Robin Gale-Baker, from Sustainable Macleod discusses how to grow tomatoes. This is one of a series of articles she has written about growing various veggies (see right hand sidebar). She has also written a number of articles about growing various herbs, growing various fruit trees and general growing techniques.
Also, read Helen Simpson’s guide to growing tomatoes.
Top hints for growing tomatoes
- Plant tomatoes deeply – at least half way up their stems (you can leave the lower leaves on or twist them off). Deep planting anchors the plant; the buried stem will put out roots, taking up more water and nutrients and producing more fruit.
- Always keep tomato roots moist otherwise the plant will begin to die.
- Stake your plants or use a tomato cone to prevent wind damage and breakage.
- Choose heritage tomatoes and save seeds from the fruit for planting the following season.
Positioning tomato plants
Full sun. Choose the third hottest part of the garden for tomatoes, reserving the hottest for eggplants and capsicums.
Dig over soil with a fork, loosening it and breaking up clods to a spade’s depth. For a 2 x 1 metre bed dig in a barrow load of compost, a bag of cow manure and 2 handfuls of blood and bone. 4 – 5 handfuls of gypsum will also add calcium and break down clay. Add some potash, and sprinkle this around each plant. Add potash again at the time of flowering.
Planting and spacing tomatoes
Sow seeds in punnets and plant out as seedlings. Start raising seeds in June and plant out in September. Protect seedlings if frost is expected. To get a head start, plant seedlings into large pots with lots of compost, and plant well established plants out when you are certain frosts have passed. Plant out seedlings 1 metre apart in rows 1 metre apart. As the plant grows, remove lower leaves. Once the lower 30cm of the stem is free of leaves, the likelihood of spores jumping from the ground onto the leaves and moving upward, infecting the plant with septoria, is much reduced.
Planting tomatoes in pots
Tomatoes can grow well in pots. Use a good quality potting mix and add plenty of compost and well rotted animal manure or pelletised manure. Plant one tomato per pot in a pot at least 40cm in diameter. Stake the plant and keep soil moist at all times.
Laterals are shoots that grow between the stem and a main branch. Most people remove them but a Diggers’ experiment found that it made no difference to the quality or quantity of fruit. If you do pinch them out, insert them into some potting mix, water well and within 7 -10 days they will have roots and you will have extra plants.
Water directly onto soil or mulch, and if mulch, make sure the soil below is moist. Water with a soft stream from the hose or watering can or with dripline. Remember to water to the roots and not the leaves, and to NOT splash soil onto lower leaves. Water seedlings at the time of planting and every second day for the first couple of weeks; thereafter water deeply twice a week. Tomatoes must never dry out and need a lot of water in summer and as fruit develops.
How to avoid blossom end rot
Blossom end rot is a condition that as the name implies, causes rotting on the underside of tomatoes. Technically, it is a result of the plant getting an inadequate supply of calcium but this is usually caused by the plant not getting sufficient water to its flowers and fruit. Strengthen the water delivery system by applying additional potash (available in packets from your nursery) around each plant at the time of flowering, and make sure you are giving the plant adequate water.
How to avoid sunburn
When there is an extreme heat event, tomatoes can burn and blister. Blisters manifest as white, soft skin blemishes. Rig up a quick shade house by banging four star pickets into the corners of the bed, drape with shade cloth or old sheets and secure with yellow star picket caps. Alternatively just drape an old sheet over the plants. Water deeply BEFORE the heat event. A well hydrated plant will not burn or wilt.
Do not grow in the same place, or where other members of the Solanaceae family such as eggplants, capsicums and potatoes have been grown, for three years.