What's your location? If you are anywhere in the "winter" part of N America, you are a tad early for starting veggies. Unless you have perfect greenhouse conditions, it's more difficult to keep the growing plant from getting stretched and weak before it's time to plant them outdoors. Make sure you do an extra thorough job of "hardening them off" when it comes time to plant.

Having said that, your seedlings will grow with the natural amount of light you get through the solar pool cover. They would grow better with a stronger light source....but that really negates the whole idea of having a greenhouse, doesn't it? If you are going to put them under grow lights, you may as well leave them in the warm house until they get too big to do so and then you don't have to heat the greenhouse.

If you are able to successfully get the solar pool cover over your greenhouse and decide to put the seedlings out there, I would remove the bubble wrap already there to allow more light through.

I'm located in NE Kansas (5b)....... I'm starting annual flowers at the moment.... Although there are some onion seedlings in there.... This is the first winter I've attempted to use my 7 year old El Cheapo 6' x 8' HFGH......... 3K watt infra red heater with the bubble wrap & it maintains 55N/65-70/D with the heater on it's lowest setting...... However I'm looking for ways to reduce my electric consumption thus the cover...

FedEx has yet to deliver the cover today as scheduled.........

I live in zone 7a/b in southern NJ. This past summer is the first year that i decided to grow veggies in my greenhouse. My outside garden would either dry up or get overrun with weeds because i just couldnt keep up with it. That's why I wanted to start inside. I bought one of those wooden garden borders from Lowe's and it fit into my lean-to. Since the summer, I have 4 tomato plants still thriving from the summer. I pulled the other 5 because they took up too much room and I wanted to add other things. I picked about a dozen tomatoes this winter. The cucumber plants grew like crazy, and i had to add so much sting to tie it up because of all the vines they grew. I picked over 50 cucumbers over the summer through october. Then i had to pull them out, they were just over-running the inside of the greenhouse. This winter, currently I am growing peppers, green beans, and lettuce. I have a custom built (angle iron) East Southeast lean-to on my house so it gets full sun in the winter until about 1 or 2pm. I use a 240V heater and I have two box fans running. The heater runs to keep it between 50-60F. All of the plants seem to thrive pretty well in my current setup. This whole idea to start was really an experiment to see where it would go, thankfully it went well. I just use a flourescent shop light to light up the remaining hours.

f150 sounds good. How big is your lean to house and what is your covering?

Update: Pool cover (plus existing interior Charley's bubble insulation) has proven to be very efficient at retaining heat but I'm concerned about growth rate of the annual flower seedlings (started under lights in my heated shop & moved to the GH).

I do know that the bubble wrap allows 80% light transmission by itself, but I don't know what effect the pool cover has on light transmission..... Wyndyacre made a good point when I posted about adding supplemental light, in that one is defeating the purpose of using the GH if you're having to add lighting..... This is a valid statement, but I'm getting poor results & I'm sure a part of the problem is day length at this time of year...... (ie, lack of sunlight)

I might add that the mature plants (annual flowers & house plants) in the GH are doing very well while the seedlings suffer...... I have no idea why this is happening.... Don't they require the same amount of light as the seedlings?

melikeeatplants it's about 7' deep from house, 10' width and at the 7' depth it's about 6' and then rises to about 14' where it's attached to the house. I am using the clear corrugated polycarbonate panels. I got them from either home depot or Lowe's. It's not the prettiest greenhouse but the panels are still very durable and really no damage. I'll get a picture on here eventually... Steve