I got along fine with a heating cable containing a built in thermostat. I bought a 48 inch long cable drawing 168 watts. I tied it to 1/2 inch hardware cloth with string, being careful to space it enenly over the 4 x 4 foot wire. I laid this on a foam 1/2 inch thick pad and set it on my greenhouse bench. On top a laid a 17 guage aluminum sheet. All my pots for seed starting or cuttings were just set on the aluminum sheet. I used this for about 6 years until I found I needed more space. Al

FWIW: I have the large heated mat, and I like it a lot. It does a good job - seeds germinate very quickly. Mine is being used in a heated (60-70 degrees) greenhouse. Nothing has cooked. I wish I had a couple of them. I put the seeds that want the most heat to germinate on the mat and rotate trays if necessary once seedlings emerge.

^^^^^^^^^^^^^See what I am talking about ^^^^^^^^^^^^^

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The cables are easy to lose -- from year to year, I mean -- think of all the cords you have around the house -- and they are hard to snake. I also didn't feel they got warm enough, but I have nothing to prove it -- like a thermometer LOL! After you get your pattern for the area you want to heat, it is hard to hold them in place. I think you need a staple gun to staple it to plywood or something, but the directions say to use tape, NEVER staples, so I didn't. The tape let lose more than once and I lost my beautiful Serpentine pattern.

As you guessed from my post, I lost my cables when I put them "somewhere safe" and I bought a heat mat and love it, but it was overpriced. LOL! They all are. And mine was 40% off at the Park Sale last fall. It also has hot spots and cold spots, so I put some scrap copper sheet over it to even it out (like Calistoga's aluminum -- both are great conductor's of heat)

I refused to buy the "optional" thermostat that went with it because I felt it should have some as part of the heat mat -- what a scam! I ordered the heat mat and then at the bottom of the screen some items popped up "Other customers who bought the heat mat also bought these three items." What a SCAM! Just talking about it gets me mad all over again LOL! As it turned out, it is working like a charm without a thermostat and without a soil thermometer and I have had very nice, even germination. Even begonias from dust-like seeds!

The good news with the heat mat is it's too big to lose. ;-/

Lime

I bought a few old water bed heaters a few years ago and they are working great. My DH build a wooden box for me and I added sand, then the heater and then more sand on top. It works great and they were really cheap. You need to keep them on almost the lowest heat however. You need to be careful with these. Don't put them directly on wood or set your trays directly onto them. They will melt your trays and could even start a fire. I have also put them between layers of old tile and put the tray on top. That worked well too, but again, on the lowest heat setting.

I use a waterbed heater too. I have had great results with seeds that need warmer soil to germinate. I have a towel, then the heater, then a towel, and then the black trays w/lids. I have the heat probe inside a cup of soil with a lid on it along with the temp sensor end of a cheap digital thermometer(from harbor freight). The cup lays inside the tray. I then have another cheap digital thermometer that the sensor end dangles in the air under the dome lid to monitor air temp too. For my peppers the soil is at 86 degrees and peppers are poppin like crazy. Air temp stay's a bit cooler (upper 70's). As Mary said, the dial on the waterbed heater isn't turned on very much at all.

Sandy

I used a heat cable for years zip tied to hardwire cloth, wooden box with thick styro on the bottom, layer of sand, then the cable/cloth and soiless mix on top of that. Most seeds were up in 2-3 days in the unheated basement. All was fine till last season my new kitties decided this prop box was a great litter box. So now I have switched over to a heavy duty heat mat with wire cage in a wood box for 2 flat starts. I haven't bought the thermostat yet until I do temp trials. So far the lights with mylar and plastic over are keeping the soil temps at 72 but dip to 58 at night, so I will put a timer on the heat mat for when the lights are not running and test those temps.
I had the lisianthus start to pop up in 6 days using this box.

My vote is for the heat mat and the thermostat. If you want total control of your heat, it's the way to go! Park's seed has a combo kit that knocks the price down as oppossed to buying them seperately, you might also find some for a good price on Amazon.com.

I bought a heat mat last year. It was well worth the money. I didn't use a thermostat. I don't really think it is needed. I saw the same mats for a lot more money than I paid.

Here is a link that might be useful: Here is thhe one I bought

I have my waterbed heaters set up on a White Rodgers model # 1687-9 thermostat with remote bulb that is hardwired from the breaker box then from the thermostat it is wired to a recepticle which I have the heaters plugged into then I put the remote bulb in the cell trays thru the top of the dome. It is set to turn on when the temp falls to 80 deg. and turn off if the temp gets around 87 to 89 deg.The thermostat justs cuts the power to the recepticle when it hits the preset temps. This method is working without any problems and the temps are right on the money. I personaly would not use a waterbed heater without a seperate thermostat. Dale

Well Mary you just made my mind up for me! I'm going with the heating blanket! I'm cheap too! *LOL* Plus I have TONS of seeds to germinate and need a lot of room to do it and for me this just might do the trick! There is no way I can afford 20 or so of the heating mats and the temp. controls!I think this will work just fine for me as I have a heated greenhouse going up next weekend, and the fact that I live in Texas! Thanks for the idea!

Roxy_Girl
(Dena)

I had been wondering what to do with that electric blanket I've never taken out of the bag. Now I know. Thanks Mary

Reading these posts just gave me a great idea! I was all set to plunk out the money for seed-starting mats, but was looking for used ones or some alternative. I have a nice warm waterbed (my son's) just sitting there, unused! Can I use it? I can't drain it for the heating pad, but someone's post gave me the idea of just using the bed itself! What do you experts think? Any suggestions on how I can test the temperature and what I'm shooting for? Do I just lay a thermometer on the surface? Sure would appreciate anyone's comments. Thank you very much!

You should be interested in the temperature of the soil. The least expensive way I know is to get a cooking thermometer that has a metal probe and a dial that shows temperatures down to about room temperature. I think the one I have is called a candy thermometer.

Charts show most germination temperatures about 68-85°F. I usually find that two or three degrees above the information printed on the package is just fine.

I'm inspired by the electric blanket and waterbed ideas. Some day I'd heat with cables and a sand box so appreciate the tip about using zip ties and hardware cloth to secure the cable configuration. For now, I only want to start some dahlia tubers into growth for cuttings, and maybe have just a couple of flats of seedlings.

We have three heated bathroom floors with timers and thermostats! Two have floating vanities - I'm going to slide a few trays under the vanities to get things started. Then I'll work on shelving and lighting before moving things to the 10° C / 50° F garage. Fingers crossed!