I was wondering if the roof vents would make it cooler. I have my exhaust fan set at 90 and it keeps coming on. I was getting ready to experiment with the roof vents and open them to see if it would help. I love your door. When mine are no longer functional, I want to do something similar to that.

I have my exhaust fan set at 90 also and it comes on everyday. I'm trying to get my misters to work but haven't had much luck. May have to replace the system.

Why don't you put your plants outside for the summer? All my plants spend the summer outdoors and thrive. Some are in the shade under some trees or on my porch, others are in the sun. They'll go back in the GHs shortly before our first frost is expected.

inside the greenhouse is now the same temp as the outside. Problem being that today is supposed to be 104F, yesterday was 102F.

Moving banana trees and an 8' cactus isn't happening!

Hi Troy,

I looove your gh. I believe sherry Mudhouse made screens for her gh to keep temps down. I hope I am not mistaken. That should also help with keeping the temps down.

I had to take all my plants out it was too hot. I need to make some adjustments also. Barb

Troy, if you're considering screens, here's a link to my thread about making screens using Aluminet shadecloth as the screen fabric (trying to kill two birds with one stone.) Since this thread, I've learned I can put the screens back in place on the outside of the poly panels in the winter time, too. I like them a lot.
Aluminet shade cloth screen panels

We've had a few temps over 100° here so far also. Lately my GH gets up to 104°-106° during the hottest part of the late afternoon, with exhaust fan, screens, shadecloth. That sounds scary, but it doesn't hurt my plants. If I can live with that (and I think I can) then I can get by without looking into some kind of evaporative cooler, which I'm hoping to avoid.

The Aluminet shown in the thread above is opnly 40%, a really big goof on my part. I have more 50% Aluminet on order to add a secondary drape to the outside of the roof, and to my west wall, to increase my shade density in summer; that will give me the equivalent of 70% density on those surfaces. Still learning here as I get through my first summer...an unusually hot and dry year so far, a good test!
Sheri

I got my misters going, they had been clogged and that made a huge difference. I run them during the peak hours.

My shade cloth is 60%. The way I figure it, the fans going and at least the air is moving through the GH. It's dead still outside, not a breath of wind.

Next year I hope to add a deck and arbor to the west side of the GH.

I have been experimenting. So far the coolest has been using 50% shade cloth over everything but the North wall , exhaust fan set at 90, HA fan, roof vents open and door open, misters coming on every 2 hours for 5 minutes. I'll probably adjust as the summer gets hotter. I have orchids in there and I don't think they like it much over 90 or so.

Are you growing shade plants? 70% blockage is quite a lot for sun and semi-sun lovers I would think.

Are you growing shade plants? 70% blockage is quite a lot for sun and semi-sun lovers I would think.

Greenhouser, since I mentioned 70% above, I'm assuming you're asking me? No, definately no shade plants in my GH...only cacti and succulents, sun lovers. I did not think I'd need that level of shade either. However, in my location/altitude, the sun is apparently extremely intense (especially overhead and afternoon) in mid summer. I'm just going by what my plants tell me, and I'm finding I need to move more and more under the benches to avoid sunburn. No sunburn yet, but extreme coloration and lack of growth tells me many will grow better with a tad less light...just through this tough time of year. When I move them to lower light, they start growing better...but there is only so much room UNDER my benches!

Once we get through this tough summer period, I plan to remove the extra shadecloth layer, and fall back to a lower density again. My south wall is still only 40%, and my east wall has no shadecloth.

103° outside today...108° in the greenhouse...hottest so far this year. Once the extra shadecloth is in place, I think/hope that will drop by a few degrees.

Oh I see. My cacti and succulents spend the summer out on a large old picnic table. They get full sun for more than half of the day. But I'm in zone 6.

With a 50% shadecloth and 15% polycarb drop, I still get 7000 fc's in the greenhouse. More than enough sun for sun lovers and I have additional inside shade cloth for the low light plants on the west wall.

I'm having to rearrange some cattleyas because they were turning too yellow so they have to live in back of some of the more sun tolerant ones. The vandas happy though :>)

Brooke

The best thing I've found to keep temps down are the auto-openers for the roof vents and the misting system. Often shadecloth just isn't enough. For really hot days I have a large white tarp to use in an emergency for total shade. I only have a 6x8 but the mist system can pull the temps down 10+ degrees F in about 5 minutes... it's really fast.

Would somebody please post pictures of their misting system setups for us newbies. Definately a learning experience for us who have no clue. Thanks for the help. Barb

Barb, my misting system is super simple and inexpensive... here are some pics from when I first set it up. These are just basic drip system parts on 1/4" line. Took me about 15 minutes to put it all together, and I simply attached it to the shelf with zip ties.

This is the adjustable mister head (turn the knob for more or less mist)
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There are just 3 misting heads along this 8' shelf and it's adequate mist for both the shelf and the raised bed below.
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Haller Thanks so much for the pictures. I have a drip system I bought but did not understand how to do it. I know I can do it now. Thanks once again. Barb

Glad it was helpful, Barb... in my opinion, the hardest part about putting this stuff together is figuring out what parts to get! there are so many! Good luck!

I grow orchids in a makeshift gh, and control temps pretty well with an air chiller I added this spring. Its efficiency depends upon the ambient humidity, but allows me to grow intermediate orchids along the wall next to the intake. When humidity is near 20% I can reduce temps about 7-8F in that microclimate below outside ambient, such than when it is 90-92F outside I can have temps in the low 80s next to the intake. The rest of the gh temps are lower as well. When humidity is higher, the benefit is less. I have plans to make the chiller larger by two-thirds, as it is not quite large enough yet.

The chiller is an exterior structure, with both an intake and exhaust fan operating it. Inside are fogging heads, and chambers separated by plastic furnace filters. Initial cost was ~$75, and when I add on, maybe another $75 or so.

With orchids and other sensitive tropicals, using an interior misting system to lower temperatures is not always a good idea. (Unless it's time to water.) You could end up making plants wetter than they'd like, or have residual water overnight in crowns/leaf axils. Excessive water also invites things like botrytis, and shortens the longevity of blooms. Under-bench misting is good, but requires a separate system and valve/timer.

I also use some shade cloth, but in the interior depending upon the needs of various orchid types. So, my use of it is only to control light, not temperature.

-Bruce C.

This is the setup I have in my very hot Nevada desert greenhouse. The temperature inside usually says around 90 degrees during triple digit afternoons. I have a shade cloth, ventilation fan (set to 90) and misters. Also, I keep the window open on my storm door.

Here is a link that might be useful: My Setup

We get many many days of temps over 100 degrees here. I took out one door panel & replaced it with hardware cloth (the stiff wire mesh with 1/4" squares) then I take out 1 or 2 roof panels & put hardware cloth in them. This sets up a convection that takes the hot air up & out. The hardware cloth comes in 2' widths which is perfect. I also cover the top & afternoon sun side of the GH with shade cloth. If we get temps over 105 I will still get a few cooked tomatoes but only the ripe ones. The green ones don't cook as easy.

If you don't have climbing rodents like I do you could just use shade cloth in the openings.