[Bernard]

I have used a Vitapod propagator for the last few years.
Having decided to start my toms earlier than usual, they are now strong seedlings but I suddenly find that the temperature in there is deceptive.
With the sensor in the compost, the temperature is recorded at 19C. But I find the the air in the propagaor is only 14 at best, 12 when the ambient was freezing and in spite of having horticultural lights and several layers of bubble-wrap over the top.

So the roots are at the advised temperature, the top growth is not.