When is it going to get warm?

I spent most of this morning transplanting my tomatoes from their seed pots up into individual pots. They need it to allow them to grow on faster but, I wondered when it was going to get warm.

Those of you who have looked at the Raspberry Pi part of this site will know that I’ve been measuring and recording various temperatures (outside, in the polytunnel and in a barrel of water in the polytunnel) to see whether a barrel of water in the tunnel can improve (i.e. raise) the temperature in there.

However, what it shows is that, even in the warmth of the polytunnel, temperatures are really struggling this year. Not only did we have various “Beasts from the East” during March, but the weather in April has been damp and miserable. Wet and little or no sun. Whilst I haven’t got any data for previous year, what’s obvious from the figures for this year is that rather than trending upwards, the average daily temperatures for early April are on a downward slope and, unless we get some decent sun in the next few days, it doesn’t look as though its going to get any better.

This affects my tomatoes. Normally, by now, I’m sure I’ve stopped taking the plants in and out of the greenhouse, relying on the daytime sunshine to leave residual heat in the greenhouse to keep the temperatures above 10C without adding any extra heat. However, in the past week, the temperature in the polytunnel hasn’t crept above 10C even in the daytime and the nighttime temperatures have drifted towards 5C.

Tomatoes don’t like being cold and not being adequately warm at the start will affect them throughout the year. So I’ll have to continue bringing them in and out of the house for a few more days yet. This could mean that I’ve got lots more trays to carry through but I’m afraid I’ve identified the strongest plants and only those will be molly-coddled, the rest will have to tough it out in the greenhouse.