Growing Tomato Plants | Grow Tomato | Garden Tomatoes

The tomato originated in the Andes, South America where tomatoes grow wild. It is believed that they were first cultivated by the Aztecs and Incas, possibly as early as 700 AD. The tomato plant arrived in Europe in the 16th century, supposedly brought back from Central America by the Spanish Conquistadors, although another legend suggests that two Jesuit priests took them to Italy from Mexico.

At that time tomatoes were also known as wolf's peach and Peruvian apple. In the UK, the Elizabethans thought the bright red color of tomatoes was a danger signal and regarded them as dangerous fruits. In fact, it is true that tomatoes are related to the nightshade family.

That's enough of the history, fresh from the garden, the tomato is delicious wherever it originated from!

Tomatoes are sub-tropical plants and therefore require a full sun position when grown in temperate zones. A position against a wall or fence will give an even better chance of success as long as they can receive sufficient water.

Tomato plants grow very well in raised beds, they appreciate the soil conditions which provide moisture without water-logging.

Soil Preparation

Two or three weeks before planting, dig the soil over and incorporate as much organic matter, such as compost or well rotted manure, as possible. The aim is to make the soil able to retain the moisture needed so much by tomatoes.

When To Sow Tomato Plants

Tomatoes are unable to tolerate any degree of frost, the timing for planting or sowing outside is therefore key to successfully growing tomatoes. If the tomato seeds are to be sown directly outside (not really suitable in cooler climates), they must be sown when the soil temperature is (and will remain) above 10C (50F) - any lower and the seeds will not germinate. In practical terms this normally means 3 weeks after the last frost date in your area.

Where the seeds are sown under cover (poly tunnels or cloches) or indoors, aim to sow the seeds so that they reach the stage where they can be transplanted outside, three weeks after the last frost date.

Tomato plants plants take roughly 7 weeks from sowing to reach the transplanting stage and they should be transplanted outside one or two weeks after your last frost date. Therefore you should sow them 7 weeks before you plan to transplant them outside.

The following sowing / transplanting methods are available to the amateur gardener who wants to grow tomatoes outside without the use of a greenhouse.

Sowing Tomato Seeds Directly in a Seed Bed

This is by far the riskiest method in temperate climates. It is only suitable for those areas which have a last frost date in MARCH. In all other areas, the soil is unlikely to be warm enough at a time which will allow the tomato plant to develop and fruit. The soil temperature must be at least 15C (60F) at the time of sowing and during germination. Use a cloche or cold frame, this will warm the soil prior to planting and protect the plants in their early stages.

Soil preparation needs to be done as described above. Using a trowel, dig a shallow drill 2.5cm deep (1in) deep in the prepared bed. Place two seeds every nine inches in the drill and cover the seeds to a depth of 2.5cm (1in). Water well if the conditions are at all dry.

The seedlings should emerge in about 10 days. When they are 5cm (2in) tall, thin to one plant every 45 to 60cm (18 to 24in). The plants can then be cultivated as described in the main article.

Sowing Tomato Seeds Indoors

This is one of the commonest methods and produces good results. Sow each seed (two if you have a surplus) in a 7.5cm (3in) pot, lightly covering them with potting compost. Ensure the compost is moist but not waterlogged. Place them in a warm (up to 27C or 80F) draught free place - the seedlings should emerge in 7 to 10 days time.

Immediately this happens, move the plants to a light position (a light windowsill is ideal), but out of direct sunlight to avoid burning the leaves. Where more than one seed has been sown per pot, thin out the least healthy seedling as soon as they are large enough to handle.

When the roots start to come through the base of the pot (about 4 weeks after sowing), transfer the plants to larger 12.5cm (5in) pots.

The plants will be large enough to transplant outside about 7 weeks after sowing the seed.

Sowing Tomato Seeds Outdoors In Pots

This method is similar to sowing the seed indoors in pots with the exception that the pots are stored outside whilst the seed germinates. The advantage over indoor sowing, is that space is not a limiting factor to the amount of plants to be raised.

Timing and position of the plants are the key factors to success. Keep the pots in the warmest part of the garden (against a house wall is ideal) to hasten germination and subsequent growth. The use of cloches will assist greatly in retaining heat.
Timing is the most difficult aspect of this method - keeping the plants under cloches and or against a house wall will raise the temperature and permit earlier growing, but it is not an exact science. The basic rules of no frost and a minimum soil temperature of 15C (60F) must be achieved.

One combination which can work well is to sow the seeds inside (where they do not have to be in a light position) and the transfer them outside when the seedlings emerge.

Tomato Support

Just before transplanting the tomato plants to their final position drive a strong stake into the ground 5cm (2in) from the planting position. The stake should be at least 30cm (1ft) deep in the ground and 1.2m (4ft) above ground level - the further into the ground the better the support.

Tomato Transplanting

Where tomato seedlings have been started in pots, they should be transplanted into their final positions when they are about 15cm (6in) high. Two to three weeks prior to this, the plants should be hardened off.

For each plant, dig a hole (45cm / 18in apart) in the bed to the same depth as the pot and water if conditions are at all dry. Ease the plant out of the pot, keeping the root ball undisturbed as far as possible. Place it in the hole and fill around the plant with soil. The soil should be a little higher than it was in the pot.

Loosely tie the plant's stem to the support stake using soft garden twine - allow some slack for future growth.

Container or Grow Bag Culture

The culture of container grown tomatoes is not very different from other methods. The soil used for containers is best half potting compost and half a soil-based type loam - this gives some weight to the soil which helps the stakes to remain in place and stop winds blowing over the container.

The plants will need more frequent watering to keep the soil moist, and will require feeding with a liquid tomato fertilizer once a week starting when the first fruits start to form.

Weeding, feeding, watering and support are the main needs of tomato plants.

Watering

A constant supply of moisture is essential for tomatoes - dry periods significantly increase the risk of the fruit splitting. Tomatoes don't like being water-logged, but neither can they stand dry conditions.

Feeding and Weeding

Growing outside, the plants should be fed with a liquid tomato fertilizer every two or three weeks up to the end of August. These tomato fertilizers are high in potash which the plants needs to fruit well. In September, feed with a general fertilizer (higher in nitrogen) in order to help the plant support it's foliage. Weed around the plants to discourage pests and diseases. A mulch of well-rotted compost will help retain moisture and prevent weeds.

Support

As the plant grows, tie in the main stem to the support stake - check previous ties to ensure that they do not cut into the stem as the plant grows.

Pruning to Shape

As far as pruning is concerned, tomatoes come in two forms, bush (or determinate) and upright (indeterminate or cordon).

Bush varieties do well for cultivation outdoors because they require no pruning for most of the season. Remove any yellow or decaying foliage as soon as possible to avoid the spread of disease.

If your bush tomatoes become too large to support themselves, either trim out a few major branches or add more support canes - the side branches can then be tied into the additional support canes.

Limit the number of trusses of tomatoes to seven or eight by pinching out any surplus ones.

Upright varieties are commonly cultivated in pots, grow-bags, the greenhouse and sometimes outdoors in open soil. When the first fruits begin to form, the plant will produce side-shoots in between the main stem and the leaf stems.

These side shoots should be removed by pinching them out with the fingers. If allowed to grow they will produce a mass of foliage but few tomatoes. Any shoots which have been overlooked and allowed to grow should also be removed. Lower leaves which show any signs of yellowing should also be removed to avoid the risk of infection.

When the plant has developed six or seven trusses of tomatoes (normally around July time), 'stop' the plant by breaking off the growing tip. If any more than seven trusses of tomatoes begins to develop, pinch them out to encourage the plant to produce good quality tomatoes rather than an abundance of low quality late-maturing fruit.

Harvesting Tomatoes

Pick as soon as the fruits are ripe (color and size will identify this) for the best flavor - eat as soon as possible. This also encourages the production of more fruit. As soon as a frost threatens, harvest all the fruit immediately and ripen them on a window sill. With upright varieties, it is possible to gently flatten the plants onto the soil and cover with horticultural fleece to protect them from the frost.

Whitefly

Whitefly are the most likely pest to affect your tomatoes. The adult flies (they look like tiny moths) lay eggs on the underside of leaves. The growing eggs feed on the leaves, leaving a sticky secretion which attracts other diseases.

As soon as you see the eggs, try spraying with water to wash them off and remove others by hand. If the attack looks like getting out of hand, there is no alternative to spraying - your garden center will have several types of spray available.

Red Spider Mite

These are normally only a problem in dry times. The mites are not visible (they are too small), but the leaves become mottled and yellowing. The solution is is to spray the plants with a fine mist of water as often as possible - red spider mites hate moist conditions.

Aphids (Blackfly and Greenfly)

Planting Marigolds really does attract beneficial insects such as ladybirds and hoverflies and these love to eat blackfly. Spraying the plants with water also works - it simply knocks the blackfly off the plant. Where neither of these methods work, it's down to the garden center for a chemical spray - most work well.

Foot and Root Rot

Foot and Root Rot in tomatoes is often caused by irregular watering, the base and roots of the tomato plant begin to rot causing the leaves to discolor and the tomato plant may eventually collapse.

Mosaic Virus

There are many varieties of mosaic virus which can affect tomatoes but they can all be identified by leaves which turn yellow, then bronze and become distorted. This is a very infectious virus which can be transmitted by humans from plant to plant.