Heat or no heat for seedlings

Morning everyone!
Very excitingly my new greenhouse arrives tomorrow, which will be a heated greenhouse with power. My current one will remain unheated, and there is no possibility of electricity to this one.
I’d be grateful for your advice on seedlings. Thanks to those who have already cautioned me against paraffin heating in the new greenhouse! It will now have an electric heater.
I’ve always germinated my seeds on heat mats, located in the house in front of a large window. As soon as they’ve germinated I’ve moved them into the (unheated) greenhouse, and have just fleeced them if there’s been any particularly cold nights. This has always worked fine for me.
The heat mats will now move into the new heated greenhouse. Once the seeds have started, should I keep them in this greenhouse (just off the mats) or move them into the unheated greenhouse?
Thank you,
Kate
Very excitingly my new greenhouse arrives tomorrow, which will be a heated greenhouse with power. My current one will remain unheated, and there is no possibility of electricity to this one.
I’d be grateful for your advice on seedlings. Thanks to those who have already cautioned me against paraffin heating in the new greenhouse! It will now have an electric heater.
I’ve always germinated my seeds on heat mats, located in the house in front of a large window. As soon as they’ve germinated I’ve moved them into the (unheated) greenhouse, and have just fleeced them if there’s been any particularly cold nights. This has always worked fine for me.
The heat mats will now move into the new heated greenhouse. Once the seeds have started, should I keep them in this greenhouse (just off the mats) or move them into the unheated greenhouse?
Thank you,
Kate
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Hardy annuals will take far colder temperatures than, say, chillies or tomatoes but you wouldn't be wanting to waste heat mat resources on hardy annuals anyway when they'll get away just as fast on their own when light levels are better in March/April.
Half hardy annuals and tender plants, whether ornamental or edible, will need some warmth till after the last frosts in May.
I suggest you use the RHS website or the info on the seed packets or their websites to check which seeds and seedlings need heat.
"We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
Anything hardy is better left until it's warmer for sowing outdoors, or in a cold greenhouse/cold frame in March or so, and that makes it easier when it comes to finding room for them as they can hardened off very quickly and put outside until big enough to plant out permanently
I live in west central Scotland - not where that photo is...
"We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
Some half hardy annuals, such as impatiens, rudbeckia and salvia farinacea can be slow to start off so sowing early in a heated GH can be an advantage but others will grow too fast and be wanting to be planted outside before the weather is warm enough. Also they will fizzle out earlier at the end of the summer season.
Even after I had heating in my GH I learnt not to sow many seeds before March.