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Author Topic: Anyone gardening in a hoop house?  (Read 11823 times)

Offline showme714

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Anyone gardening in a hoop house?
« on: March 05, 2011, 08:15:49 pm »
I have built a 20' X 27' foot hoop house. I am awaiting the UV plastic to skin it next week. I was wondering if anyone here has a hoop house? I am interested in ways to economically heat it in the winter.

Offline AllenF

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Re: Anyone gardening in a hoop house?
« Reply #1 on: March 05, 2011, 09:29:44 pm »
What are you planning to grow in it this winter?   

Offline showme714

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Re: Anyone gardening in a hoop house?
« Reply #2 on: March 05, 2011, 10:25:34 pm »
What are you planning to grow in it this winter?   

I want to continue tomatoes, beans, cucumbers, squash, etc. I have been researching ways to use solar heat, compost, etc to heat it at night. I really have a zero budget for heating but am willing to put in sweat equity to make it happen if I can come across the right sustainable method. I have my hydroponics to fall back on in the house and garage on a much smaller scale.

Offline Humanbeeing

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Re: Anyone gardening in a hoop house?
« Reply #3 on: March 07, 2011, 10:35:28 pm »
I'm sure you are aware of the different ways to retain heat. They work well, up to a point. But, as soon as the temp starts dropping towards freezing, nothing will keep a hoop house warm. If you run a heater in the cold weather, you might as well heat the entire county! The main thing I would do, is build the north wall out of block filled with dirt. Paint it black. Half of the east and west walls should be insulated also. Double covering with a blower is a must. If you did that, you could probably run a small gas heater that would keep your plants growing slowly. As far as tomatoes, peppers and other heat loving plants, look for them to start slowing down almost immediatly, as it gets coller and cooler. I would concentrate on carrots, onions, spinach, cabbages and such. Cool weather crops. Hoop houses are not really meant for prolonged winter use for heat loving plants.
My little greenhouse keeps me in onions and carrots all winter here in Idaho. You can't dig them out of the frozen ground in the winter, except in the greenhouse. I have cabbages, bok choy and such blooming in February.
HELP! I accidently used Drone eggs with the Hopkins method and I got Drag Queens!!!

Offline BlueBee

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Re: Anyone gardening in a hoop house?
« Reply #4 on: March 08, 2011, 02:26:35 am »
The guys over in East Lansing seem to think hoop houses work in Michigan!  I’m skeptical, but here is a link to their hoop house site. 

http://www.hoophouse.msu.edu/index.php?q=home

I haven’t read all the stuff, but basic physics suggests some difficulties with hoop houses.

Energy in is probably not the problem since the heat from the sun is probably about 100 watts/sq foot.  Your hoop house might collect 54kilowatts per hour on a sunny day (almost 200,000 BTU/hour). 

The problem is Energy out.  There is little to no insulation value in single walled plastic.  Those 200kBTUs/hr would quickly escape on a cool night.

You probably have to do as humanbeeing suggests and/or add a natural gas heater like most greenhouses use.  The good news is the USA is drowning in natural gas right now so maybe the price is right.

Offline showme714

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Re: Anyone gardening in a hoop house?
« Reply #5 on: March 08, 2011, 06:25:01 am »
Thanks guys for your suggestions but I think I'm going to try and build a Rocket Mass Heater. Check out the videos on Youtube.com if you've never heard of them. I am currently reading a book on the subject. It's cheap to build and if I do it right I should be able to heat all winter with less than a cord of wood. Normally the winters aren't that rough in Metro Atlanta and daytime won't be a problem, I'm sure.

Offline Countryboy

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Re: Anyone gardening in a hoop house?
« Reply #6 on: March 08, 2011, 11:23:46 pm »
I have a 12X30 hoop greenhouse.  I found that cooling it was more of a concern than heating it.  They get really hot if you get much sun.

You only really need to worry about heating it to keep it above freezing.  (Or to get seeds to germinate, but you can germinate them in your house and move them to the hoop house after they are seedlings if necessary.)  As long as your temps are above freezing, I wouldn't worry about heating it.

The Amish greenhouses have already started plants in their greenhouses.  Most of them have large woodburning stoves to heat their greenhouses, but they will be starting stuff while there is snow on the ground.

BlueBee is correct - plastic sheeting doesn't offer much insulation value.  It stops the wind and rain.  As soon as the sun goes behind clouds, you can feel the temperature drop inside a hoop greenhouse.  You need some kind of thermal mass to hold the heat ideally.

Grandma used to start her plants in a 'hot box'.  It was a 3 foot deep pit, with a plastic sheeting lid over it.  Grandma would put fresh raw horse manure on the bottom of the pit about a foot deep.  As the manure composted, it would put off heat.

Being in Georgia, you might be able to get away with putting several 55 gallon drums of water in the greenhouse.  They would collect heat during the day, and the thermal mass of the water would help moderate the temperature at night.

Offline showme714

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Re: Anyone gardening in a hoop house?
« Reply #7 on: March 09, 2011, 12:36:29 pm »
I have a 12X30 hoop greenhouse.  I found that cooling it was more of a concern than heating it.  They get really hot if you get much sun.

You only really need to worry about heating it to keep it above freezing.  (Or to get seeds to germinate, but you can germinate them in your house and move them to the hoop house after they are seedlings if necessary.)  As long as your temps are above freezing, I wouldn't worry about heating it.

The Amish greenhouses have already started plants in their greenhouses.  Most of them have large woodburning stoves to heat their greenhouses, but they will be starting stuff while there is snow on the ground.

BlueBee is correct - plastic sheeting doesn't offer much insulation value.  It stops the wind and rain.  As soon as the sun goes behind clouds, you can feel the temperature drop inside a hoop greenhouse.  You need some kind of thermal mass to hold the heat ideally.

Grandma used to start her plants in a 'hot box'.  It was a 3 foot deep pit, with a plastic sheeting lid over it.  Grandma would put fresh raw horse manure on the bottom of the pit about a foot deep.  As the manure composted, it would put off heat.

Being in Georgia, you might be able to get away with putting several 55 gallon drums of water in the greenhouse.  They would collect heat during the day, and the thermal mass of the water would help moderate the temperature at night.

Yes, I wasn't dismissing the thermal mass aspect of it. I have also been told that the more plants/pots you have in there adds to the thermal mass.

I agree with you on the cooling being a problem. My hoop house is situated perfectly to get sun from early morning on it's south end to high sun across it's length all day. It will have sides that roll up 3 feet and I have double doors that can open up on each end. I am using white UV 6 mil plastic. I am going to dig a trench from the outlet on the back porch (approx. 20 ft.) to the hoop house and drop a heavy duty extension cord in it for power to the hoop house and add an exhaust fan. I hope this will be enough. What do you think?

Offline Countryboy

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Re: Anyone gardening in a hoop house?
« Reply #8 on: March 10, 2011, 12:14:40 am »
I find that early morning sun is fine.  It's that direct sun during the main part of the day that is the scorcher.

Rolling up the sides and opening up the ends will do wonders for helping you cool it down.  This will remove the bulk of the heat in the greenhouse.

If it was only 20 feet, I'd run the extension cord over the ground until you were certain the exhaust fan would work.  I'd also recommend running the cord through a piece of garden hose to protect the cord underground.

You may also want to look at a shade canopy to block some of the sunlight coming into the greenhouse.

Offline showme714

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Re: Anyone gardening in a hoop house?
« Reply #9 on: March 10, 2011, 12:43:04 am »
I find that early morning sun is fine.  It's that direct sun during the main part of the day that is the scorcher.

Rolling up the sides and opening up the ends will do wonders for helping you cool it down.  This will remove the bulk of the heat in the greenhouse.

If it was only 20 feet, I'd run the extension cord over the ground until you were certain the exhaust fan would work.  I'd also recommend running the cord through a piece of garden hose to protect the cord underground.

You may also want to look at a shade canopy to block some of the sunlight coming into the greenhouse.

Yes, I agree on the shade cloth. It is on my list of things to buy before the weather heats up too bad. I was thinking of putting the extension cord in PVC pipe and I wanted to have power in the hoop house any way just for GP.

Offline kingfisherfd2

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Re: Anyone gardening in a hoop house?
« Reply #10 on: July 04, 2011, 11:50:10 am »
Glad to see that there a some folks here that have experience with hoop houses.  I have 3 raised beds that I am thinking about putting a hoop house over to grow root and leafy greens.  For the most part in the piedmont of NC we have pretty mild winters.  Fresh veggies all winter would be a great benefit. 
Are you building them with PVC?  If so what size did you us for your hoops. 

Heat can be achieve with a hot compost pile.  with results of having a good source of compost in the spring.