Ideal Temperature For My Plug Plants

Hello,
Can anyone advise myself what would be an ideal temperature in my greenhouse for the Trailing Petunias that I have purchased.I have had them on my window sill for a week or so,but wife wants them out.I have planted in small pots today.But would be grateful of any advise for a successful summer show.Cheers.

 

No indication of where you live, but I think you are way too soon with petunias. You'll need to keep them frost free until you plant them out and then only plant when all danger of frost is over.

 

I agree with Dave. Even an unheated greenhouse isn't going to be frost free at night yet for a while. I recon that an unheated greenhouse is, at best, only about 3C to 4C warmer at night than outside. And if you have a long spell of daytime frosts, the greenhouse will be no warmer at all.

Two days ago it was -7.5C overnight here, which would have produced a frost inside the greenhouse if it wasn't for the fact that I have an electric heated on a thermostat.

 

Thanks for the info.I received these plug plants two weeks ago,and my intentions was to take them from my utility room which is sitting around 20 degrees for the last two weeks.I am going to transfer them into my greenhouse and supply heat with a gas heater thermostat controlled.I just would like to know what temperature I would need for the overnight periods ?.I live near John O groats so yes its still frosty here.I usually plant into containers/baskets in April once establishrd and continue to care for them in the greenhouse with less heat then of course.I am also catering for buzzie lizies as well ,but these are in window sill in the living room,for at least another week,to give a better chance of survival.Cheers.