greenhouses, cold-frames, hoop-houses, winter-sowing, wha??????

[gladahmae]

I'm in zone 5a, and over the past few years I've tried wintersowing (gardenweb thing) and while it works pretty well for me for flowers, i don't have as good of luck with veggies. I'm contemplating a greenhouse or a cattle-panel-style greenhouse to extend our growing season a bit, and just as a fun hobby.

But then I start researching and reading. It's overwhelming! And so much of the methods/advice conflicts! Fans, heat, misters, ventilation. And of course, the people who seem to know what they're talking about *only* recommend greenhouses that cost several thousand dollars, and then need modifications to withstand things like wind and snow.

A little help?

 

[Oregon Blues]

You have to go out and knock the snow off the greenhouse, no matter what it is made of.

The easiest thing to do, if expense is a consideration, is to do a sturdy frame with a removable cover and take the cover off at the end of the fall season and put it back on in the spring.

You can use the greenhouse to extend your growing season by several weeks in the spring and perhaps as much as 2 months in the fall.

If you want to grow all winter in a cold climate, you will have to provide heat. The greenhouse will be warmed by the sun during the day, but it cools off quickly once the sun is down.

If your climate is warm, you probably need ventilation so that the greenhouse doesn't get too hot and bake your plants. Shade cloth over the greenhouse will also help to keep it from getting too hot.

I use high tunnels and take the cover off during the middle of summer when it is warm enough for the plants outside. Then the cover is also removed in the winter and stored inside. When weather is in between, I raise the sides during the heat of the day and then cover again for night.

 

[Oregon Blues]

Additional comment: you can often substitute work for money, which is what I do with my high tunnel. I babysit it. If you don't want to spend the time adjusting the cover, then you spend a lot of money and get a fully automated system that takes care of itself, but costs a packet of cash.

 

[gladahmae]

what about the tunnels people put on raised beds? same concept as a high tunnel, but removable for the summer? what special considerations do those have?

 

[stone_family3]

I'm in Ohio and I've seen several people use A-frames so the snow falls off easier. I've seen a lot of people make them out of materials like pvc that they can just fold up in the warmer months.

 

[Blackcrest]

I can understand how you feel. I myself have come across the high price green houses. And to be honest it well out of my price range. I started off my garden in the house. you can go to wal-mart or I like the little local hard ware store and get the multi pot enclose containers and start your plant, and spring gets closer you can plant your plants in the garden area and use old milk jugs to cover them till warmer weather. but if you want a green house and I did. you have a few options. you can use pvp pipe about 30ft long and bend them in a slight arch and cover them with plastic. here's a link

http://www.greenhousemegastore.com/category/plastic-greenhouse-film

Now i just went out and actually built my green house, I got lucky and someone was selling the A frames cheap. But my first house which worked great even if it wasn't as big as the one i just made was actually made of bamboo and plastic. I used a buddy heater in the cold months on low setting at night and turn it off durning the day.
http://www.tractorsupply.com/portab...e-radiant-portable-heater-18-000-btus-2133493

As for cold frames look at craiglist for windows. or stop buy homes they are tearing down and ask for windows. that teh best way. i got a nice bay window in its frame i use for a cold frame. When money is tight, some times it best to think out side the box. and think of it's function and get things that wil work till you get what you really want. I hope i helped a little bit.

 

[bluenkimchi]

You can try a carport type with the the metal roof for a frame, then just modify it. They are sturdy and wind and snow safe. You can cut and modify the roof with windows for sun light, then use thick greenhouse film to cover the sides.

 

[Thistlelady]

I live in Colorado. Zone 5b. I like the cold frame with windows you can remove in the hot summer and replace when the winter sets in.
my cold frame that we take the windows off in early June and replace in mid to late Sept. Depending on the year it can add 4 months to my growing season. I can plant at the end of March (Mothers day without) and get fresh veggies thru Oct. Sometimes as late as Thanksgiving.

 

[HandsomeRyan]

My day job is (among other things) managing a 6000²ft research greenhouse. You can put me solidly in the "if you want a real greenhouse be prepared to spend big money on it" camp. I think cold frames (as someone else suggested) are a great compromise for those on a budget or who just want something to play with as a hobby.

Greenhouses require more consideration than simply building a clear structure and filling it with plants. You need to think about pest control because greenhouses are very good at letting pests in but keeping the kind of things which naturally keep pest populations in check out (eg. I get a lot more aphids in my GH than I get ladybugs to eat them). I don't know what your feelings on spraying pesticides are but there will likely come a time in your greenhouse where a pest population will reach a level where you either have to spray something or discard the plants. Not all pesticides are labeled for greenhouse use and this is something to consider. (I am a licensed pesticide applicator and there is a several hundred page book sitting on my shelf of the rules I have to follow)

Ventilation is another huge concern. Not just for keeping the chamber at a steady temperature but also providing air circulation to help prevent fungal and bacterial rotting problems. Commercially produced greenhouses will have both thermostatically controlled ventilation fans which draw out the hot air on sunny days and draw in fresh (hopefully cooler) outside air, but they will also have what are know as "HAF" or horizontal air flow fans which move the warm air around inside the greenhouse. These run pretty much all the time. There are other concerns such as heating as well. Much like the cooling, heating is best thermostatically controlled. Greenhouses are terribly inefficient because the requirement that they be clear means you can't do too much to insulate them. My greenhouse has both radiant steam heat and forced air gas heaters and all I can say is I'm glad I don't pay the utility bills here in the winter.

I don't mean to discourage you as I think it is great that you are interested in building a greenhouse I just want to make sure you understand that there is a lot more to a greenhouse than just a clear building that stays warm in the winter. I didn't even touch on things like shade cloths, humidity controls, thrips netting, or supplemental lighting.

If you have a local garden center which has a proper greenhouse you might stop by and just ask one of the employees to show you some of the greenhouse systems for heating/cooling/air flow. This will give you a better idea of what the pro's use and what you might need for a backyard setup.

Best of luck whatever you decide. I love having access to a greenhouse for starting my veggie plants and stuff.

 

[gladahmae]

Thank you for that very detailed post! Pests and airflow are things that I had sort of considered, or ya know, thought that I would need to eventually look at. I'm not looking for a year round thing by any means....just a jump start on our shortish growing season, and maybe having tomato plants last past September.

Cold frames seem to be the way to go budget wise so I'll have to start keeping an eye out for cheap or free windows.