I would love to have a greenhouse...

I've just started gardening this year, and have caught a very bad case of the gardening bug.

I rent a townhouse in a rental complex, so I cannot put up any permanent structures. I casually mentioned my desire for a greenhouse to my landlady, and she suggested I could put a greenhouse up on our deck!

The deck is about 12' x 12' and is located above my garage, along the east wall of the house. It is shaded on the north by the rest of the house, and is exposed on the south and the west.

I have been looking at models like AFC Greenhouse Portable Greenhouse (10' x 6', Solaron cover, steel frame, front & rear screened vents, $279), Dreamhouse FH500DH (8' x 8', Gro-Tec cover, 4 screened vents per side, $249), and Plant-n-Grow (9' x 9', Gro-Tec cover, 12 screened vents, fiberglass frame, $399 with shade cloth).

I would put up the greenhouse in late March / early April and take it down again late June / early July. I want the greenhouse in order to start seeds for annuals (impatiens, coleus, petunias, etc) and some perennials. I do not intend to over-winter plants, or grow tropicals or anything like that. I just want a place to start my outdoor plants, and do not have any room inside my house for this.

I live in south-eastern Wisconsin, about two miles from Lake Michigan. Average temperatures in April are highs of 54 °F and lows of 36 °F. (May is 66/46, June is 76/56).

My questions are:

1. Will I be just wasting my time & money if I try to do this? (DH thinks so!)

2. Do 'greenhouses' at this price range handle the elements okay? I have been reading some earlier posts, and ran across one in which the purchaser was extremely unhappy with his inexpensive model.

3. Will I need to add lighting?

4. Will I need to add heating? I was not planning on adding any heating, hoping that the heat of the sun would be sufficient to keep the greenhouse warm enough for seeds. I do have easy access to 120V if it is really necessary, but I am sure these low-end greenhouses are not very well insulated.

I would love to be able to raise my plants from little seedlings, and experience the joy of watching them grow!

Thanks in advance for your help!

We'll see what other people think, but I think for the purposes of getting a little headstart on the growing season, greenhouses like those should work--anything that you could start in a coldframe you should be able to start in those too, I look at them as being an oversized cold frame. If you ever get into overwintering plants that won't survive your winters though you ought to upgrade. I wouldn't bother trying to heat it--the type of plastic covers that come on those don't provide much of an R-value, so you'll end up wasting a lot of energy and not raising the temperature much. Instead of a heater, you might invest in some heat mats to put under the flats of seedlings. As far as lighting--it sounds like this area might get some shade, and it's important for seedlings to have lots of light, so unless it's getting sun for the majority of the day you may want to look into getting some lights in there so that you don't end up with leggy seedlings.

The biggest problem I could see with this sort of greenhouse is that they're not going to stand up very well to wind or to snow load, so if you live in a very windy area or you get a snowstorm in April you may not be happy.

Jeannie63: I have two greenhouses, and neither one of them do what I need. They are too cold in winter, and too hot in summer. I am thinking about making a plant shelter on my east facing front porch, just like you suggested. For me, it is so hot here, I planned to make the greenhouse fabrics interchangeable so I can use shade cloth in summer and double 6mm plastic in winter. You can install grommets and make the side walls into curtains, sort of like shower curtains. You can thread the grommets onto a rod, or airline cable. You will have to figure out how to wind proof the top. The bottom can be fastened to the floor of the porch with battens, so the curtains won't blow away in the wind. To uninstall just lift the grommets off the holders, or unthread the airline cable.

You will need heat matts to start seedlings. You may need to suspend fluorescent lights to keep your seedlings from getting spindly. You can stack black painted bricks, or filled milk containers against the west wall, as a thermal collector. A temporary floor of concrete pavers will also help to hold the heat. I have made benches out of plastic sawhorses which are available at Walmart (Stanley). A few vinyl 2 x 4s (from the vinyl fencing department at Lowe's) maybe 6 or 8 ft long will turn the saw horses into a free draining bench. You can pile more thermal mass under the benches (like concrete blocks, or black painted plastic milk containers stacked.)

For heat you can use spot lights, or a small electric heater during stretches of especially freezing weather.