Ask a gardener which edible crop they would grow if they had space for only one, and you will often get the answer ‘tomatoes’. If you’ve 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.
Tomatoes are fairly easy-going plants, but one thing they do need to grow well is warmth. Originally from South America, they are just about at their climatic limits in the UK. Growing them outdoors relies on some good summer weather, but in a sheltered, sunny spot, cherry tomatoes or some of the early maturing varieties should do just fine. A greenhouse or polytunnel extends the growing season, and gives some protection from blight which can strike in warm summers.
There are literally thousands of tomato varieties, offering a range of colours and sizes, different growth habits and degrees of resistance to disease. All these varieties can be grouped into three main types cordon, bush or dwarf. Cordon tomatoes grow tall and need support but produce fruit over a longer period than the bush or dwarf varieties. Bush varieties don’t need as much support as cordons, and you won’t need to worry about pinching out the side shoots, but the fruit tends to ripen pretty much all at the same time. Dwarf varieties have been bred to grow happily in smaller pots or hanging baskets and are a good choice if you want plants that look good and don’t take up a lot of space. The different varieties suit different uses in the kitchen too. Plum tomatoes have less juice and are good for making sauces, large tomatoes taste great sliced in salads and chopped for bruschetta, while cherry tomatoes are easy to pack for picnics and lunchboxes.
Growing tomatoes from seed gives you the widest choice of varieties. The seeds germinate easily, but don’t be tempted to sow too soon. March is a good time to start seed for plants that will be growing in a greenhouse or polytunnel. Leave it a little later if the plants are going outdoors – early April will be fine. Sow the seed in a small pot filled with a good quality seed compost. Level the compost and firm it down gently, before watering lightly, then sow the tomato seeds about finger width apart. Lightly cover them with a little more compost and put the pot somewhere warm. A heated propagator will speed up germination, but a windowsill is usually fine – covering the pot with a small polythene bag helps keep the compost moist and warm. You should see signs of growth in about a week, if it is taking longer try moving the pot to a warmer position. Once the first leaves have pushed up through the compost, the seedlings will need plenty of light to prevent them growing tall and thin. As they grow, keep the compost moist, but not soggy – too wet and the small plants may rot. Watering into the saucer or tray the pot is standing on, rather than directly onto the compost, can help to prevent this. Once the plants are sturdy enough to handle they can be potted on, very gently, into individual 9cm pots. Plant them nice and deep, the compost should come almost up to the level of the first leaves, this will encourage more roots to form from the stem. Water gently and put the pots in a sunny position. The young plants will be fine in these small pots until they have developed the first flowers.
When the flowers start to form, it’s time to move the plants to a larger pot. By now the weather should have warmed up enough for the plants to move to their final growing position. Plants that are going outside need to become used to cooler conditions gradually; put them out into a sheltered position during the day and bring them back inside at night for a couple of weeks. You should also start feeding your plants at this stage. There are lots of tomato feeds available, both organic and non-organic, they are easy to use and can make a big difference to your tomato crop.
Regular watering is key to successful tomato growing. The best time to water them is in the morning when the plants have a growth surge and can use the extra moisture. Try to keep the compost moist at all times, watering little and often is best. In hot weather the plants may need watering twice a day. Allowing the compost to dry out too much between waterings can lead to split fruit and other problems. On the other hand, give too much water and you may end up with flavourless tomatoes. With a bit of experience, you’ll soon get the balance right.
As your plants grow taller, they will need some support (unless you are growing a dwarf variety) – a sturdy cane pushed into the pot will do for most varieties. Keep tying the plant to the support with a soft twine as it grows. If you are growing cordon tomatoes, carefully pinch out any side shoots that form in the angle where the leaves join the main stem. You can also pinch out the growing shoot of cordon varieties so that they concentrate their efforts on fruit production rather than growing ever taller. To do this, wait until the plant has five or six trusses (bunches) of fruit growing, then count two leaves above the topmost truss and pinch the main stem cleanly off.
Blight can be a problem with tomato plants, especially in a wet summer. It’s fungal disease, more commonly seen in outdoor-grown tomatoes. It strikes quickly too. You’ll know if your plants have blight – the fruit turns black and shrivels on the plant, leaves curl up, becoming black or brown. Dosing plants with Bordeaux mixture on a fortnightly basis is said to help guard against blight. Whitefly and aphids love tomato plants and can be a nuisance. Planting French marigolds close to tomatoes is the traditional organic, and attractive, way to help deter whitefly. Greenfly prefer basil to tomatoes. Grow this herb close by to lure aphids away. If the basil plants become badly infested, they can easily be disposed of – along with the aphids.
In a good summer, you should have tomatoes ready for harvest by late July. Ripe tomatoes have an even colour, depending on which variety you are growing this may be red, yellow, orange or deep purple, and should come away from the plant easily when picked. Now the biggest challenge is getting your home-grown tomatoes to the kitchen without being tempted to eat them first!