questions about heating mats

15 years ago

Basically I have two main questions.

what size would I need? I'll be using a 48" grow light,

and somebody said with a 2 foot grow light, I can use

one heating mat; with a 4 foot grow light, I can use two.

My question is for a 4 foot grow light, which size heating mat should I use? Basically I just need it to be big enough to cover the entire area underneath the grow light.

As a result, I need to know what the length and width

of the heating mat would be, that would be a big enough size for the 4 foot grow light.

I would also prefer to get one big heating mat that will

fit under the 4 foot grow light rather than 2 smaller ones, it will just save me money.

The largest I can afford would be the medium-size heat mat, but would it be big enough for a 4 foot grow light?

Here are the sizes:

9" x 19.5" (small)

20" x 20" (medium)

48" x 20" (large)

2nd question; are all seedling heat mats waterproof? I found some on Amazon but it doesn't specify whether they're waterproof or not.

The sizes for the heat mats I've found are:

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Comments (8)

slowpoke_gardener
15 years ago
I bought a 9x19.5 mat from amazon with tray and dome for about $22.50. It is a rubber mat with heating tape molded in, is water proof, but when I placed it on the carpet under shop lights the heat went up to 110 degrees by the next morning. I am going to run it through a light dimmer switch to lower the heat. Just sitting in on a table top will help lower the heat.

I would advise using a therometer to make sure the heat is in the range you want.

Larry
gnhelton
15 years ago
I canÃ¯Â¿Â½t tell you whole lot because this is my first buying a heating mat too. But what I did find was the Hydrofarm listed on Amazon and it gives a little more information. Plus the guides are listed as pdf at the bottom of the link.

Here is a link that might be useful: Seedling Heat Mat 9
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dsb22
15 years ago
kawaiineko,

4' is 48" inches. So the large mat that is 48" long is the best fit for covering the entire length under a 4' light. The medium length of 20" is going to leave you with a lot of unheated space under the lights. This could work for you, however, if you put the seeds that have not germinated yet on the mat and the seeds that have germinated in the unheated area. Once seeds have germinated, they no longer need the heat mat.

The Hydrofarm heat mat I have seems to waterproof to the extent that a little water or condensation on it doesn't cause any problems. I'm sure it wouldn't be a good idea to submerge it.

Larry, the Hydrofarm heat mat thermostat that I've been using is working really well to keep my mat from getting too hot. Whenever the mat reaches the temp I've set it at, the thermostat turns off the power to the mat. I think this will prolong the life of the mat too.

http://www.amazon.com/Hydrofarm-MTPRTC-Digital-Thermostat-Heat/dp/B000NZZG3S/ref=sr_1_1?ie=UTF8&s=home-garden&qid=1298557084&sr=8-1
razkeys
15 years ago
I've used heating pad for your body. A LOT cheaper and you just have to be careful when you water, but I have even gotten them wet but would not recommend that. I'm also thinking of using an electric blanket. I am trying to burn m y house down? Anyone have an opinion?
calistoga_al ca 15 usda 9
15 years ago
Many heat mats are made with a thermostat as part of the mat and are usually permanently set for about 70 degrees. Al
obrionusa
15 years ago
Razkeys, I use a heating pad to start my seedlings and it works a charm. I think a heating blanket is pushing it though. I put my seedlings on a cookie sheet to keep the water contained and off the heating elements of the pad. I picked up more stuff for seed starting at goodwill and other thrift stores.
slowpoke_gardener
15 years ago
Right now I am using my home-made heat mat(9"x13" cake pan) with Christmas tree lights under it. I only have one 9 cell in it now. I can look over on the bookcase and see it is 76.1 degrees inside(transmitting therometter) and can addjust up or down as I see fit. The major drawback is that I have to have an extenion cord running to it from the switch I have set by my recliner.

I have a Hydrofarm 9.5x19.5 mat that gets too hot, but I will fix it like the homemade (pan) by using a dimmer switch on it. The home made runs about 85 degrees at 80 volts (temps vary with ambient).

I like having a small heatmat (pan) and just sticking 1 or 2 cell packs in it and sliding it under or behind the chair
and just glancing over my left sholder to check the temp.

Larry
obrionusa
15 years ago
Here is a something cheap to make and I got all the stuff at Lowes. I made this last year and it worked good. Its nothing but a 5 gallon bucket and a light socket. I dont keep my seedlings in there after they are up because of no air movement.
Check It Out!

Here is a link that might be useful: CFL bucket