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Re: Okay, serious stuff

I think, contrary to conventional arithmetic, that a $50 heat mat would be cheaper.

On Wednesday, March 9, 2005, at 10:46 PM, Kitty wrote:

Thank you, Donna, for watching out for us. this reminds me of a recent
forum posting I read (BTW, he is talking Celsius):

I thought I would share a couple of inventions with you folks and see if
anyone has any other interesting ideas...

Bottom Heat
Trial one - Failure DON'T DO THIS!!
I had read that a waterbed heater set to its lowest setting worked fine as a
heat pad for seedlings. In the spirit of adventure, I bought one at a yard
sale in the fall (fifty cents). A couple of weeks ago it was time to test
run the heater. I set it on the Ikea (wooden) racks in the basement, then
placed a boot tray on it, and on top of that a flat filled with seedling
soil. I stayed near and babysat it while doing laundry. The basement is
quite cool, and I went upstairs once I got cold, and then forgot to check
back in on the heat setup.

Sweety and I went shopping and got home about an eternity later.

When we got home I could smell the distinct scent of burnt plastic.
Downstairs the waterbed heater had melted through the boot tray, the bottom
of the flat of soil, and had melted away all the plastic covering the heat
coil. The Ikea shelves are permanently charred. Idea Abandoned as hopeless.

Trial Two - Partly Successful
While cleaning up the mess from trial one, I came across a ceramic
construction heater in the basement, and began work. I made a box out of 1"
thick barn board I had as scrap lumber. across the top I used strapping as a
frame for the flats to sit on. The fan sucks air through an opening in the
frame and heats up the space inside the frame.

I set the box on top of sweety's sewing table ...I wonder if it will get in
her way... plugged in the heater, and watched what happened. my soil
thermometer was registering 12 degrees when I turned the heater on. Once I
had the flats across the top, preventing the heat from escaping the soil
thrmometer began to climb.

I wasn't distressed until the soil temperature was up to 26 deg. then the
first flat began to deform and melt. After I unplugged the fan, the
temperature continued to climb. I don't remember what the top temperature

Trial 3 - Nearly there
By opening vents on the side of the box (OK, Holes) I was able to reduce the
internal temperature of the box. Sadly even with the heater set to its
lowest setting, things are melting.

I have now installed a heat-shield (piece of rigid dryer venting flattened
out) under the flats. This seems to have reduced the risk of flats melting.
They are no onger gooey. New flats have been installed, and an insulating
layer of cardboard has been installed under the flats. Total project cost so
far is $4.00 to replace the melted flat. The temperature still gets above
20, but no longer gets hot enough to melt things. more vents will be added.

What do you think, Donna?

neIN, Z5
----- Original Message -----
From: "Donna" <gossiper@sbcglobal.net>
To: <gardenchat@hort.net>
Sent: Wednesday, March 09, 2005 8:00 PM
Subject: RE: [CHAT] Okay, serious stuff

Grumble, grumble.....

Anyways, if you are going to continue to this stuff.... do note they have
special types of power strips, where the plugs are correctly positioned,
well as spaced for those power transformer plugs. It also comes with an
overload protection circuit *per* outlet... so something's plugged in will
continue to work while others are stopped due to a fault/trip.

Yes, they do cost more, but isn't it worth it? Nevermind....

On another note, cyberguys (a website) also sells plug extenders, so those
bulky plugs can use a regular outlet.


I know all of this is
probably making Donna cringe, but it has worked fine for years.

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Island Jim
Southwest Florida
27.0 N, 82.4 W
Hardiness Zone 10
Heat Zone 10
Minimum 30 F [-1 C]
Maximum 100 F [38 C]

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