The main things to master about growing tomatoes outdoors, are choosing and sowing the seeds (or buying young plants); planting on in pots to grow into young plants ready for planting out; feeding and watering; pruning and thinning; harvesting: Job done!
The rewards for getting it right (with our help) are good crops of juicy and flesh tomatoes that will keep you going through until and beyond, the first of the autumn frosts!
Leaving aside the tomatoes that can be grown in hanging baskets – of which more later – there are two basic types of tomato plants for growing outdoors. Cordon tomatoes are normally grown up a cane or other support, and the bush tomatoes, which will also need a bit of support, but literally grow into a multi-branched bush.
You also have to decide whether to grow in a container, grow bag or big pot, or in a suitable place in the garden. A wide range of choices awaits you. Give a little time and thought and you are well on the way.
As a rough guide, from sowing to having a plant ready for planting outside takes about 6 weeks. Working backwards from a good planting out time - first week in June earliest - a good time to sow your tomato seeds in the house or in a heated propagator would be in middle of April. This sowing date should allow you to sow and grow on the tomato seedlings without any check to their growth, so you be planting outdoors a tomato plant which is full of life and ready to go.
For sowing tomato seeds, use a good compost rather than garden soil; sow thinly in pots or small seed trays, or better still, sow the seeds in seedling unit trays - two seeds to a segment. Germination will be quicker if at a temperature of around 65 deg. After the seeds have germinated, they can be moved to a slightly cooler place with a temperature of 60deg.
Once your seedlings have 2 pairs of real leaves, then they can be carefully potted into individual small pots of about 3.5in diameter. You should be able to do this around 3 or 4 weeks after initial sowing. So prepare for the fact that you are going to need space in a light position somewhere in the house where a temperature of 60deg can be maintained.
If you cannot meet the conditions raising young plants indoors, then the best way forward is to buy young tomato plants at your local garden centre. Pre-order if you can, because young tomato plants are popular and well sought after.
Do not make the basic mistake of planting your tomato plants outside in the garden too early, or before they have been properly hardened off. This is probably the number one cause of failure. Tomatoes are not hardy plants. They need warmth. If there is any suspicion of frosts, then keep the tomatoes indoors.
Outdoor tomatoes can be planted direct into a garden bed, or they can be grown in a wide range of containers. If there is no space in your garden - and your tomato plants need only a 12in square area - then opt for a grow bag, or a large plastic pot. If a pot is used, then a diameter of around 15in would be best, and use a saucer under to help conserve moisture and even as a secondary source of watering. Tomatoes need water and plenty of it.
A soil plot near a sunny fence or wall would be good as this will help when supporting your cordon tomato. It will also allow the tomatoes a good root run to find food and moisture. However, many commercial tomayo growers grow their tomatoes in containers - often in growbags - as this gives them more control over watering and feeding as well as prevention of disease build up in regularly planted soil situations.
Growing in a crop bag or large pot is a suitable option for the amateur grower. It has the advantages of you being able to grow the tomatoes in a position of your own choosing on patio or any spare plot of land. You will also be better placed to control the watering and feeding.
Growbags are best situated near a wall or fence to make it easier to support the tomato cordons. If you are growing bush type tomatoes, then this need not be a concern, as with tomatoes grown in a large pot which is deep enough to support a cane. The cane will need to be at least 4ft above soil level. Alternatively if grown near a fence or wall, the tomatoes can be supported with soft string - loosly tied to the base of the plant and then to a point 5 or 6 feet up a wall or fence. The tomato plant is then supported by gentle twisting the sting around the main stem as the plant grows.
Once you have your tomatoes planted, they will grow quite quickly, so will need constant attention to watering, feeding, supporting, and side shoot removal. Then comes the really easy part of picking and eating!
Watering and feeding as necessary are vital for good crops - especially if grown in any form of container. A good start it to try and get the pot or growing bag sheltered from the afternoon sun in particular, though not the actual plant, which will need goon sun.
Watering in a grow bag is relatively easy to do because the shallow depth of soil allows the water to get down to the roots where it is needed. Those grown in large deep pots will need a good drench watering to ensure this. That is why i suggested the saucer under the pot. On no account should the plants be allowed to dry out because of lack of water. But neither should they be allowed to remain flooded in grow bags in particular. Punch a few drainage holes in the base.
A feed with liquid tomato food weekly will keep the plants growing well. You will be spoilt for choice with liquid feed. Go for one of the brand names to ensure good quality if you must, but a quick look at the NPK stats on the bottle will show you that they are all very similar. Do not over feed or you will end up with a canopy of lush foliage and few fruit. Just do what it says on the bottle.