By Steveg1966
West Yorkshire,
United Kingdom 
My greenhouse heater has packed up and I have some leek onion and cabbage seeds that have not germinated yet will they be ok for a few days until I can get another heater.
11 Feb, 2013
Answers
A heat mat is far better for germinating seeds in your greenhouse than having a greenhouse heater.
If you can get one with a thermostat, use the probe in the compost, set to about about 65'f and your seeds will germinate in about a week.
Greenhouse heaters can then be set to about 50'f to keep things ticking over.
11 Feb, 2013
yes they will. I dont usually start mine off in the heat anyway.
11 Feb, 2013