If it is uncomfortable for you, it is too hot.

Not sure about the ants.

My ants also packed up and left once the GH hit 110 F every afternoon.

>> GH hit 110 F every afternoon

Yikes! I thought my GH was bad. :)
Its peaking at 105F outside but the GH was still relatively cool, around 95F. Its still too hot for my liking though.

How are you cooling your GH? If I turn on the fans it helps but since all the plants are outside for the summer we don't bother.

For my size GH and in our area, it is nearly impossible to fight the heat in a closed GH unless I flop in a swamp cooler or airconditioner in there.
So for summer, my GH is set up as a shadehouse. All doors, windows and vents are open to try to equalize the outside and inside temps. I have shadecloth on the entire roof and south facing surfaces.
I have a circulation fan inside to help out, and misters that come on for 3 minutes every hour for some extra cooling.

My previous orchids were ok with the summers here under a simple shadehouse - its the frost that killed them.
So as long as I can keep the GH's inside temps equalized with outside temperature (or possibly lower) they should be good in summer.
So far, the GH has been a bit cooler than the outside temps.
The reason I built the GH is to shelter the orchids from the chilly winters. We dont get any real snow but the wind gets frosty enough to turn orchids to mush. I even lost a lot of cymbidiums last year. They usually just shrug off our winters.

Wow!!
That is hot lol My carpenter ants didn't move when the wife set the kitchen afire lol
In my location I don't need a thermometer if it's not late Jan it's too hot. Though we very seldom get above 95 the nights can stay in the 80's but am fortuneate in that the humidity will raise to suffocating when that happens.
The winters are just cold enough to cause stress ,never fatal just frustrating.
I've redone my grow area using a wide open approach and heated water. Wasn't cold enough last winter for a test but I'm sure WAY ahead for the summer.
gary

Mine stayed and I think they brought the relatives also. I am going to enforce immigration laws soon. They are crossing the board to fast....LOL

My greenhouse hit 120 today. I bought another fan that goes on the floor and aims at the roof. This, with the fans for HAF will I hope, make it cool enough for us to start building the shelves.

I don't know how hot my greenhouse is. I have not been in it for weeks!

It may be cloudy and raining tomorrow, if it is I will spend some time in it.

:)

"I bought another fan that goes on the floor and aims at the roof"

Okay. That goes with the fact that hot air rises, but has anyone else thought about the way GH's are designed today, that in many ways seem to be simply because that's the way they have been for the past 100 years?

Yes, polycarb has pretty much replaced glass, but the basic design hasn't really changed at all.

Roof vents are fine for passive warm air release, but we all know that isn't enough when it gets really hot, but those passive roof vents go back to the time before there was even electrical power, let alone electric fans.

So a Question:

Would losing the small amount of sq. footage taken up by a really powerful roof vent be that great a loss of light in a GH?

If a GH were designed with a cupula in the roof, wide enough to accomodate a large roof vent, it would not affect the headroom in even a low ceiling GH, would just about pull the false teeth right out of Grandpa's mouth, and the cost would be neglible in relation to that of the GH and accessories.

Just a thought, for those fortunate to be able to design and build their own GH, using materials and equipment unheard of just a few generations back.

Greenhouser, do you plan to keep the GH closed during the summer? If so, do you have an exhaust fan?

I'm not really impressed with passive cooling capacities of the GH kits available today. For my Rion 8x16, even 3 roof vents and 3 windows that came with it are not sufficient.

For effective passive cooling, I probably need at least 5 roof vents on either side. Or like birdwidow said, a real large roof vent for unhindered convection.

For now, I just leave all portals open and let mother nature do the heavy lifting when it comes to air transfer. I may tweak it later on once I learn more about this GH and how it interacts with my micro climate.

About a month ago my greenhouse had reached 110 degrees and that was with a swamp cooler and three fans running 24/7. The cooler was running from a well on my parents farm and is their only source of water. I shut the cooler down, brought the orchids back to my house and office and called it a day. We are in a severe draught here in Tennessee and I was not going to run the risk of being the reason my parents don't have water. We have only had about 2/10 inches of rain in over 45 days and are at least 17 inches behind for the year. I would say these factors were a good reason to determine if my greenhouse was too hot. Pray for rain.
Cindy

I wish I could afford something on the roof like a cupola with a fan. But then even if I could, I don't think that's possible on a Rion or HF. :(

Wetfeet:

I think I used the wrong term to convey my meaning. I was referring to one of the thermostatically controlled, powered roof fans most commonly used to cool attics: the ones equipped with domes, to keep out rain.

They are not very expensive, easy to install, and quite effective.

* Posted by wetfeet101b z9 So Cal (My Page) on
Mon, Jun 18, 07 at 11:53

Greenhouser, do you plan to keep the GH closed during the summer? If so, do you have an exhaust fan?

ME: It's not closed. All 4 roof vents are open as are both doors. No exhaust fan. We do have 2 hanging fans for HAF and the new fan on the floor pointing up twords the roof to help move that hot air out.

I'm not really impressed with passive cooling capacities of the GH kits available today. For my Rion 8x16, even 3 roof vents and 3 windows that came with it are not sufficient.

ME: They sent 4 roof vents with auto-openers but no side windows. It hits 120 F when the sun hits it.

For effective passive cooling, I probably need at least 5 roof vents on either side. Or like birdwidow said, a real large roof vent for unhindered convection.

ME: These GHs would need an almost open top (all vents) for passive cooling to work. That could be very expensive. My husband finished the electic work in the Rion today with the 3 fans going. They did bring it down to the high 90s. Of course the fans do nothing for the humidity. :(

For now, I just leave all portals open and let mother nature do the heavy lifting when it comes to air transfer. I may tweak it later on once I learn more about this GH and how it interacts with my micro climate.

ME: Which GH do you have?
I'm not too concerned about the excessive heat unless I have to work in the GH. I then wait until 3 PM when the sun goes behind some huge trees. The temps drop to outside temps once the sun is blocked. All my plants are outside for the summer so they're not a concern.

We're in a severe drought here in the Nashville area as well. It's terrible. We fear fires now. The woods are only 20' behind our house and they were set afire about 20 years ago. I had to evacuate and only by a stroke of luck did the fire turn at the last minute with the help of firemen. What a nightmare that was.

Oh... I missed it the first time and went back and read your post again. I see you also have a Rion 8.5 X 16.5. Windows? What kind of "windows" do you mean? Our Rion came with 4 roof vents and double doors.

birdwidow,
I did not read your post properly. I understand what you mean now :). We installed one of those rotating roof exhaust fans on a friend's garage and it was working wonders.
If I remember correctly though, the entire kit weights quite a bit. I'm not sure if there is something that is small enough that can be supported by the Rion GH, and still be effective.

greenhouser,
The Rion GH kit that I got (Rion 8.5x16.5 Prestige Kit) came with 3 roof vents, and 3 louvered windows. All came with auto openers.

Here is a picture of the back end of the GH, showing one of the louvered windows:
{{gwi:298905}}

I placed one window on each side and the back side of the GH. I then placed two roof vents on one side, and the third roof vent on the other side.

Those two small box fans on the roof vents were earlier attempts to speed up the exhaust of hot air but proved to be ineffective. Those two fans are now used for HAF - one hung from the top facing one way, and another set on the floor facing the opposite direction.

The picture is a bit outdated, as I have rearranged the entire GH interior for more efficient air flow. I will try to take a more updated picture when I get a chance.

Wetfeet:

Rotating exhaust fans? I presume you mean the powered type, with the mushroom caps, as opposed to the old hot air generated turbines?

If the electric, mushroom capped; then yes, that was what I was referring to. But please note that I also suggested it as a thought for anyone constructing their own GH.

Given new, wood framed construction, including the frame for a cupula in the working plans would be easy. It could just as easily be framed to fit 4 self opening vent windows in the cupula side walls, with the powered vent on top.

We have 2 powered roof vent/fans on the roof of our house, and between them, they keep the attic at the 82. deg. the thermostats are set. It helps cut the AC bill at lot, and while crawling around up there at high noon in summer is no great joy, it's bearable.

So: if only 2, 24 inch roof fans can keep 2600 sq. ft of attic under a black asphalt shingled roof at 82 deg., while it's in the high 90's: what effect would one have atop a 200 sq, ft. GH. Few home GH's are larger than that and most are smaller.

But those fan assemblies are not heavy. We just bought a new 24" for the duck house, because it was cheaper to replace it than fix an old, burnt out motor and I had no problem picking it up off the shelf and into the shopping basket.

It cost all of $39.99 at Menards. I doubt it would be more at any other home center. Oh, sorry: that was for the fan/motor/thermostat assembly only, which is all we needed. The caps are sold seperately, but are still cheap.

But I can see where it would be a near impossible challenge to retrofit a Rion for one.

However, on an aluminum framed GH, with some polycarb cutting and some extra aluminum angle to create headers to support the fan, it just might be doable, and one 24 inch powered roof vent is probably worth 6 passive ones of the same size.

I was referring to one of these. :)
Its just driven by wind and hot air.

Here is a link that might be useful: {{gwi:298904}}

Ah: the old squealers. We have some on the roof of a big Morton hay shed. They help, but don't really cool: just release enough hot air to keep tons of stacked, baled hay from getting so hot they combust.

The turbines are passive, so while it's true they don't need wiring; are better than simple screen vents and will make a difference in an attic, they really aren't effective at actually pulling air up from the floor of a GH with enough force to make any real difference in interior temps.

Better than nothing I suppose, but they simply can't compete with a powered fan, even if that fan is just a lightweight box fan, suspended directly under a GH roof vent.

Check out the lightweight box fans at any home center. I can't believe that even a Rion wouldn't support the weight a several of them.

We got the kit that came with the roof vent openers and plastic foundation thing. I believe my husband paid $2,600 for for the kit. That included shipping. I saw no option for vents such as you have, or anything else. We will have to buy them separately as cash allows.

Yes, please take some new pics. :-))) I'd love to see how others have their HGs set up, especially their Rion's laid out - what extras they have etc. As soon as we're done with the shelves etc. I'll post a few of our Rion here.

With the turbine - how would you keep a GH heated in winter? The heat would quickly escape unless it was sealed off somehow or removed.

>>With the turbine - how would you keep a GH heated in winter? The heat would quickly escape unless it was sealed off somehow or removed.

It would probably need some sort of a trap door underneath that can be sealed in winter.

Here are some updated pics of my GH:

This is the west facing side. Every surface, except the window area is covered in 50% shade cloth.
The two western roof vents are also visible from this angle.
{{gwi:298906}}

Full shot of the interior, just prior to rearranging some plants. I still have LOTS of free bench space for new plants! hehehe.
The south window is also visible from this view.
{{gwi:298907}}

The cattleya section (One stray dendrobium anosmum is visible there also)
{{gwi:298908}}

Cattleya backbulbs in rehab:
{{gwi:175539}}

Cymbidium Alley:
{{gwi:298909}}

The vanda section is new. This is the first time I am growing vandas. There is a dedicated mister nozzle at the roof, pointed down at the vandas and other mounties.
{{gwi:298911}}

My potting bench. LOL.
{{gwi:298913}}

Assorted fruit seedlings section:
{{gwi:298915}}

Let me know what you think. I would appreciate comments and recommendations.

Wow... I am so impressed!!! :-)) I love your set-up. Your pics have given us some ideas. Do you find a problem with mold growing in/on the shredded bark on the floor? Do your orchids get enough light through the shade cloth?

Your orchids are so healthy looking. I recently bought 5 small catts, an ocidium and some dendrobiums in the past 6 months. I lost almost an entire collection to a bad storm over a year ago. They were hanging in a tree that came down and crushed them while we were out of town. I'm slowly buildig back up. I'm not sure if I'll keep my orchids in the sun room this winter or in the Rion.

We're going to start on the benches next week. Then I'll take some pictures. :-)

Please keep the pics coming people!

Lynn.....

I have not noticed any mold or fermentation happening on the bark flooring. Since I regularly spray the GH interior with Physan 20 to prevent mold and mildew anyway, I guess that helps with the floor as well.
The bark is only temporary until I can save up enough cash for lava rocks or some other inert but moisture retaining gravel for the flooring.

With the current shade cloth setup, the plants are still getting 5000-5500fc of light from all directions (according to my light meter).
The catts and cymbidiums love it. Even the bottom shelves are getting somewhere between 3000-4000fc.

This is what my light meter registers:
Direct sun: 6800-7200fc
1 layer of shade cloth + glazing: 5000-5500fc
2 layers of shade cloth + glazing: 3000-4000fc

OK thanks for the info in Physan20. :)

We have crusher run limestone gravel in the Rion. I had to rake out the larger chunks as they were the pits even with shoes on. I used them in the driveway. I wont know how much humidity it'll hold until this winter. The HFGH was at 20% all last winter but the plants thrived anyway. I'd wet down the brown gravel but the humidity would drop again in hours. I have an old water breaker humidifier I plan to use in the Rion if humidity is a problem.

I don't have a shade cloth yet. I hope to have one by next summer. You're GH is still getting a lot of light. The pics are deceiving. It looked quite shady.

>> You're GH is still getting a lot of light. The pics are deceiving. It looked quite shady.

It is probably because I'm just using a simple point & shoot digital camera. The light levels outside is so much brighter than in the GH and the camera could not properly get a fix on the proper light.

Yes it does look shady, but the orchid leaves and a couple of different LIM's indicate otherwise.

I tried to put my lone Phal in there for a couple of weeks. The poor thing turned so purple it looked like it was ready to sing a Barney song.

I will try to take some better pictures with a Cannon film camera - but my wife usually does not appreciate me using up a dozen rolls of film in a 30 minute trip to the GH lol.

Phals don't care for sunlight at all. Mine were getting too light green. They're now behind the dendrobiums on the porch so get broken or dappled shade. They're back to a nice green again.

I can use up quite a bit of film myself amid the plants and gardens. I wish all my friends and relatives back east had computers. Sending digital pics is quite a bit faster, easier and cheaper.

Well what do you know... As soon as I got the GH daytime temperatures to stay below 100F, the stupid ants move back in.
GRRRR!

Now I need to figure out a plant-friendly way to evict the ants again.

I hate ants. Ants are pest farmers.

If you guys want a powerful fan, get a fan for car radiator.

Very powerful, except you'll need to hook it up to 12V DC.

Can be variable speed.

dcarch