Heat mat use and temp control, with S/H

[Dalton]

Hey all,

I've been reading through the S/H section again, getting some great advice. Something I plan to setup today is a heat mat. I have Sandlewood heatmat. I believe it's 10"x20" or something close to that. I have recently transferred (2) orchids to S/H as well as having a couple of new orchids that are still getting established and used to my growing environment.

To help them out, I want to use my heat mat, but I've never used it before. I do have a cheap seed starting tray and the heat mat is supposed to be 100% water proof. I'd bought a thermostat to control the temp on the heat mat. However, I don't quite know how I'd use it. With soil in the seed starting tray, you'd just stick the thermostat probe in the dirt and it would turn it on and off based on that temp reading.

How would you do that with S/H, or should you. If I can use the controller, do I just stick it in the top of the S/H pot or should I stick it in one of the drain holes, for a reading lower in the media. I also want to put a Podangis Dactyleras (probably butchered that name) on the heat mat as well. I plan to put a small container of water in amongst them as well. I figure it that at worst, it can't hurt anything and at best, the warm water will raise the humidity some in my room. I think ambient humidity away from the mass of plants is around 50% and it bounces up and down a little.

If I were to stick the probe in the top of the media, I worry that the small orchids in the tiny pots would over heat.