Part of the Gardening Owl Grow Your Own collection. Practical growing advice for gardens and allotments.
The essentials at a glance
Tomatoes are tender, sun-loving plants. They can grow in a greenhouse, a sheltered sunny garden or generous containers on a patio. Greenhouses often give a longer, more reliable season; outdoors, warmth and shelter matter.
| Step | Typical timing | Important detail |
|---|---|---|
| Sow indoors | Late February–March for greenhouse crops; late March–early April for outdoor crops | Provide warmth and strong light |
| Plant into final position | After suitable temperatures and frost risk have passed | Harden off outdoor plants first |
| Harvest | Summer into early autumn, depending on variety and weather | Pick when fruits are ripe |
The dates above are broad guides, not a promise for every region. Read the packet and watch local overnight temperatures.
Choose bush or cordon tomatoes
Bush (determinate) tomatoes usually stay compact and are often easier for containers. They generally do not need their side-shoots removed. Cordon (indeterminate) tomatoes grow tall, need a strong support and are normally trained to one main stem, removing side-shoots as they appear. Check the label before pruning: the wrong approach can reduce the crop.
Sowing tomatoes from seed
- Fill a small pot or modular tray with peat-free seed compost and water lightly.
- Sow seeds according to the packet and keep them warm, at about 18°C for germination.
- Once seedlings emerge, provide bright light and do not leave the compost saturated.
- Pot on when plants have true leaves and roots need more room.
- Harden plants off gradually before moving them outside.
Planting in pots or beds
For containers, use a substantial pot with drainage holes: a roughly 30–45cm container for one tomato is a useful starting point, depending on plant vigour. Use good peat-free potting compost. In beds, choose fertile, well-drained soil that retains some moisture and incorporate mature compost if needed. Plant deeply enough to encourage roots along the buried stem.
Improve outdoor soil with our soil preparation guide. If you are short of space, read Vegetables in Pots.
Watering and feeding
Keep moisture as even as possible. Large swings between dry and wet compost can contribute to splitting and blossom-end rot. Aim water at the base rather than regularly wetting the foliage. Container plants may need daily checks in hot spells.
When fruit starts to develop, container plants generally benefit from a high-potassium tomato feed used according to its label. Plants in rich ground may need less. Open greenhouse vents during warm weather for airflow and access by pollinators.
Training and pruning
Tie cordon stems loosely to supports and remove side-shoots that develop in leaf joints. Do not routinely remove side-shoots from bush varieties. Remove badly diseased leaves promptly and avoid overcrowding, which traps humidity.
Common tomato problems
- Blossom-end rot: dark sunken fruit ends are often associated with disrupted calcium uptake caused by uneven moisture, not simply a lack of fertiliser.
- Fruit splitting: commonly follows rapid changes in water supply.
- Blight: outdoor plants are vulnerable during suitable wet conditions; remove severely affected material and follow current local guidance.
- Flowers without fruit: low light, temperature extremes and poor pollination can all contribute.
Harvest and further guidance
Harvest ripe fruit gently and use it fresh. For other productive summer crops, see How to Grow Courgettes; for watering technique, see Garden Watering; and for trouble with vegetable plants, see Fruit and Vegetable Diseases.