How can I reduce heat inside greenhouse.
 

I do not have electricity (except 12V. solar) in the greenhouse. Standard temps from late May thru Sept is mid 90s here in North Florida. Greenhouse goes over 100 most of the afternoon)

I'm considering running misters on a timer (a 12V solution); Getting a couple of 12V fans from the junkyard (another 12 V that would require another battery/solar panel, etc). or getting a couple of "wind turbines and cutting holes in the plastic to let the heat out.

Do any of you guys or girls have experiences with these methods, or perhaps have a better solution? I'm all ears...


48T&C

Vent/open the bottom and vent/open the tops all the way down.
No I dont have a green house myself but it is the only way you will be able to dump the hot air out without power.

Worth.

Spray the white stuff on the plastic to cut the heat load.
I think its a clay.
Open it as much as possible. Cut it if you have to in a way thats patchable.

Both ends of the greenhouse are open, and the side plastic is rolled up for the summertime Just the top is covered in plastic, but its still VERY hot in there. My tomato production is way down. Flowering, but not producing little toms.

Thanks,
49T&C

Shade cloth.

What style of house?

What's the spacing on supports? Could you possibly stretch a piece of plywood across somewhat close to the top to mount the turbine type exhaust fan?

Increasing the humidity with the misters will probably make things worse...clumping of what little pollen the heat hasn't fry and increase the chances of fungus problems.

Ok only other thing I can find is this:
[url]http://www.greenhousemegastore.com/product/60-percent-aluminet-shade-curtain/shade-cloth_1[/url]

Pricey though....

I'd be very tempted to go with this...

[url]https://www.lowes.com/pd/Phifer-18X14-Pool-Patio-Screen-Wire/3034437[/url]

It will cut down quite a bit of sun. No, it's not quite as sturdy, but it will work (there is 'denser' stuff, too...so check the various offerings).

The house is 12 wide X 40 long X 8 ft tall hoop house, with 16 ft cattle panels making the hoop. The shade cloth is laid over the panels and plastic over the shade cloth. I have a steel pipe running down the middle at the peak which supports the tomatoes (on string). It has withstood a couple of very strong topical storms already, but there is no other bracing in the house.

49T&C

I used to throw mud on mine, before I finally bought some shade cloth.

Short of cutting holes in it, it sounds like fans must be the answer... you already have vented the sides and are using shade cloth, but the top is still trapping heat. The ends should be vented right to the top, and install your fan up there to blow fresh air through the top so heat isn't trapped.

Being in Florida, a solar powered fan would be the obvious solution to no electric on site.:yes::)

hmmmm..... if your outside temp is 90 and your gh only gets to a hundy, that's not too shabby. my gh is storage during may-October, as it can get 180 up in there on a 90 degree day - and that is with cross ventilation (door wide open & 2'x2' window open).

I have a fan and 120v, but pffffffftttt doesn't seem to help much. shade cloth does help - some - but probably need something from nasa if gets west sun. NoFlo can be brutal despite the "north" being in the name & sticky too.

a pic would be helpful, but have to ask why you are in the gh anyways, unless you plan on running some ac up in there.

[url]https://www.youtube.com/watch?v=QRgFp7thJMQ[/url]

At 4:37 is a mechanical vent. Need to be set into a frame though.

50% shade cloth is what all the growers here use.

[url]https://www.amazon.com/EasyShade-Black-Shade-Cloth-Resistant/dp/B008EPDIY8/ref=sr_1_2?ie=UTF8&qid=1517023278&sr=8-2&keywords=50+shade+cloth+for+plants[/url]

I only needed it for 1 side so for 20 bucks I dropped my temps inside 20 degrees

My stuff is the "aluminet," 45%. It looks like a silver foil mesh.

I use aluminet. too. it really does work better. we wiggle wire it right to the high tunnel. sell your tomatoes to pay for the stuff if it is too costly to pay for out of pocket. if you go more than 50% shade you will get NO tomatoes. they won't blossom. the screening from lowes... does it tell what the percentage is? if not I wouldn't take my chances on trying it.

Aluminet is def better, I just couldn't pull the trigger last year. This year I likely will.

@BigVanVader--

is the 50% shade cloth covering the S side??? I don't see any trees or bulldings to block sunlight on the far side so me thinks perhaps your GH is like my house where I receive MORE sunlight (reflected) into my house on the N side than the S that is crowded with oaks/maples/beech/etc that block most of the sunlight May to October.

It is facing west, so sun is shining on that side from about 10 am till dark. Sun rises right behind my GH so only a couple of hours shine on the east side.

Gotcha. Is it a regional thing how a GH is oriented?? Somehow I thought all GH ran E-W....

Idk, I just put mine in the best spot on my property for all day sun. I could orient one perpendicular to the south and make it work, bur it's not ideal.

Im sure terrain, slope and spacing plays a role.

[QUOTE=BigVanVader;680064]Aluminet is def better, I just couldn't pull the trigger last year. This year I likely will.[/QUOTE]

the rats used my aluminet to make nests or something - ate it up. careful w/ winter storage. they didn't mess with my shadecloth stash, I don't know why they went for the aluminet.......

I realize this is an older thread... has anyone tried or considered a "Swamp Cooler"?

Something I struggle with myself is heat build up. I need to purchase some shade cloth. Or do something.

[QUOTE=FourOaks;681369]I realize this is an older thread... has anyone tried or considered a "Swamp Cooler"?

Something I struggle with myself is heat build up. I need to purchase some shade cloth. Or do something.[/QUOTE]

Swamp coolers / evaporative coolers work well for arid climates where the air isn't saturated with moisture / high humidity.

In the summer time here when the humidity is really low I can spray the concrete drive down with a big fan on it.
I get really cold air coming off the fan.
Another place I like to do it is my golden goddess bamboo grove.
Feels like a refrigerator door opened.

Worth

[QUOTE=Worth1;681418]Swamp coolers / evaporative coolers work well for arid climates where the air isn't saturated with moisture / high humidity.

In the summer time here when the humidity is really low I can spray the concrete drive down with a big fan on it.
I get really cold air coming off the fan.
Another place I like to do it is my golden goddess bamboo grove.
Feels like a refrigerator door opened.

Worth[/QUOTE]

I understand what your saying, and honestly always thought there was no hope for humid areas.

I forgot to post this UMASS study:

[url]https://ag.umass.edu/greenhouse-floriculture/fact-sheets/fan-pad-evaporative-cooling-systems[/url]

They indicate, that even upwards of 70% humidity, you could have around 10 degrees of cooling.

One thing I have learned in a few years of Greenhouse/High Tunnel growing, ANY cooling is still cooling.... Combined with a shade cloth, and this could be interesting.

60% humidity and below will dry peppers.
Where I live it can get up close to 100% sometimes.
Depending on which way the wind is coming from.
Worth