Growing Tomatoes

Can you imagine life without tomatoes? It’s hard – they’re such a basic ingredient of so many of our favourite Western and Indian dishes. Yet it’s odd to think that not even two centuries ago they were regarded with great suspicion in Europe. The Spanish imported this exotic ‘vegetable’ (it’s technically a fruit) into Europe from Mexico in the sixteenth century, but its resemblance to the deadly nightshade made people suspicious. It looked lethal! To make matters worse, it also reminded folk of the mandrake herb, known for its lewd, aphrodisiacal effects. Hence its early common name, the ‘love apple’!

Today we know better, and our passion for the tomato is huge. Its acid-sweet, bursting flavour brings so many dishes to life, and it’s good for us too, being packed with the antioxidant lycopene, as well as minerals and vitamins (especially Vitamin C). And because tomatoes combine so well with chillies, it’s not surprising that some of the best ways of eating them are Mexican, salsa being a prime example.

Tomatoes are relatively easy to grow, but they need warm, summer conditions (unless you garden on the subtropical coast, where the growing season is much longer).

Two types to grow

Indeterminate tomatoes are vine tomatoes, with a vigorous, rambling growth that needs to be supported on a trellis. Common varieties of these are various cherry tomatoes and the popular ‘Moneymaker’. Prune or trim the plants to keep their size manageable. They are the ‘racehorses’ of the tomato world, producing high yields, but they are susceptible to disease.

Determinate tomatoes are bush tomatoes that don’t need staking but will certainly benefit from it, especially to keep the fruit off the ground. Common varieties are ‘Roma’, ‘Heinz 1370’ and ‘Floradade’. They are more disease resistant and take up less space. But they have a limited harvesting period, so succession planting – every 3 to 4 weeks – ensures a continuous supply during summer.

How to grow

Prepare the soil with plenty of compost and kraal manure, and make sure it drains well. Plant seedlings in the soil at the same level as the top of the plug.

The seedlings develop rapidly, so the important job of staking should be done sooner rather than later. Stakes offer support, particularly during fruiting, and improve crop yield and quality. Use sturdy wooden, bamboo or metal poles which are at least 1.5 metres tall. Place the stakes 15cm from each tomato plant’s base to avoid disturbing the roots. Once the plants begin to spread, secure them to the stakes using soft cord or twine. Leave some slack, so you don’t impede growth or damage the stems.

Keeping tomatoes healthy

Because this is a fruiting ‘vegetable’, you would do well to supply it with potassium-rich fertiliser while the tomatoes are forming. For the best taste, let the fruit ripen completely on the bush. Tomatoes flourish in conditions with low nitrogen, high phosphorous and moderate potassium, incorporate a complete fertiliser. The plants like an almost neutral (6.5 to 7.0) pH level, so regulate high acidity levels with a sprinkling of agricultural lime in late autumn.

Water deeply twice a week in hot weather but avoid wetting the leaves, as tomatoes are prone to fungal infections. Prevent fungal diseases by removing the bottom 40 cm of leaves. Mulching with straw, grass clippings or compost retains moisture in the soil and discourages weeds.

Regular watering also keeps blossom rot at bay, by ensuring an uninterrupted flow of calcium to the plant. Dry spells in between watering decreased the calcium uptake and this is what contributes to the development of blossom end rot.

Deter white fly by dusting the leaves with yellow sulphur powder, which is available from hardware stores. Put the sulphur in a tin, make holes in the bottom (like a salt and pepper shaker) and shake it over the plant once a week.

Germinating seeds and planting out

Ideally, one should germinate tomatoes in seedling mix and allow them to grow on in the mix for 3 to 5 weeks. Keep the seedlings in a warm, sheltered spot and keep the mix moist. Wait until the weather warms and soil temperature rises before you plant them out – they should be 15 to 20 centimetres tall with the roots developing well by this point. They will require well-prepared soil that drains freely, several hours of sunlight each day and protection from wind. Plant them with the lower leaves just above ground level. As a rule, 75cm spacing should be sufficient, or refer to the seed packet – it will have details of that particular variety’s growth habits. If you are planting several rows leave 1.5m-wide paths between the rows.

Harvesting

It takes about six to eight weeks for a fertilised flower to develop into a mature fruit.

Depending on the cultivar, the ripe tomato could be yellow, orange or any one of many shades of red. The flavour and nutrient content of tomatoes are best if the fruit is allowed to ripen on the plant. If necessary, they can be picked whilst still green and wrapped in newspaper and stored in a cupboard; they will ripen slowly, giving one fresh tomatoes for weeks. Green tomatoes can also be eaten.