Small greenhouse temperature control

[nematode]

This is a question for people with small greenhouses. Basically I have always worried about hot days like in May even April and having the greenhouse overheat. All it takes is less than an hour and all plants can be ruined.

I am wondering how people insure the temp is right every day with all of the fluctuations in sun light, wind, and ambient temp.

I am also wondering how people generally heat their greenhouses and what type of day/night air circulation they use to prevent condensation and things like that.

How do you make sure the climate stays inline? Do you have to be on top of it EVERY day or else there are problems?

Thanks.

 

[ChanellG]

When it's hot you don't need a greenhouse. I use mine for winter protection of delicate plants, but now I am thinking of shading it for cooler season crops. The one I have now will not survive another season, so heating and cooling it won't be a factor. If I have my druthers, I'll build another made of mesh and just cover it as needed in bad weather.

Since I use it to protect the plants that like warmth and humidity, I like seeing condensation. I just open it for a few hours during the day to give plants a break and to keep things from heating up too much. (I keep a thermometer in there) My mom ruined some plants by putting them in the greenhouse - she was trying to protect them from being over watered by rainstorms. Live and learn.

For heat, I tried jugs of water, but when that didn't work, I added a flower pot candle heater.

If yours isn't properly vented, you'll want to get a fan to circulate air and maybe even cover all or part of it with shade cloth.

 

[headfullofbees]

I have one of these:
http://www.amazon.co.uk/dp/B00CBUGPS8/ref=pe_385721_37986871_TE_item
It can be set for minimum temps, to keep the temp up. or max temps (which is what you want) to keep temps from getting too hot.
If you set it on max in your greenhouse, and plug a fan into it, it'll come on, when the temp gets too warm, and blow cool air around the greenhouse.
You can also get autovents, of which I have two, and automatic louvre openers, which are piston operated, and can be set to open greenhouse roof vents between 18C(64F) and 25C(77F).
http://www.amazon.co.uk/s/?ie=UTF8&...=aps&hvadid=3170882790&ref=pd_sl_7bl7vqsxd0_e

http://www.amazon.co.uk/s/ref=nb_sb...e+autolouvre&rh=i:aps,k:greenhouse+autolouvre

 

[CanadianLori]

In the summer I use automatic vent openers and fans to keep the air circulating. If it gets unbearable, out comes the shade cloth. I use mostly dc fans which receive their power from solar panels.

I have decided that I will also, once again, be building a solar water heater which will have it's water circulated to receptacles inside the greenhouse. The pumps will operate only when the sun shines and heats the water. I did this as an experiment and sadly underrated just how much this water moderated the temps. I took it apart and discarded it. That's okay, the next one will be sleeker ...

In the winter, well, I've got a few more weeks to wait before I start heating it and putting plants inside. I use a natural gas 20K btu blue flame heater to do this. Right now it is -9 during the day and -16 or so at night so it would not make sense to try to heat this area. Too much money for too short a day of sunlight- not quite 10 hours right now. Instead I have an area in my house that is lighted.

I can heat the smaller greenhouse by up to 8F using two Dietz kerosene lanterns - soo, as soon as the lows hit just above freezing, that gh will be utilized and it should cooincide with the 12 hours of daylight mark.

 

[headfullofbees]

I don't like kerosene (paraffin) or gas, I'm afraid. The smell.

 

[CanadianLori]

I don't like kerosene (paraffin) or gas, I'm afraid. The smell.

The Kerosene I use is called Kleen - it has very little smell. And natural gas, it only smells if you have a leak - and that smell is a good thing!

Do you use electric to heat your house?

 

[nematode]

Thanks for all of the helpful responses. I didnt realize the automatic vents are so reasonably priced. Sounds like shade cloth is a must though.

In the little time I have thought about it I would probably go with electric heat myself. I have wondered about two sources of heat for backup too. I suppose with lanterns I would not necessarily have to have a backup generator.

That solar water heater sounds really neat. I would really like to build things like that myself if I ever have time for it. Can you elaborate on what you mean about the size and temp regulation. I would like to get a reference if I could.

Having a greenhouse sounds pretty interersting. I am trying to decide if I should go with a small greenhouse or just keep using lights for my seedlings. I might have to try one in the future just out of the cool/gadget factor. Thanks again, happy growing.

 

[CanadianLori]

Some people use jugs or barrels of water to moderate temps. I am just going to kick it up a little bit by using the sun to heat the water.

 

[headfullofbees]

The Kerosene I use is called Kleen - it has very little smell. And natural gas, it only smells if you have a leak - and that smell is a good thing!

Do you use electric to heat your house?

Gas central heating with a condensing combi-boiler, which is stuck in a cupboard, out of the way, on the landing, with a door which remains closed, and a flue to extract unpleasant gases.
The smell is added for safety.
Here, the kerosene available stinks to high heaven, and the gas available for portable heating is usually butane or lpg (liquid petroleum gas) and the latter is terrible.

 

[CanadianLori]

We also have gas central heating. The furnace is quite large because of our low temps.