How to use a greenhouse?

[newcook]

I have started receiving seed catalogues and it got me thinking.

Last year I started seed indoors and slowly moved the seedlings outdoors a few hours at a time, finally planting directly in the garden. But all this time I've had a greenhouse in the yard (it came with the house) which I have never used.

I have no idea how to use the greenhouse. Mainly I have no idea when it is safe to move the seedlings to the greenhouse. Are there temperature or weather guidelines?

I live near Montreal, Canada if that makes any difference. I would really like to use the greenhouse because the planting season is so short here and I would really like to get the plants growing as soon as possible.

[donleyk]

Have you checked any postings over on garden web? You may end up wading thru a lot of material but that's where I'd start.

http://www.gardenweb.com/

[charley]

First thing I would do is buy a thermometer to keep in the greenhouse. Check throughout the day so you have a better idea of the conditions in there.

What zone are you in? I'm in 8b. I started my tomato and peppers the first of February. Once the seeds germinate I move them outdoors to the cold frame. It stays about 10 degrees warmer than the outdoor air temp. On nights when it gets below freezing I toss an old flannel sheet over the cold frame.

[RiverFarm]

We live in Zone 7, and I transfer my seedlings to my greenhouse once they get their true leaves. When it's going to be cold at night I have a small heater that I plug in, to prevent the temperature from dropping below about 45°. I really like the greenhouse for this purpose because it helps avoid spindly stalks, since the light comes from all around the plant rather than from a single fluorescent bulb source.

I also use my greenhouse to store implements, potting soil, seed trays and other garden material. There's a table that I can use for repotting, although I tend to do that outside in my arbor where I have a sink.

In the summer the greenhouse gets too warm to be of much use for anything but storage, but it's still a focal point for my garden and I'm glad to have it!

[Valerie226]

Depends on how hardy the seedlings are... we start in the basement, move to a greenhouse. cool weather crops like broccoli lettuce etc need to harden off before going into the ground. most flower seedlings need to stay warmer and inside, as do warm weather vegies like tomatoes, corn.
the greenhouse gets very warm even when it's still cool outside, so you need to monitor and make sure things don't get either too cold at night or too hot during the day, either of which will kill things. we usually start to move things to the greenhouse in march. may still frost at night but not hard enough to kill anything. you need to water plants in a greenhouse much more often than you'd think... tiny pots, warm temps. in spring if it gets sunny we open the greenhouse lid to let out the heat.

[Gumbeaux]

Some greenhouses in our area use heating mats. There are both commercial versions and home owner versions (like below) of these.

[newcook]

donleyk, thanks for that link. It looks like I might be spending a lot of time over there.

charley, I'm in zone 5a. I'm not sure if the Canadian zones correlate with the U.S. zones. I have bought a thermometer but have not installed it yet. I'm a little jealous of your climate, planting so early must give you a wonderful crop, maybe even two crops. Wow!

RiverFarm, if I understand correctly I have to watch the temperature and wait until I get over 45 degrees. Is there also a maximum temperature when I need to pull the plants out? There is no electricity out there, so I can't plug in a heater.

Thank you all so much. Now I can't wait to go out there and install the thermometer to see when it gets warm enough. Ha!ha!, I think I need to start my seedlings first though. It is supposed to be mild later this week, hopefully enough snow will melt to give me access to it. The week ahead will only have temperatures between 17 and 34 so I have a while to go yet.

[newcook]

Valerie226 and Gumbeaux, you must have been posting while I was typing. Do you all have electricity running to your greenhouses or are you running an extension cord?

Valerie226, thank you for sharing your experience. How hot would too hot be?

Gumbeaux, is that this years planting? I did not realize I could start so early.

I got 2 table top grow lights for Christmas which I intent using to start the seedlings. Right now I have geraniums under the lights which I brought inside in the fall. I have losing so many plants each winter, but without the grow lights, the geraniums became really stringy.

[Valerie226]

Our greenhouse is not an actual house, but 2 large wooden structures with clear angled lids that face south. we can open the lids to a couple levels depending on how warm it is. no electricity. this is real simple stuff.
we use a heat mat in our basement and grow lights.... some seeds need warmer temps to germinate. we have lettuce and broccoli started in the basement and will move them outdoors after we get back from vacation in mid march. not every year is the same. this is a very mild warm year here and if we weren't going to be on vacation we'd probably be startign more things.
Too hot...?? well if the sun is shining even with the air temp maybe in the 50's it gets pretty warm. tomatoes would be fine, but broccoli and lettuce might wilt, if their pots dry out. depends on the ventilation, exposure, how big the pots are, how big the plants. we live in western washington, a pretty mild climate with cloud cover that keeps it from freezing hard. a lot is experimentation based on your site, how much sun, and what you're trying to grow. It would almost never get as low as 17 here, we are more likely rainy and 40. we plant cool weather stuff outsiode in march many years.

[charley]

Some greenhouses in our area use heating mats.

Heating mats are only used for germination of seeds.

[barbara-cook]

A greenhouse! I am SOOOO very jealous!

Almost every year, I start some seeds inside. But it usually never works out because I have no south facing windows. And I don't really have the money to invest in lights, heat mats and all the other stuff. So as a result my veggie garden has gotten smaller, and in fact last summer was just a few pots on the patio.

The deer herd around here must have found the plants because once they blossomed, they were muched and that was that. Now, a greenhouse would keep the deer out!

Wow. I am so jealous.

[RiverFarm]

Barbara, comes a time when plants do have to leave the confines of the greenhouse and live in the garden. We have fencing around ours, with a strand of electric wire, and it does keep the critters out. They chomp on our fruit trees, which are outside the protected area, but not on our veggies.

[newcook]

Ugh! We are getting more snow.