Growing Tomatoes from Seed

Growing tomatoes from seed is a little more tricky than buying tomato plug plants or small plants from the garden centre but well worth the effort.

Tomato seeds need to be sown in new compost, just below the surface and kept in a warm place for the best chance of germination. It is quite normal for one or two seeds to fail, but if more than 25% fail to come up, there is something wrong with the seeds or the way they’ve been sown.

Sow a few seeds in a small pot or propagator just below surface 1/8 inch deep. Place pot in a saucer of water or water propagator from below and cover with cling film or lid.

Keep in a warm place (around 18 – 21C, 65 – 70F) and as soon as the seedlings appear, put them in a light position (not too warm around 15 – 18C) to stop them from becoming too leggy.
After their first true leaves are growing, transplant the seedlings into individual small pots so that the seed leaves are just above the soil level (see below).



John Innes No.1 or any potting compost is good because it contains the mixture and nutrients suitable for young plants. It’s also a good idea to add a little of the seed compost to the transplant mixture (when the seedlings are transplanted into their own individual pots) as this will help the roots become established.

Using a propagator is best if you are sowing a lot of seeds. The humidity in the lid area also helps the seedlings discard the seed shells.
If the seed shells (husks) remains stuck to the seed leaves so that the leaves cannot open, gently wet the shell with a blob of water and hopefully the leaves will open and the shell drop off … it is best not to pull it off.

The idea is to grow seedlings so that they develop plenty of leaf growth rather than height. This is achieved by keeping them in a light position without giving them too much water or heat (not above 20c, best around 16-18c) or they will become too leggy and not be able to support their own weight.

A heated propagator can be very useful to keep small plants from temperatures that are too low.