Germination heat source
 

I have heard suggestions that you could use a waterbed heater for seed germination so I checked around and a friend of mine that owns a waterbed says
the instructions states that you should not turn on the heater untill the matress is full of water so this suggests to me that there should be a mass on the heater to absorb the heat & I don't think that a bunch of small container would provide that mass.The heat range is from 60 to 99 & that makes me believe that a 80 degree setting woud cause any harm even if nothing was on top of the mat except that the mat may have to have something on top of it to pull the heat away from the mat .If anyone has used one of these PLEASE let me know your results.I need cold hard facts 'cause I don't want to hook this thing up & 2 hours later go back & see smoke & flames shooting up to the ceiling from over heating.I have been using small heating pads for years & no problems BUT???.Any bonafied info will be GREATLY appreciated

[QUOTE=durable_now;326274]I have heard suggestions that you could use a waterbed heater for seed germination so I checked around and a friend of mine that owns a waterbed says
the instructions states that you should not turn on the heater untill the matress is full of water so this suggests to me that there should be a mass on the heater to absorb the heat & I don't think that a bunch of small container would provide that mass.The heat range is from 60 to 99 & that makes me believe that a 80 degree setting woud cause any harm even if nothing was on top of the mat except that the mat may have to have something on top of it to pull the heat away from the mat .If anyone has used one of these PLEASE let me know your results.I need cold hard facts 'cause I don't want to hook this thing up & 2 hours later go back & see smoke & flames shooting up to the ceiling from over heating.I have been using small heating pads for years & no problems BUT???.Any bonafied info will be GREATLY appreciated[/QUOTE]

I cant speak about the heater alone. But years ago I did place some plywood over a twin size waterbed and set my seedlings on top of that. It worked pretty good.:D

How many amps does the heating element pull?

This is only my own speculation, but if it is too big of an element what will happen is that the thermostat will click off and on too much and wear itself out. If it fails and sticks in the 'on' position, then that would be bad to say the least. How bad would depend upon how long it took you to discover the problem.

I use an electric blanket and it holds my soil at 78F-80F really nicely on a setting of "8". I fold a twin blanket lengthwise, so it is 30" x 82". I lay it on a sheet of 6-mil plastic and fold the plastic over it so it stays nice and dry.

[IMG]http://imageshack.us/a/img444/3127/elecblank.jpg[/IMG]

I find I can fit seven 11" x 22" trays on each folded twin blanket. The Sunbeam holds 78F-80F really close on a setting of "8". I modified the circuitry on mine to bypass the auto shut-off. You'll have to turn it off and back on every 12 hours, but it is a really economical heat mat. I bought several from the Salvation Army @ $5 each. You can buy a new twin size at $29 from Walmart.

[IMG]http://imageshack.us/a/img571/2845/223gj.jpg[/IMG]

That's a great idea. I tried hot pads, but new ones have an automatic shutoff switch after one hour.

[QUOTE=ScottinAtlanta;326467]That's a great idea. I tried hot pads, but new ones have an automatic shutoff switch after one hour.[/QUOTE]

I have a cheesy operation going on right, my heat pad has a 1 to 5 number
heat setting plus high, with 2 hour and stay on switch

Hotwire, I have read that electric blankets should never be used while folded, and they should not have anything resting on them. This could be a safety issue.

I use a Salton warming tray set on LOW. Since even the LOW setting is too warm for seedling germination, I tone the heat down with one layer of ceramic tiles covered with a pizza stone. The seedlings go on top of all that. I put the seedlings flats in an old broiler pan which seems to conduct the right amount of heat.

I have run my electric blankets folded, wrapped with plastic, and with trays on top for three years, for a month non-stop. I bypassed the off-timer circuit. Electric Blankets have since 1985, had built-in ground-fault circuits (grounded through the neutral side) that shuts down the blanket in case it gets wet, or develops a short, or overloads. I have a k-thermocouple under the center tray, and have never overheated my plants, even on high. The most I experienced was 95F on a high setting for 10 hours. Setting "7" holds about 80F on the Sunbeam blanket. I had the Sunbeam for 3 years now. I start upwards of 20 trays, so I have 3 blankets going for most of February 24/7.

Electric Blankets have a 10-hour to 12-hour auto shutoff. The Sunbeam Twin is 12-hour, and cost me $24.99 at Walmart. I bypassed the timer circuit on mine, but that is not practical for most people.

[QUOTE=ScottinAtlanta;326467]That's a great idea. I tried hot pads, but new ones have an automatic shutoff switch after one hour.[/QUOTE]
I'm struggling with this myself. This is only my second year gardening, and first year trying to start from seeds. Bought two cheap (~$12) heating pads from Wal-Mart, and didn't realize until this morning that they'd shut themselves off, DOH! I did some Googling, and plan to tackle the disabling of the auto-shutoff later this evening, will keep you posted.

UPDATE: Epic fail here....thought I knew which pin to cut, but now have two non-working heating pads. I've ordered two new ones from Amazon, this time getting the Sunbeam 731-500 that doesn't have auto-off. Live and learn.

I use a waterbed heater in my greenhouse and always keep it fully covered with trays. Early in the season this means trays full of extra starter mix that I water just like the tray with baby plants. It also give me a place to put the heat sensor that because my thermostats are old, are the copper tube variety that are obnoxious when putting in with babies.

Having said that, last year for the first time in maybe 20 years, my thermostat ran inconsistently and I cooked my first crop. Soil temp at 112 with room temp at 70, at 9:30 am is trouble!! I knew I hadn't set it up and monitor for enough days before putting seeds out. Just a variable to watch more closely this year.

For years, I started my seeds in my waterbed. I'd start in styrofoam egg carton tops, in bread sacks, in a 10x20 tray w/dome and put them under the covers all day, then slip them in a drawer under the bed at night. I got my quickest sprout rate this way. Never have figured out a good method since I got rid of the waterbed 8 years ago!!!!

KW

i use 2 red color 12 foot rope lights i got half price 3 dollars and 50 cents at the hardware store right after christmas i got a 2 foot by 4 foot piece of sheet rock on top of the lights it holds the temp right a 85 and my peppers love it.

Hi Jack. How much table are you covering with the 24' of rope light?

Since I don't see a way to delete this post, .... I just saw the table size!! 2 x 4 feet.

Is a critical factor that the heats come from below, or just the overall ambient temperature for germinating seeds? I have a chest freezer that I've converted to ferment home beer brew in, in which I can hold temps from freezing to 90 degrees (ceramic heater) w/in 1 degree. I'm going to try seed germination for the first time here soon and was thinking about using the freezer to hold my temps in the correct range. For lighting, I was going to use florescent light inside the freezer. In thinking about the setup, my only concern would be a possible lack of oxygen?

Any of you use, hear of, or think this method would be problematic? Thank you.

JG

Not critical to have the heat source below. Its just usually easier since its the soil that you are trying to keep warm.
Your idea sounded familiar:

[url]http://www.tomatoville.com/showthread.php?t=9979&highlight=freezer[/url]

Should work fine for germination, but you'll want to get them out of there as soon as they begin to sprout.

Jim

I can fit two flats in my oven. It is electric and I just leave the interior light on and it holds the temperature at 82-85. I sometimes leave the door slightly ajar and it still stays nice and warm. Others that gave me this idea had gas ovens. They just let the pilot light be the heat source for them. After they germinate I just put two more flats in. Caution!!! Let family members know so that they do not pre-heat the oven while the plants are inside. I just take the knob off.