Tips on growing – Tomatoes

The Tomato seeds we offer for sale are mainly cordon types of tomatoes – that is, they grow tall up strings or canes. Tumbling types of tomatoes do not need any supports, and do not need to have side shoots taken out. They are usually grown in an unheated greenhouse, but can be grown outdoors in mild, sheltered locations (see notes at the end). Some cordon types will do well outside too especially the cherry types. Tomatoes will not tolerate frost at either end of the season.

Sow seeds in a propagator at 18C degrees mid March to the beginning of April. Sow the seed 1/4 cm deep thinly spaced out in a seedtray, or sow one seed in each plug of a plugtray. Use good quality seed compost. Germination can take 7 to 10 days. Check at least once a day and keep moist but not overwatered.

Pricking out
When the second pair of leaves have appeared, ease up each plant without any damage to the roots using a plastic plant label or similar. If sown in plugtrays, push up the whole plug without disturbing the rootball. Plant each seedling in a 7cm pot using good quality potting compost. Water little and often. Grow on at 18C degrees. Give plants enough space so that they do not shade each other as they grow. They need good top light. the final watering in this size of pot should be with an organic liquid feed.

Potting on
When the plants are 15cm to 23cm tall, with the first flowers forming and at the beginning of June, pot on the plants to their final large pots. These should have a minimum diameter of 23cm. (If plants are to be grown outside – harden them off over a few days before planting out.) Plant into the large pots so that the lowest leaves are just above soil level. More roots will then form up the buried stem. Leave 7cm at the top of the pot for watering. Place pots 45cm from each other to allow ventilation between plants. Grow Tagetes (bedding French Marigolds) in pots between tomato plants and dotted around the greenhouse to deter whitefly.

Support the plants (the tall or cordon tomato types only) by attaching string to the stem below the first true leaves. Attach the other end of the string to overhead wires. Each plant can then be twisted gently round its string as it grows. Alternatively, support the plants by tying loosely with string to bamboo canes.

Maintaining and growing on
Up the main stem, between each leaf and the stem, side shoots start to develop. these must be removed when quite small using a knife. These do not need to be removed if growing tumbling tomato types. 

Spray plants gently in the early morning with a fine mist to help disperse pollen which sets the fruit. Also tap on the bamboo canes or string to help with this.
Keep the greenhouse well ventilated.
Give the plants an organic seaweed-based fertiliser formulated for tomatoes once a week until they start to flower and fruit. then change to a high potash organic tomato feed, such as liquid comfrey, to encourage flowering and subsequent fruiting.

When the plants reach 1.5m tall (cordon types), cut off the lower leaves up to the first truss of tomatoes. This will let more air around the fruit. Remove these leaves from the greenhouse. Cut off the tip of the tomato plant when it reaches the roof. Let 4 or 5 trusses of tomatoes grow on.

Growing outdoors
To grow well outdoors, tomatoes need a sunny site, sheltered from the wind. Against a south-facing wall is perfect. The soil must be well drained. Do not grow near potatoes.
Prepare the ground the previous winter by digging in well-rotted organic compost. Before planting in early June, fork in a general balanced organic fertiliser, and wilted comfrey leaves if available. Tomatoes can be grown through holes in black polythene to conserve moisture and prevent weeds. Alternatively a mulch of straw can be put round each plant. If possible place cloches over the young plants for a few weeks.
Continue to grow on as for greenhouse tomatoes.

Outdoor tomatoes can be ripened in the autumn by untying the plants from their canes, and laying them down sideways on a bed of straw, with the roots still in the ground. Cover the fruit with cloches. Water only the roots. They will not tolerate frost however. If a frost is forecast, the whole plants can be uprooted and hung upside down to continue to ripen in a greenhouse or indoors on a sunny windowsill.