Q When should I sow tomatoes for the earliest crops?

A It’s possible to harvest ripe tomatoes in the first week of June. The seeds we sowed in the Which? Gardening magazine trial on 5 February produced fruit in 13 weeks, but only when we kept them in a heated greenhouse until night-time temperatures were over 10°C in the unheated greenhouse. Those moved straight to an unheated greenhouse cropped a week later, but didn’t produce as many fruit at the first harvest.
Later sowings were more cold-tolerant. From our next sowing date on 12 February, we harvested tomatoes from all our hardening-off methods after 13 weeks. However, the more we protected the plant from the cold, the more tomatoes we harvested.
Waiting a little longer produced even better results. Seeds sown on 19 February showed little difference between any of our hardening-off methods, so there was no advantage in keeping these plants warm. All produced a decent crop after 13 weeks.

Caption: Wait until mid to late February to sow tomato seeds if you have an unheated greenhouse

Q Will stopping the tomato plant by removing the growing tip produce earlier fruit?

A If it’s early tomatoes you’re after, it’s worth stopping one or two plants after three trusses have formed. If you want a continuous supply of tomatoes throughout the rest of the summer, you should also grow some plants that after they've got six trusses.

Caption: Remove the growing tip after three or six trusses of tomatoes

Q Does removing tomato leaves to expose fruits to sunlight produce earlier crops?

A In the Which? Gardening magazine trial, removing leaves had mixed results. On our three-truss plants we had good crops early on when we didn’t remove the leaves, but our plants cropped for slightly longer when we removed the leaves, albeit with small amounts of fruit.
For six-truss plants, you’re better off leaving the leaves on, as the plant needs the energy from photosynthesis to keep producing tomatoes. We found these plants cropped longest and produced far more fruit than any others.

Caption: Removing tomato leaves has mixed results