ground yourself for fear of electrocution ...

try google for a bottom heat pads ... maybe amleo.com ...

others have used waterbed heating pads ... at least they are made for use with errant water ...

good luck... and be safe ... ken

NNNZZZZZZTTT NNNNNZZZZZT
LOL, I should have made it clear, that this is a closed system, and all my cuttings/seeds are in pots in containers. There is no way for the water to get on the blanket....maybe the slightest if I over mist, but prob not much of a chance. But it should work ....right?

I think the fire hazard is a much bigger concern. I know people do it but I think it's a shame to burn your house down due to improper use of a product. The same goes for the waterbed heater. Spending the money for the proper equipment has always made more sense to me.

Albert - thanks for the laugh!

Sue

More reasonable might be a heating pad, or a pet house heater. These are generally encased in rubber, and also will tolerate being covered closely. Covering an electric blanket with any sort of an insulation (such as a tray of plants) is a specified no-no. Despite this, if the whole blanket is covered so that the thermal cutouts are also insulated, it should keep you fron burning down the house.

Another, even better, option is a pipe heater tape. These can be had in long lengths, and can be zig-zagged to fit your space exactly.

George

I have been using heating pad for germination of seeds for quite some years.For safety you may use metalic stand beneath the pad.
Good luck.

No heated blanket, thank you.

Not sure if I can explain this setup, but I saw one in a mom and pop greenhouse that worked like a charm. "Pop" built a wooden box with a "bottom" midway of the height. In other words, if you turned it upside down it looked the same as right side up. She had damp sand in the top half and a heat source suspended underneath. It had a lid to hold the heat in until the seed started to germinate, then they were removed to a bench with plenty of light. A plastic cover with lights above it for propagation should work as well.

Heat source could be a light bulb or a very small heater (milk house heaters have thermostats) on low setting. Just have to play with it to get the temp right in the sand.

I must say that I would not risk doing any of these things in the house. Her's was in a greenhouse.

I have 2 2x4 foot light shelves with 2 double 40 watt shop lights over each. I have found I get awesome germination under them as long as I cover the pot tops with plexiglas covers. I remove them when the plants hit them.

I have even used this in my unheated garage which is under my house. I've done a great variety of plants this way with great success.

John

I use water bed heating mats under aquariums covered with glass and partly filled with sand and watered with a Vitamin B solution with great success. Of course, water never, ever touches the mats, I don't have to water the aquariums since they're in a closed system.

I've used those heavy rubber foot warmers like you get at the office supply store. They really get warm and the heavey rubber mat is safe from water.

yes, been using both heating pads and 4ft x 5ft electric body warmer
bought at Walgreens for some time i put my trays on the blankets and run at lo, if it gets too warm i put small spacing sticks under the trays. If electrocution or fire was such a danger then why are there washing instructions. Never had a problem

Most of you are in such warm places!

I have a short wooden box lined with plastic. A thin layer of sand and one of those heating coils used to keep ice forming on your roof. Then a second layer of sand. About two inches in all. The trays then sit on the sand. The heating coils have a temp gage so you can set it at whatever you like.
Seems to work out quite well.

I would not use on unless I flat out needed to because of finances. I would use a proper propagation heating mat. That said, I just bought two propagation heating mats and the optional t-stat from IGC Greenhouse Mega Store (url listed below) and love them. The mats I bough will holds four flats each, use 107 watts, water proof, heat 10-20 F° about air temp and cost only $67. They have a smaller ones for $41 that hold two flats. I put some styrofoam insulation down and then the mat set the trays directly on it. Water just runs off and you can roll them up when not in use.

Here is a link that might be useful: Greenhouse Mega Store

If you get a machine washable electric blanket I’m sure it would survive a bit of an accidental dribble from the pots and the damp atmosphere in a grow room or green house with too many issues, after all it can withstand whizzing around in a washing machine.

If one mixes water and electricity one just might light up like RCA.