Soil heat is used only for germination. Once the seeds germinate the warmed soil can quickly cook the tiny seedlings, especially roots. For growing-on cooler air temperatures are recommended. 60-65 degrees is recommended. Dave

My point of view is that I grow a lot of weird varieties from time to time. A LOT of times certain seeds NEED a constant temp. to germinate. They just won't germinate at 70-75 degrees or whatever. They NEED 77-79 degrees ONLY to sprout. Too hot or cold 1 in 30 seeds MIGHT sprout. At 77-79 degrees I get 1 in 5 to sprout if not more. It depends on your grow. ALSO I had problems with learning how to properly use heat mats. YOU MUST insulate the heat mat from what it is placed on (without the thermostat). OR the shelf/whatever either gets too hot/obsorbs all the heat and your soil is cold... Without the thermostat you are relying on the mat itself to regulate it's temp. Sitting on a warm shelf that it heated up doesn't let the stuff on top get warm enough. I find a LOT of basement growers complining about cold seed trays,without thermostats. regulating the heat on un insulated mats adds too many variables to get the heat wher it is needed. Mat runs on a wire rack acording to room temp. You cook your seed trays. On a heat conductive surface the trays get too cold.The mat feels a warm shelf it's set on and shuts off.Cold seed trays result. Once they put scraps of the 1 inch packing styrofaom sheets under the mats their problem was solved. Just adding a sheet of packing styrofoam CAN make a BIG difference. Just something to think about,depending on your grow. The bigger it is,the more important it is to get even sprouting and growth. Especially when you have a winter/short season. for a single 72 cell starter or several 12 cell startes. I find the smaller ones are a LOT easier to get the bigger/early stuff out of without messing up the cells around the sprout I want to pot up... http://s403.photobucket.com/user/smoemaster_2007/media/IM004351.jpg.html?sort=2&o=1058 Covered mini greenhouses add up to the same amount of cells and take up the same space. They are just easier to work with. http://s403.photobucket.com/user/smoemaster_2007/media/IM004352.jpg.html?sort=2&o=1059

Thanks Al, I started to look up rooting cuttings with a mat and there's even more info on that than for seed starting.... it's going to take me a while to get through it all! Thanks for the lead

Rina - these plants and some other tropical succulents are very temperature sensitive. Although my apartment probably won't get colder than 65 degrees F, I'm worried that the draft from the windows will make it colder, especially in like January or February when it get bitterly cold here. Minty - the indoor temps would be at least 65+, but for a lot of Somalian and Soqotran succulents, that is literally the lowest advisable temperature I have seen on the internet. I would probably want to put all my Dorstenias (gigas, lavrani, foetida, barnimiana, cuspidata, and zanzibarica), all my Pseudolithos (2xcubiformis, dodsoniana, miguirtinus), some of my other Asclepiads (Whitesloanea crassa, Stapelianthus madagascariensis and decaryi, Echidnopsis specksii) and a few Malagasy Euphorbs (tulearensis, bongolavensis, cylindrifolia var. tubifera, maybe a few more small species) on the heat mats. cactus - yeah, these species are kind of tricky that way! their winter is more of a dry mild warm season that a cold one. I think you're right, I wouldn't want to give like 80 degree bottom heat during winter, but I've been reading online and some people say that keeping their root zones around at least 70 degrees can help these plants survive the winter more easily dog - thanks for the info!! your gigas is beautiful :-) i see you have some D. lavranis heating up as well! if you don't mind me asking, does running the heat mat during winter raise your electric bill a lot? you can PM me about it if you like, or you don't have to answer if that's too personal!