Grow Your Own Tomatoes

Growing your own tomatoes can be a very satisfying pastime. Producing tomatoes can encompass all levels of experience. There are many experienced gardeners who will grow tomatoes in a heated or unheated greenhouse, choosing different varieties and planting them from seed. Some gardeners may grow three or four plants inside or outside, having bought their plants from the Garden Centre. In some cases where space is at a premium one plant in a pot or a hanging basket might be all that can be fitted in. What is certain is that a home-grown tomato picked straight from the plant is indeed far superior to a supermarket bought one. The smell and the taste are just second to none!



For those without a greenhouse, growing tomatoes outside may be their only choice and many do this very successfully. A tomato growbag growhouse is an excellent and cheap alternative to a greenhouse. A long hot summer may well produce a good harvest. However one of the disadvantages is that tomatoes grown outside are far more susceptible to blight. Having said that there are many varieties suitable to growing outdoors that have shown some resistance to blight. If grown outdoors thenplace them near a sunny brick wall.



Many gardeners will start off their tomato seed as early as late January/early February to ensure the longest possible growing season. However sowing from March onwards will still guarantee a good crop.


Tomatoes need a temperature of 15 0C to germinate, but will do so quicker if a temperature of 20 0C can be maintained. Sow seed in small pots, filled with seed or multi-purpose compost. Water the compost and then sow the seeds about 2cm (1”) apart, then cover with compost or Vermiculite. Label up the different varieties if growing more than one.


Put your pots into a heated propagator or secure with a polythene bag around the pot with an elastic band and place on a warm indoor windowsill. Any unused seed can be stored and used for next year. Tomato seeds generally have an excellent germination rate.



Tomato seeds take between one to two weeks to germinate. Wait until all the seedlings have appeared and then very carefully tease out the seedlings holding them only by their leaves and plant on into a 7cm (3”) pot filled with multi-purpose compost. You may wish to use a bio-degradable pot at this stage which you can then pot on into a bigger pot later without disturbing its roots. Water the seedlings into their new pots and keep in a dry warm place.


It may take another couple of weeks for the seedlings roots to fill this pot and then it will be ready to pot on into a 12-15cm (5-6”) pot. At this stage it is advisable to use a mixture of John Innes No 2 and multi-purpose compost.



Young plants should be kept at a minimum temperature of 16 0C to ensure sturdy growth. Extra warmth gives stronger growth and ultimately more fruit. Once potted on keep on the dry side for a week or so as this encourages initially the roots to travel deeper for moisture. Establishing a strong root system will pay dividends later in the growing season when the watering demands of the thirsty plants is increased.



Many greenhouse gardeners grow their tomatoes in borders within the greenhouse. There are advantages to this in that tomatoes are thirsty plants and it means roots can go down deeply in search of water. However if tomatoes are grown in the same soil year after year, you run the risk of exposing the tomatoes to disease. Good housekeeping is essential.


Many will choose to grow their tomatoes in pots in the greenhouse or on a patio. Tomatoes can dry out very quickly in a pot, so careful attention must be paid to watering and later on to feeding.


Growbags offer a convenient way to growing tomatoes. They are tailored to three plants per growbag, alternatively you can cut the bag in half turning each half on its end to provide greater depth for rooting and grow one plant in each half.


Another option is to place the pot on the growbag, cut around it and press the pot into position. This allows the roots to spread into the growbag via the pots drainage holes. Tumbling varieties of tomatoes grow very successfully in hanging baskets, provided they are well watered and not allowed to dry out.



There are two types of tomatoes, cordon or bush. Cordon tomatoes continue to grow in height and many can reach as high as 6m (20ft) if allowed to. These are described as indeterminate. Their fruit continues to ripen over a long period and they need supporting right from the beginning.


This type of tomato has to be trained by staking it to a bamboo cane for support. Tie in to the cane as it continues to grow. All side-shoots growing between the stem and a leaf are removed. These side-shoots can be easily snapped off between your finger and thumb. Any shoots growing up from the base of the plant should also be removed.


As the fruits mature the lower leaves should be removed to allow light to the fruit and to aid ripening. In addition if the tomato has reached the top of your greenhouse roof then pinch out the top of the plant. Any side shoots that then appear should be removed as well.



Otherwise known as “determinate” tomatoes, reach their predetermined size and then stop growing. These do not have their side-shoots removed. Equally they tend not to be staked. The time between fruiting and ripening is much shorter than it is with cordons. Tumbling tomatoes are an example of a bush tomato and are grown in hanging baskets.




Tomatoes need heat, water and plenty of nutrition. If you do not have a greenhouse there is little you can do protect them from the cold other than to wrap them in some fleece. However maintaining their water supply is so important.


Tomatoes are hungry plants so digging in well-rotted manure into greenhouse borders or adding a slow release fertiliser to your pots will certainly help maintain good health. When the flowers appear start using a high potash fertiliser, such as Chempak, Tomorite or other tomato feed. This will ensure that the flowers keep coming and help the fruit to ripen. Alternatively seaweed or a homemade solution of comfrey can be used.






Blight manifests itself as pale brown blotches that quickly work their way through the foliage. The fungus can affect the fruit making it inedible. At the first signs of blight spray plants with a Bordeaux mixture (a combination of copper sulphate and lime.)




This appears as a hard brown disc at the bottom of the fruit. It is caused by inadequate watering. The solution is to water more frequently.



The splitting of the fruit is caused by erratic watering or big variations in temperature, which can occur in July. Consistent watering helps.



The leaves curl up lengthways and look as if they are about to die. This is caused by big differences between day and night temperatures. The solution is to try and balance the temperature, a difficult one.



The adult whitefly lays its eggs on the lower leaves of tomato plants. The adults feed on the leaves, damaging plants and restricting the crop. Many gardeners swear by companion planting such as French Marigolds or Basil.



There are a number of viruses that affect tomatoes, manifesting themselves in yellowing, mottled, wilting leaves. Once a virus has set in there is very little that can be done. Prevention is helped by good hygiene and healthy soil.




Keep picking tomatoes as they continue to mature and ripen. Keep up the watering, feeding and pruning and they can continue to reward you, weather permitting well into autumn.