that makes this the desert island plant for many home growers.
So how do you get from a packet of seeds to perfect, tasty tomatoes? Well, it takes four or five months, and one essential ingredient - warmth. Tomatoes are fairly easy-going plants, but they do need warm weather to grow well. Growing them outdoors needs a good summer. You can help them along by providing a sheltered, sunny spot against a south facing wall and, if you have one, a greenhouse or poly-tunnel extends the growing season.
Choosing the right variety is another key thing. The ideal tomato will be suited to your particular growing conditions, and produce masses of delicious tomatoes. There are literally thousands of tomato varieties, offering a range of colours and sizes, different growth habits and degrees of resistance to disease. They can be grouped into three main types: cordon, bush and dwarf.
Cordon tomatoes grow tall and need support, but produce fruit over a longer period than the bush or dwarf varieties. These are good if you don't want a glut of ripe tomatoes all at once. Bush varieties need less maintenance – you won't need to worry about pinching out the side shoots, but the fruit tends to ripen all at the same time. Dwarf varieties have been bred to grow happily in smaller pots or hanging baskets, and make a good choice if you're looking for a plant that doesn't take up a lot of space. And just to complicate matters further, different tomato varieties suit different uses in the kitchen. Plum tomatoes tend to have less juice and make good sauces, large tomatoes taste great sliced for salads and chopped for bruschetta, while cherry tomatoes are easy to pack for picnics and lunchboxes.
Once you have your seeds, the next step is to get sowing - but don't be tempted to start too soon. Tomato plants will grow quickly, so early March is a good time to sow seed for greenhouse plants. Leave it a little later if the plants are going outdoors – early April will be fine. Sow the seeds in a small pot filled with good quality seed compost, leaving about a finger's width between each seed. Lightly cover with a little more compost and put the pot somewhere warm. A heated propagator speeds up germination, it will take a little longer on a warm windowsill. You can help the seeds along by covering the pot with a small polythene bag to trap warmth and moisture. The first signs of growth should appear after about a week - if it's taking much longer try moving the pot to a warmer position.
As soon as they emerge, the seedlings need plenty of light, as well as warmth, to keep them growing strongly. Water them gently, keeping the compost just damp. Once the plants are sturdy enough to handle you can pot them on, very gently, into individual 9cm pots. Planting them nice and deep, with the compost almost up to the level of the first leaves, encourages more roots to grow from the stem. The young plants will be happy in these pots until they have developed their first flowers, in fact the confined space will encourage them to produce those first flowers.
When the weather has warmed up and the first flowers have formed, the plants can move to grow bags or larger pots in their final growing positions. Plants that are moving outside need to be acclimatised to the cooler conditions gradually. Before planting them out, leave them outside in a sheltered position during the day and bring them back inside at night for a couple of weeks.
Regular watering is really important for a good crop of tomatoes. Try to keep the compost moist at all times, watering little and often is best. Allowing the compost to dry out too much between waterings can lead to split fruit and other problems. On the other hand, too much water and you may end up with flavourless tomatoes. With a bit of experience, you'll soon get the balance right. Add some tomato feed to the water once a week from the time the first flowers form to boost your tomato crop and keep the plants healthy.
If you're growing cordon or bush tomatoes, you will need to provide them with some support – a bamboo cane pushed into the pot will do for most varieties. Tie the plants in to their support with a soft twine as they grow. Cordon tomatoes also benefit from having any side shoots that form in the angle where the leaves join the main stem, pinched out. You can also pinch out the growing shoot of cordon varieties when the plant has five or six trusses (bunches) of fruit growing. This encourages them to concentrate their energy on fruit production rather than growing ever taller.
There's a long list of problems that can affect tomato plants, but with a bit of care they are usually trouble free. Blight is a fungal disease that may strike, especially in outdoor-grown plants when the summer is wet. You'll know if your plants have blight – the leaves and fruit will turn black or brown very quickly. Dosing plants with Bordeaux mixture is said to help guard against blight. Whitefly and aphids can become a problem too, but growing the right plants close by can help to deter them. French marigolds are the traditional, and attractive, way to keep whitefly at bay, and basil lures aphids away from your tomato plants.
So, after all that care and attention, in a good summer, you should have tomatoes ready for harvest by late July. Pick them when they are a bright, even colour, (depending on which variety you are growing this may be red, yellow, orange or deep purple), and the fruit comes away from the plant easily. Then all you need to do is decide how to eat them. Straight from the plant, still warm from the sun? Mixed with a good glug of olive oil, some salt, and a sprinkling of basil? Blended with onion and garlic for a cool gazpacho? Or slow roasted with oil and herbs? When faced with a harvest of ripe tomatoes there are so many choices - best to grow plenty then.
Sarah Smith’s kitchen garden blog can be found at www.thegardendeli.cordpress.com