Xmas Light Seedling Heat Mat

[TomatoDon]

Just wondered how well the heat mats work. Last year my seedling tray seemed to stay too cool, even in a heated room. Naturally, I suspected this slowed down my germination and growth rate. The room temps were comfortable, but the trays just seemed too cool most of the time.

Does anyone here have advice or experience with heat mats? I see some 20 x 48 inch ones in the Park catalog. But it doesn't have a thermostat and says it doesn't need one. Do any of you know what the temp is set to and do heat mats really make a significant difference?

Thanks!

Don

[phreddy]

No help with the question Don but I sprout my seed on tissue etc and put the bag on the back of the 'fridge to add the required warmth. After sprouting they don't need the heat

[TomatoDon]

Good point. Is a heat mat needed after germination?

Don

[phreddy]

It will depend on the temp where you keep the seedling but I have seen a chart somewhere giving 'best' temps for germination. I will see if I can find it.

[Granny]

Originally Posted by TomatoDon

Just wondered how well the heat mats work. Last year my seedling tray seemed to stay too cool, even in a heated room. Naturally, I suspected this slowed down my germination and growth rate. The room temps were comfortable, but the trays just seemed too cool most of the time.

Does anyone here have advice or experience with heat mats? I see some 20 x 48 inch ones in the Park catalog. But it doesn't have a thermostat and says it doesn't need one. Do any of you know what the temp is set to and do heat mats really make a significant difference?

Thanks!

Don

We started several hundred plants last year, mostly peppers and tomatoes. The only place in the house that we have to put large numbers of seedlings is in our "winterized" back porch schoolroom, which runs cool enough that I often turn on a space heater out here early in the mornings. (Warm here in VT at outside 33F right now)

I used a trick that Thompson & Morgan gave out years back when they were first starting to sell in the US and used to send you practically a free book if you ordered from them, since it is the only way I have ever managed to germinate seeds.

Use moist but not wet sterile seeding mix. Put the flats/containers of seeds you want to germinate into a plastic ziplock bag, then open the end of the bag the first second you see cotyledons popping through. I can't recall anything that took more than a week to germinate and at least one came in at under 2 days.

I can't germinate a seed in a Jiffy pellet to save my life (lost nearly all the peppers that way last year! - daughter thought they would do just as well as sterile seed starting mix) - nor any other way I've tried other than this, for that matter.

I have thought about sacrificing the use of the heating pad intended for my "lumbago" (which I suspect is all these germination heating pads are - just black with no or a slightly different controller) for a week or so, setting it on low and propping a flat a couple of inches over the thing for the peppers. We'll see how they germinate in the plastic bag first though I think. Last year's second batch of peppers did just fine by the plastic bag method.

[tomatoaddict]

I only use a heat mat for my peppers, not my tomatoes.
I use a regular back heating pad set on low that does not have an automatic shut off. Cost like $6 dollars. I don't think you need to invest in an expensive grow mat. It works for me.

[cottonpicker]

I routinely use an ordinary heating pad from the drugstore to start my tomato & pepper seedlings. I cover it with aluminum foil to prevent accidental contact with water, turn it on low or medium setting and set the seedling flats directly on the pad. I fully agree-- there's NO need to purchase expensive & special heating pads for starting seedlings.
LarryD

[bcday]

I check the soil temperature with the type of cooking thermometer that has a thin pointed probe. What felt barely warm to me turned out to be almost too warm for the seeds.

The description for one seed-starting mat said it didn't have a thermostat but was designed to keep the soil temperature 10 degrees above the surrounding room air.

The ordinary heating pad I have gets too hot to set the seed tray directly on the pad. I have to elevate the seed tray an inch or two above it as Granny said. I finally got tired of messing around with that setup and invested in a real seed-starting heat mat.

[shelleybean]

I use a heat mat from the nursery made for starting seeds. It has no thermostat but is supposed to stay between 80 and 85 degrees, I believe. I've never thought I needed it for tomatoes because they sprout easily indoors for me, but the heat mat really does speed up plants that can take longer to germinate. It's great for peppers and especially parsley, which can take up to three weeks to germinate. I also use it for eggplant since I start those seeds at the same time as my peppers. Last year I used it for tomatoes and basil, too, since it was already out and set up. Some of my basil germinated in less than 48 hours.

[gssgarden]

I've used a mat for the last four or five years with great results EXCEPT for the first year when I cooked my little seedlings because I didn't prop up the plastic dome for ventilation. My mats do not have a thermostat or timer.
Remember, you can put your cherry seeds in a few days later than most. Mine always seem to be the first one's up and the fastest growing sprout. They'll get leggy quick.

Greg

[greggf]

I have a heat mat, but it doesn't seem to help tomatoes any - they sprout fine on their own at room temp, at least for me. In other words, I don't think they're a panacea.......

=gregg=

[natural]

I have used the expensive heating mats for a few years now. Started 5000 tomatoes last year. I like them, but 2 of them suddenly stopped working.

The single tray size mats do not heat the trays evenly. The 4 side edges are definitely cooler than the middle, causing uneven germination rates.

I have also cooked some seedlings by not venting the dome.

[shelleybean]

I do agree that the edges of the mat are cooler than the center. Luckily I haven't cooked any of my plants but I'm a SAHM so I am able to check under my domes several times a day if I need to. I just pull out each pot as it germinates. If I were away at work, this could be a problem.

[bcday]

I noticed the problem with uneven heating too. But since I was already checking twice a day (or more, LOL) for new sprouts, I just rotated the cells on the mat at the same time. The ones that had been in the center got moved to the edge and vice-versa. The question for me is whether the warmer-cooler-warmer cycles made them germinate faster than not being on the heat mat at all.

[Deer Park]

I use the 48 x 20's in the garage on a sheet of plywood and quarter inch foam since my wife kicked me and my seed starting trays out of the house a few years ago.

They work great for me. My lights are hung just above the mats with foil covered cardboard sides leaning up against the lights.

Michael