"JimM" wrote in message
...
I'm going to be optimistic and presume they are the Asters. The compost
came
out of a bag of J Arthur Bowers seed compost so I hope it wouldn't be
contaminated.
Knowing my luck though I'll probably spend the next few weeks carefully
nuturing some beautiful nettles

Jim
Don't worry about if Jim, with Arthur Bowers you can be fairly sure those
seedlings are from seed you put in. Asters do germinate very quickly at high
temperatures. It would certainly be worth your while to get a cheap soil
thermometer and check what the propagator's giving you and to try and
calibrate any control it has if it's adjustable. That will be fairly rough
and ready but you don't need a high degree of accuracy - reasonable
repeatability is helpful though.
These propagators are often a bit on the warm side. I hacked one
specifically for germinating Cyclamen by wiring in my own thermostat to
override the built in one. Do also bear in mind that thermostats only switch
off power, they can't cool the propagator so watch solar gain and preferably
site it in good light out of direct sun. Apply some shading during the
brightest parts of the day if needed (newspaper, fleece etc.)

Rod