Suggestions for a Greenhouse newbie

[3rdMaestro]

Hello all,
I'm considering constructing a small greenhouse in my backyard to move my collection into, a 6x6 or smaller. I plan to fill it more or less with tolumnia, and the stray phals that people keep gifting me. Since I'm new to this and still in design stage, I was looking for suggestions.
1. Tolumnia love air movement. I guess that means I need fans? Will any plain old fan do?
2. How does one control the amount of light? The place I was considering putting it has a shadow from the house begin to creep over the area after midday.
3. I'm not worried about the cold. I'm worried about the ridiculous summer heat. What can be done to fight the heat?
4.... Am I missing anything else?

[Ray]

First, you have to understand that you're battling conflicting parameters.

Tolumnias will prefer very bright conditions, while the Phalaenopsis prefer deep shade. Tolumnias high, phals low in the structure might help. Both like warmth, so you're good to go there. Tolumnias want frequent watering and fast drying, while phals prefer constant, moderate moisture.

Yes, any fan can work, but you're looking for tumbling breezes, not wind. Plus, you need to consider how well a fan will survive the environment.

Rather than relying on the house to provide shade, consider Aluminet shade cloth. It will control the light level and help with cooling - not that it would be enough - you must consider ventilation and possibly cooling, as well. A swamp cooler is worth thinking about.

A small structure, having a large surface to volume ratio, will be thermally unstable, so sun will cause rapid heating and shade, rapid cooling. That means you must focus on positive environmental control, as relying on passive means, house shade, for example, just isn't going to cut it.

[3rdMaestro]

Thanks for the info.
It sounds like it may be easier to keep my phals inside. Regarding the swamp cooler effect, I feel like I've heard people can accomplish that by watering some rubber mats on the floor and letting the fans blow across it, is that correct? Or does it need to be more "refrigerated" than that?
Regarding the shadow, I was worried the shade may create a problem where the orchids dont get enough light. Again, is that something to worry about, or am I overthinking this?

[Ray]

Evaporative cooling relies on a lot of evaporation taking the heat out of the air. I seriously doubt that passive evaporation from rubber mats would be sufficient.

Neither of the Orchid you mentioned can handle full sun. The idea is to have a shade cloth that reduces the sons intensity to the maximum level the plants can handle. That way you can leave the greenhouse in full sun all day without burning

[katrina]

Memphis tends to be pretty muggy in the summer, right? If so, a swamp cooler won't be all that effective. They work much better at cooling in lower humidity climates.

[3rdMaestro]

Yes, fairly high humidity compared. Is there something else that can be used? A window AC unit? Seems excessive, but hey....

[Ray]

Certainly AC will work, but it wil remove humidity. Katrina is right about the negative impact of high humidity, but don't write it off, as I've seen it work inside of a humid greenhouse in Houston.