Spalding Guardian Gardening 11 April 2013
The difficult spring is starting to show itself in trouble with tomato seedlings and young plants. The packets usually tell us to sow the seed in an unheated greenhouse in late February and early March, so the plants are ready for their final potting up in containers and growing bags when they are about 20cm tall, generally at the end of this month or the beginning of next.
This year, however, the low temperatures and, during mid-March, lack of good light has played havoc with germination and healthy growth. Even if there have been a reasonable number of seedlings produced from the early sowing, many have damped off, the cause being cold, wet compost and poor daylight. If you’ve been lucky enough to get your plants to a size large enough to pot on from the seed tray to small plant pots, the oldest true leaves are now curling inwards onto themselves, showing that although day temperatures in the greenhouse may have been adequate, the difference between these and night-time ones has been so great that the poor things have been placed under quite a strain. Mine have even turned blue, indicating that both day and night temperatures have been too low. We can only hope that the weather turns more seasonal in the next week or so, then problems such as these should right themselves.
Thin, straggly plants with large gaps between each set of leaves are also a sign of poor natural light. Hopefully, as the sun gets stronger and we see more of it, this should not affect the formation of the first flower truss too much, but allowing as much space as possible between plants at this stage will help to prevent this. If your plants are really sickly after this appalling spring, though, you may find it better to discard them and make another sowing, assuming you can afford it. Tomato seeds sown now should catch up rapidly, enable final potting only two or three weeks later than those sown earlier, and cropping very little later than normal. And if all else fails, you can always cheat and buy in plants, which in the circumstances may turn out to be a wise move.
This piece originally appeared in the Spalding Guardian