Heat from propagation cables

I'm curious to know how much heat is dissipated into the air from propagation cables that have the built in thermostat controls. Does anyone have knowledge or experience with these?

I don't know how much heat goes into the air, but i have some seedlings on a heat mat. I've got a small (6' x10') portable greenhouse. the heat mat is in an "under bed" storage box lined with ridgid foam. This has kept my seedlings from freezing when it got down to about 22F. At night I throw remay over it to help keep the heat in. My hubby said he thought the heat mat would probably keep the whole greenhouse from freezing but I don't know. I too, would be interested in anyone elses experiences.

Hi skyeblu,
I just ordered propagation cables in 17 and 26 foot lengths. These cables can so under pots or directly into the soil. There is an automattic thermostat that controls the heat. The rigid foam insulation under the soil is a great idea and I'll add that information to my journal. I want to get a jump start on plants especially veggies to see if I can get a bumper crop this year with at least 2 harvests.

im wondering if my lizard would miss he heating pad much! ;]

I've used those cables, sometimes work well and sometimes not. That's a great idea, the under bed box, skyblu. I've used the cables directly on a table and sat the flats right on them, and also have buried them in an inch or so of dirt and sat the flats on the dirt. Both ways worked fairly well. When setting them directly on the cables (no dirt) I still used a solid bottom table instead of a wire-top table...seems like the thermostat seldom kicks off when exposed to the cooler air coming up thru the wire.
Also, most of those are automatically set to provide heat to 74º but only if the ambient temp is no lower than 50º.

As for your lizard dori...hehehe, maybe he could stand guard and eat the nearby aphids and white fly!

Horseshoe,
I'm going to try them both methods, under the pots and directly into the soil and see which method works best. For sure I'm going to use the rigid foam insulation for heat retention. Thanks for the advice on the ambient temps. I have a room that I keep the temps really cool since its rarely used except for plants.

Heated 'plant feet' will allow a plant to survive ambient temps that are normally too low for the species. Depending on your temp I don't think the cables will heat the air much, you really have to touch the cables to feel the heat.

Dennis,
Thanks for your information, that's good to know.

(Shhhh...Dennis discovered I'm a miser! Those cables sure keep the heat bill down in the ghouse. Much cheaper to heat the soil than to heat the whole ghouse.)

Joydie, if someone ever asks you what you would like for your birthday/Christmas/holiday ect, tell 'em you'd like a rubber heat MAT, w/thermostat. Those can really be better regulated than the cables. The thermostat will go from 50 to over 100 degrees, depending on your setting. (They cost quite a bit more tho, but will last a lifetime.)

LOL, I'll keep it a secret.

Horseshoe,
I considered those before I got the cables. I wanted to use the cables to extent my growing season outdoors in addition to growing seedlings.
My Mother's day gift requests
#1-Plastic Row Cover kit
#2 Super red mulch plastic

Birthday-May
#1 Five cubic foot bag of loam for raised beds

Just Because I Love You Mom-any day of the year LOL
Contributions towards LUMBER
Timers
Misting system
Automatic venting Kit
Anything that I need for a greenhouse!!

Goonness gracious! You're on the ball, Joydie!
Sounds like a great wish list! May it all come true! :>)

Thanks horseshoe, can't help but dream...lol...it may never happen...lol.

I maintain my green house temperature at 50F during the winter months.

When building your heating bed, the rigid insulation up the sides of your box to the soil depth, as well as under the box, will help maintain the temps at the edges and make your cable work more efficiently.
Tenting the sides and top of your structure with plastic will also help retain the heat but remember to vent the area occasionally to prevent the formation of mold and mildew.

My coil is 48' long and holds the temperature of a 12 square foot area at 72F ( when it functions correctly) so I made my heating bed 3' X 4'. It uses 168 watts of power so if it runs 24/7, it costs me $5.00 a month at our current price for a Kilowatt hour . They really are quite an efficient way to extend your growing season.

I just had to report, It got down to 9F last night. I had rigged a way to tent the remay,over the heat mat, so I threw a double layer of bedsheet over the top yesterday. The sun was shining bright this AM when I went out to check if anything survived. Well, it was 60F inside.the greenhouse. All the seedlings were fine, and the seeds I had planted friday were sprouting. I'm really jazzed. Bet you can't tell this is my first year with a greenhouse, huh?

Hi This is my first day here. I would like to know more about the lizard. Linda

Ruth Ann,
You are just down the highway from me. When I had all my windows in the house replaced with thermal ones I kept the old single pane windows and the storms and screens. I will use these for the cold frames.

Lee Valley in Burlington has an item that looks great. Its on page 14 of their catalogue and its a heat activated Window Opener. It has a gas chamber and as the temperature rises it opens the windows to drop the heat and then closes them again to maintain equalibrium in temperatures. It will support a 15 pound window and my windows will be within that weight average or below. It will be easier on me than going back and forth outdoors to check the temps in very early spring and late fall months.

You can order their cataloque at http://www.leevalley.com
its worth it. They have lots of great items for gardeners and greenhouses.