Semi-Hydro & Heat

[Shawna]

Thanks to both of you.

[Rivka]

i know this is older but i would rather less, more useful, threads on a given topic then too many scattered ones.

what do you guys think of using these floor mats to do large shelf bottom heat? Indus-Tool FWB 16-by-36-Inch Foot-Warmer Mat vs the product that is designed for it like Hydrofarm Seedling Heat Mat 48x20

both seem waterproof, 90-120watts vs 107watts respectively so the specs seem similar, though since the are described for such different uses it is hard to tell how similar the heat they put out are, my gut says the floor one is probably warmer. i have a windowsill plant one now and although i know it works it is very subtle to the touch, cant see it working thru shoes under a desk for instance. the floor matt one seems like it would be sturdier, but in my particular case the plant one does fill my shelve a bit more perfectly. i have most my plants on 48x18 metro racks, although i have been working on adding some drain trays to the shelves that would also make them wider than the 18 by a bit.
my plants are about to go from their summer home on a shaded deck to my first small 4x10ft lean too greenhouse that is adjacent to a sliding glass door and therefor my home. Im looking into various ways to heat it the best and to have some redundancy in the system.
heat mats seem to have a number of benefits in the whole plan.


lastly, Ray, do you get these larger 48x24 mats? Can you beat this price is i ordered maybe 4 of them?

[cbuchman]

I've owned a foot warmer mat and it gets quite warm; they get warm enough to make your feet sweat. I would think this would be too much warmth and would fry your orchids.

[Rivka]

good info, what about if this was outdoors? i an leaning to agreeing with you, but also so worried about wintering my orchids in a greenhouse

[cbuchman]

If you decide to use, even outdoors, I would think that you will need an air space between the pots and the mat. I've never done this I am just trying to apply my limited experience. I'm use the seed warming mats in my greenhouse.

[Rivka]

do you feel like they do a good job warming your pots?

[cbuchman]

The seedling mats are warm to the touch, but I'm not sure that they raise the temp the advertised 10 degrees (so far my measurements do not indicate this). So I put the mats under mini-greenhouses which does seem to improve humidity, but I need to be careful that there isn't too much moisture and not enough air movement. It seems to be a balancing act and I don't think I have it right yet.

[Rivka]

im guessing for the full effect they would have to be in nearly direct contact with the posts themselves. i have also heard the recommendation to lay something insulating or reflecting under them to push the heat up. I'm thinking a thin layer of Reflectix if it does not make ti wobble too much, but maybe even just heavy duty tinfoil

[cbuchman]

Hmmm - I might try the heavy duty aluminum foil idea. I have some in the house and it wouldn't be difficult to try

[Rivka]

it would be very interesting to measure the temp of the reservoir water before and after adding the aluminum foil and without the heat mat at all, i bet you get a decent difference.