Hoop House

It might be better insulated than before, thereby holding night time temps!
Check again after a day of solar gain.

Yeah I would think it's the same as with a house when the windows are left open at night to get cooler air, then you close them in the morning to keep it cooler as it warms up outside (in the summer). Your greenhouse will still get cold at night, and until the sun can warm it up the interior can be cooler than outside.

Scott Foster wrote:

Mike Turner wrote:Built this cattle panel hoop house 2 years ago. 50 feet long by 10 feet wide with a  door at each end. Foundation of 2x6 boards staple rebared into the ground with the cattle panel stapled to the board.  I remove the greenhouse film in spring and replace with 30% shade cloth.  In the fall, the shade cloth comes off to be replaced with greenhouse film.  Growing figs, citrus, and vegetables inside.

Thanks, Mike.  Looks great!  Good idea with the shade cloth.  Love to see how you used the bicycle parts to do the roll-up.

Regards, Scott

No bicycle parts used on my hoop house.  The advantage to using shade cloth only in the summer rather than simply throwing shade cloth over the greenhouse film is that it stays cooler with just shade cloth since it gets better air ventilation.  It also allows rain to enter the hoop house so i dont need to water  as often through the heat of the summer.  Also since it is only exposed to the lower winter uv levels, I should get at least 9 years use from the 4 year guaranteed greenhouse film.

Scott Foster wrote:

Mike Turner wrote:Built this cattle panel hoop house 2 years ago. 50 feet long by 10 feet wide with a  door at each end. Foundation of 2x6 boards staple rebared into the ground with the cattle panel stapled to the board.  I remove the greenhouse film in spring and replace with 30% shade cloth.  In the fall, the shade cloth comes off to be replaced with greenhouse film.  Growing figs, citrus, and vegetables inside.

Thanks, Mike.  Looks great!  Good idea with the shade cloth.  Love to see how you used the bicycle parts to do the roll-up.

Regards, Scott

No bicycle parts used on my hoop house.  The advantage to using shade cloth only in the summer rather than simply throwing shade cloth over the greenhouse film is that it stays cooler with just shade cloth since it gets better air ventilation.  It also allows rain to enter the hoop house so i dont need to water  as often through the heat of the summer.  Also since it is only exposed to the lower winter uv levels, I should get at least 9 years use from the 4 year guaranteed greenhouse film.

Mystery of the hoop house temperatures solved.

Sometimes things are so simple you can't believe it. I had an old bulb thermometer in the hoop house. I bought another of the same brand to compare outside and inside temps. Same thermometer = fair comparison, right? Wrong! The older bulb thermometer had slipped in its housing giving a false reading. Doh!

Scott,

On the off chance you are still monitoring this here's an update on my hoophouse project.

I have completed adding a second layer of plastic on my cattle panel hoop house. Added a total of 190 gallons of water (milk jugs and 3 55 gal drums.) all painted black. Finished it off with pallet counters covered in terra-cotta tiles.

At the end of a miserable cold and rainy week here in the Pacific NW with an average outdoor temp of 45 degrees, the average interior temp was 51.8!
Even better, the interior temp At sunrise was always at least two or three degrees higher than outside.

Not sure how much of this improvement was due to the plastic and how much due to the added mass, but I think I can state pretty conclusively that double walled hoop houses do create a better growing environment in winter in the Maritime Northwest.

I've got 100 feet of rebar hoop houses, and the only thing I had to change was the rebar or metal needed to be inside of slightly larger PVC pipes because the metal gets too hot in the summer and breaks down plastic sheeting.   Then when I shelled out for greenhouse panels, I was able to put screws through wooden slats, then through the panels, into the gap between the PVC pipe and the rebar to attach just about anything.

The hoop shape is great in the wind.  The height is 7 feet so the heat stays down around the plants, less to heat than a high ceiling.

Lots of good ideas/photos here on the greenhouses.

Just wanted to add an idea for gentle floor heating.  For the cold climate folks/ compost acceleration.

To keep my masonry sand from freezing , so I can work in the winter, I lay out a 4x8 sheet of 1.5 inch rigid foam on which I lay a 4x8 sheet of reinforcement mesh(6 inch squares) . Onto the mesh I fasten an about 80 ft heat cable of the type used to keep rooves and eavestroughing ice free in winter.I lay it out with about 4 inches between the cable and strip tie it as required.THe whole sheet of mesh can then be moved around as required and you just plug it in. It draws about 400 watts but can be used at night only or only in the severe cold. Makes a huge difference. Depending on your power rate the cost is minimal. Here it runs about 6 cents /hour. This could be done with shorter cables or just around the perimeter etc etc.

The insulation prevents heatloss to the ground and really boosts it up. This is also a good way to give seedling a boost in the early spring, bottom heating.

This has worked so well for me over the year I thought I would share it as it can be a big help in the northern areas in a greenhouse floor or bed bottom.