There's nothing like the taste of homegrown, sun-ripened tomatoes. The scent of tomato leaves in a warm greenhouse takes me straight back to childhood and memories of sneaking out to pick a handful of golden cherry tomatoes before school. Many people grow tomatoes from plants bought from garden centres or from roadside stalls, but if you want to grow some of the more unusual and heritage varieties (many of which are very tasty) you will probably need to grow from seed. Don't be daunted. It is easy and very satisfying. The main challenge you will face is resisting sowing too many seeds unless you too intend to set up a stall at your garden gate.

Cordon or Bush

There are two types of tomato, cordon and bush. Cordon grow to about 1.8m and need supporting, either tied to a cane or wound gently round a strong string which is attached to something above the plant. Bush tomatoes are often grown in hanging baskets or pots and need no support.

 Tomato plant inside Rhino greenhouse, supported by canes

Growing tomatoes from seed

If you plan to grow your tomatoes in a greenhouse you should get the seeds sown in February in small pots or seed trays. Seeds for outdoor tomatoes can be started later, in March/April. They need to be at about 18C for germination, so place in a propagator or in a plastic bag on a window sill. Transplant when they have two true leaves, one seedling per 9cm pot. Keep potting on as the plant grows. 

 Tomato vines and Chilli Plants inside Rhino Greenhouses with man reading, dog, cup of tea

Planting out

If you do buy plants don't be tempted to put them straight outside. All plants, grown from seed or bought in, will need to be hardened off (left outside during the day for a week or two but returned to shelter overnight) before being planted outside. Whether in a greenhouse or outside you can plant tomatoes in the ground, in a growing bag or in a large 30cm pot. If you are growing cordon varieties put the supports in place when the plants are small.  


Caring for tomatoes 

  1. Cordon varieties need the side shoots pinching out regularly (these are the small shoots which appear between the branches and the main stem of the plant). 
  2. Check the supports, especially as the fruit begins to ripen.
  3. Water regularly - irregular watering can cause Blossom End Rot (the end of the fruit hardens, goes black and becomes sunken) or split fruit. 
  4. On Cordon varieties, remove the growing point once there are 7 trusses (groups of flowers) on greenhouse plants or 4 trusses on outdoor plants. 
  5. Once flowers appear, start feeding once a week with a high potassium feed such as Tomorite. 
  6. As the fruit begins to appear remove the bottom leaves to limit the spread of Tomato Blight or leaf mould. 



Grow basil plants in the same space as your tomatoes as these can help keep away pests and diseases, preventing them from ruining your tomato plants.


Saving Seed

If you grow some interesting varieties or if someone gives you some particularly delicious tomatoes, you may want to save seed for next year. It is easily done. Scrape the seeds out of a ripe tomato into a sieve and under running water remove as much of the gelatinous layer around the seeds as possible. Empty the seeds onto two layers of kitchen paper and spread them out to dry. Write the variety on the kitchen paper (if you know it!) and leave to dry for a couple of days. You can then simply fold the paper and store in a labelled envelope in a cool, dark place until next spring – but do make sure you store somewhere mouse-proof. You can then lay the paper on damp compost, cover with a thin layer of compost and start the whole process again. The only seeds you cannot save are F1 hybrids. They will not come true from seed, so you won’t get the same fruit next year.



  • Blossom End Rot or split fruit are the result of erratic watering.
  • Tomato Blight is a disease which is much more common in wet conditions and affects outdoor plants much more than greenhouse plants. The leaves become brown and mottled brown patches appear on the fruit. The plant should be disposed of immediately (not composted). 
  • Tomato leaf mould is a fungal disease which is more prevalent on greenhouse plants. Good ventilation and regular watering minimise the risk. 

 Tomato Blight

Written by Ruth Darrah of NSG