If you are intending to grow your tomatoes outside, you will need to "harden off" the plants before planting them outside. This means getting the plants used to the cooler, less clement conditions outside, as opposed to controlled conditions in a greenhouse, lean to or indoors where the seedlings have previously grown. If you intend to grow tomatoes outside, in late spring you will need to place the plants outside, starting on days when the weather is at its best, placing the plants outside for increasingly longer periods. Only leave outside overnight once the risk of frost has passed.
Upright tomato plants get quite large, around 1.5 m (5 ft+ ) so they need plenty of support, especially later in the season when the branches are heavy with fruit and can easily snap. All upright tomatoes need to be tied to canes to support the plant and the fruit. The image illustrates the wrong way to tie in a tomato plant. When the tie was put on, it probably looked Ok but as the plant has grown, the tie has tightened and damaged the stem. To avoid this use soft ties, check regularly and loosen as the plant grows. I like raffia as a plant tie, it's very strong and looks natural.
Temperature wise tomatoes are less than happy below 15 C at night, and below 10 C could damage the plant. If the weather turns unexpectedly cold, protect the plant with a fleece. Equally too hot and the plants are not happy, ideally not above 35 C. This means on very warm days it is essential to ventilate the greenhouse and perhaps spray the floor with water if it is very hot to cool the greenhouse. It follows from this that almost all conservatories in the summer months are too hot for growing tomatoes.
Tomatoes are vigorous plants and once they get going, and the light levels are good, tomatoes grow quickly. For a good crop it is important to direct the plants's energy into fruits not flowers.
Next step in tomato growing, which is very important
Removing side shoots.