Somewhere between a penny and a hundred dollars per day. Too many variables to tell you. Size of greenhouse, type of covering, how well constructed, type of floor, outdoor temperature, type of heater, heating to what temperature, etc. all factor into your cost of heating the greenhouse. It is not cheap.

You could use free energy, expect there are initial costs.

A solar panel can charge a battery during the day, and the battery can power the heater throughout..

We put up the porable greenhouse yesterday. I thoght it was supposed to be twenty degrees higher than the outside temp. It is the same temp. as outside. What plants can survive in thirty degree temps? What is the purpose of this tent-greenhouse? Must we use the heater? How about the cold frame? When do you do that? As you probably figured out this is my fist year for the tent-greenhouse. Someone please write back. thanks SharonBender

A greenhouse needs to be pretty secure so that greenhouse gases don't escape too much.

Since we live in PA, the temp doesn't need to be regulated much unless your plants don't mach the hardiness of the area, or you have an aquaculture tank with fish.. Most crops are planted around spring and summer.

I don't think there is much use of a greenhouse in PA, because the weather gets nicer starting Spring. It depends what its purpose is. Like are you growing food?

Usually, people have raised beds, with a fence around it to keep rabbits and deer from eating the crops.

There is a popular book called "All New Square Foot Gardening" if you are interested in growing food.

Thank you for the rsponse. yes, I do want to plant food. Don't I first have to plant the seeds in small containers, then take them into greenhouse when the seeds develop? Consider that it still goes down to 30 at night can I leave them in greenhouse all night without heater? thanks SharonBender

Frost at night is about to end soon. I think crops are planted after or little before the frost ends.

People can germinate seeds during winter to give them a head start for spring. The seeds can be planted in small seed starting trays found at garden stores.

Using heater just to stave off frost is costly, unless you install solar panels.

Chris, I love your idea of using solar energy. Can you provide more info or a link for some specifics on this?

Thanks!

I found this link.

http://www.wholesalesolar.com/batteries.html

I just googled 'batteries for solar power'.

Some months ago, I saw Youtube videos where people connected their solar panel to a big battery similar to ones found in cars. They charge up during the day, so that they could be used at night.

to have a working timer in greenhouse, heater plug has to be connected to ouside electric extension cord (heavy), then connected to timer (2 or 3 inches in diameter, heavy), then to plug in laundry room. By the time we plug all this heavy stuff into wall it tends to slide out a small amount and the timer does not work. We presently use electric tape to hold up the timer before it enters the outlet, but it does not hold very long. Any ideas that would help? Thanks SharonBender

Would'nt the structure itself stop frost from collecting on the leaves? I have my seed flats that have germinated under small greenhouses that open like an umbrella. You can zip or unzip the front. It has a pole you pound in the ground to keep it from winds blowing it away. I know in a cold spell I will have to bring them in, but, above 32F they should be fine.

I have not used the heater for about a week now, because temps are staying over 32 degrees, even at night. The already planted (small plants bought at store) are growing fine, but the new seeds i have planted have not come up, WHY? It has already been three weeks since I had planted the new seeds and I have been watering them daily. Does it get too hot in there? Please help! thanks

"We put up the porable greenhouse yesterday". What did you want to grow, why did you purchase this ?

You have a cold frame, ( no heat or electricity) It will be most useful when growing plants that tolerate your cold temps, but you just need a little protection from wind. Unless you run a safe ( not an extension cord) electic line out to the GH - And a freeze proof water line, you will have a limited number of plants that will grow in the cold of winter. The inside will be a few degrees warmer than the outside at night - maybe - and during a sunny day will get hot, and probably need vented.

Some seeds need warm soil to germinate, google seed starting and there should be a list of which seeds need warmer conditons to start. Once started inside, and when temps are not below 40o then you can harden off the small plants in your cold frame. Just be sure it does not get too hot duirng the day.