heating/cooling greenhouse

I just got a solar greenhouse in late spring. We are in the process of getting water and electricity to it and before we made some final plants, I thought I would see if anyone is using a heating/cooling unit that they like. I don't want to spend a lot of $$ but so far in late spring the temperatures got to 30 degrees in the greenhouse and in the summer it's really hot - 120 degrees. The 30 degree temps didn't do any harm. I'm still learning how low I can go. I had moved my tropicals in the greenhouse and we got down to around 28 degrees. I didn't have any thermal mass in the gh at that point, but I guess because there were no cold winds and there was not frost I got by. Anyway, in zone 6 a I'll get pretty cold in the winter, and I want to use the gh in the summer. The gh has vents and a window and door. I just need something to push the air around. Any suggestions would be appreciated. Thanks

it really depends on the CFM (cubic feet per minute) requirements you need for your greenhouse. that depends on the size of your greenhouse and the amount of air movement you want. our site has a technical page at http://www.igcusa.com/Technical/fan-shutter-sizing.html that includes a formula for sizing an exhaust fan as well as other information. If your just looking for air movement, you may also want to consider HAF fans. these are circulation fans that help to stabilize temperature within the greenhouse. these fans are much smaller however, and don't move much air compared to the exhaust fans.

I'm near you. I heat with propane, 2 units. Cooling is multidimensional, exhaust, intakes, shade cloth, mist, sometimes fogger.

What size is your house?

I installed eight 55gallon metal drums along the north side of my GH. It raised my nightime temps by ten degrees. Of course with tropicals you will need to install some type of heater. Here's a link to thread. Good luck!

http://davesgarden.com/community/forums/t/790772/

Thanks for the replies. The greenshouse is 8X8X15. Here is a picture. This one is from the online store, but mine looks just like it. There are two vents on the top that open by solar heat. The vents have cylinders that have mineral wax that expands to open or when it cools off it closes. I love the greenhouse so far but the simply solar greenhouse website doesn't give a lot of info on heating and cooling. I have a couple trash cans filled with water to help with temp control, but I am finding in the summer it's too hot. The misters help alot but I think I'll just try a fan to circulate the air, maybe that will be enough to cool off. I'll also just try a space heater. I appreciate the comments - I had my husband run my water and electric right into the greenhouse. If this first approach doesn't work, I'll try something different.

Another question - I have started some tomatoe and cucumber seeds from Johnny's seeds, for greenhouses. I keep seeing that the tomatoes aren't very good in a greenhouse. Don't they taste better than store bought tomatoes in winter? or do they taste like the hothouse tomatoes in the grocery stores? thanks

I don't think those vents are going to be enough. I would install some power venting attached to thermostat. Maybe a shade cloth for hottest months. Here is some of the best prices I have found. They also have a venting calculator.

http://www.greenhousemegastore.com/

As far as tomatoes I have had excellent results this year. I'm growing Fantastic, Mortgage lifter, Boa, Early girl, Roma, And beefsteak. All are the sweetest most perfect fruit I've ever grown. I have a row of eathboxes down the center, and they have produced the best by far!!!

Keith,

Thanks. That is exactly what I was looking for. The vents were not enough this summer and I wanted to look at a way to move the air around and help the venting out. Thanks for the tomato info also - I've started my winter greenhouse seeds this weekend!

Hello:

I am a newbie here, and just got our greenhouse finished. It's just a small one - the Enthusiast. It's so pretty, and I don't want to spoil the aesthetic beauty with a cover. Have any of you used the window film? I have been researching it on the internet, and am just not really sure how to go. Living in central/western Florida we get very few cold nights below zero, so I can handle that aspect, but already the temperature yesterday in the greenhouse was 112 degrees. I sure would love to hear from you guys on this subject. I have been reading your posts for hours and hours, and have gotten wonderful tips from you. Please help!

What kind of ventilation did you get with your GH? Sounds like you might need to invest in some vent openers and fans, in a climate like yours I don't think shade cloth or window film will do much if you don't have good ventilation along with it.

I have 2 roof panels that open and 1 on the bottom middle of the back. Plus I have the door open. I have added a fan, and it has helped a little, but I know I need to do more.

Forgot to mention - I have an automatic vent opener - ME. I am out there all the time, so I don't need any fancy equipment. It's great to be retired! ;-)