Heating mats for seeds..

Who has them? Who uses them? How much were they to buy? And, where'd ya gittum?

BackyardBirdGardner wrote:
Who has them? Who uses them? How much were they to buy? And, where'd ya gittum?

I do. Still me. About $35CAD including a Jiffy cell tray and 72 peat pellets. Home Depot in Canada.

I just started using a heat mat this year. I am currently attempting to germinate some artichoke seeds on it. Twiddling my thumbs waiting to see if it works.

I do!! I had no luck at all germinating tomatoes without it ! I ordered mine from Burpees for about $35.00.. Sadly ..I can no longer reccomend Burpees. My son ordered me a gift card for Christmas and I STILL don't have it.. they keep giving him the run around..

I just bought one this year (about a month ago). I got mine from Amazon see link here - hydrofarm the 20 x 20. it was about 35 bucks, fast shipping. So far so good. I didn't get the thermostat, I have it plugged into the timer that turns my lights on and have a plastic bin on top to sort of keep the heat around the plants. The plastic bin is propped up, otherwise it might be too hot and humid.

When it came it was rolled up, just put a few rocks around the outside and it flattened out in about a day.

I had been watching my temps for a couple weeks in the basement near the starting station. 61F most times, but would dip to 59F. No biggie for lettuce, cauliflower, broccoli. However, not good when I get ready for peppers and tomatoes.

My seedlings were getting a bit leggy. I move them much closer to a brighter window because I figured it was the lighting, but also read a possibility was improper heating. So, when I jammed in the rest of the lettuce (started about 30 peat pots yesterday), I felt I needed to move the thermometer to monitor the soil temps. When I did, I was shocked. 61 my booty. The temps dropped to 55-56! I'll never get peppers at that rate.

So, I bought one and just plugged it in today. We'll see how it warms. It says 10-20F above ambient temps. Fine with me. Getting to 75 would work out really well for me.

My next step will be to wrap with reflectors and/or foil to bounce all my light around and max out it's potential.

Thanks for the replies.

OK... I'm new, but I'm a research freak....

There are commercial mats and consumer mats... Commercial mats are often/usually very large and generally quite a bit more expensive... If you have the room and $$, they will typically perform better and last longer...

Then there are the consumer grade mats... that's what I am using because of $$ and I need smaller mats (for now).

I AM using them... I bought a HydroFarm 20"x48" to do 1/2 of my 8'x2' grow shelf. I got the HydroFarm controller as well. At some point, I am seriously considering adding 5 ea. 9" x 19.5" mats to cover the other half of my shelf with each on its own controller to offer custom "per flat" warming.

As I understand it, you need to correlate your controller thermostat settings to "real world" as there is often some considerable variation. (IAW... measure with a thermometer at different controller settings and make a chart for conversion.... I'll post mine as an example when I do it.)

Another key to making your mats work properly is "thermal transfer"... There are a LOT of variables here (I am an amateur thermal engineer type.... computer overclocking, et al.), but I am only addressing the MAJOR ones that affect us as gardeners...

1) Heat loss below the mat... You stand to lose a significant portion of your wattage through the bottom of your mat unless you guard against it... You should put some kind of reflector/insulator UNDER your mat... I plan to start by simply lining my shelf with some of my leftover Mylar reflector sheeting as my current shelves are MDF (medium density fiberboard) which is a terrible conductor of heat/pretty good insulator. When I upgrade my shelves to metal panels, I will switch from mylar film to something like a Mylar/air bubble/Mylar composition sheeting...

2) Ambient heat losses... less important but still significant... if your grow shelf/area is exposed to temps below your mat set point, you will lose heat... the amount depends on the temperature spread, air flow, and temp of moving air. bigger spread = more heat loss.

3) Conductivity - To get the heat FROM the mat into your seed/seedling grow media, it has to transfer from the mat, through your flat tray (if any), seedling pot (if any), and any other layers of material between the mat and the grow media. The more layers, the less efficient the transfer. The less conductive the material the layers are made of, the less efficient the transfer. The smaller the contact area between the layers, the less efficient the transfer...

4) Soil moisture... the higher the moisture content, the more efficient the heat transfer to the grow media and thence to your seed/seedling. (consistent with not having it TOO wet).

Or you can completely ignore my comments if efficiency and power use are not concerns for you...

I got mine today from Amazon. Hydrofarm 9 x 19 1/2 for $18.73(I only have a small space to use for starting seeds). I also got the thermostat, partially because I can see it being used for things when not starting seeds. We often are trying to save baby birds and animals that need some supplemental heat. This would work so much better than a heating pad or heat lamp.

I don't how accurate this is, but it gives an idea.

Out of curiosity, I used my electronic meat thermometer to measure the temperature of the soil that I sowed my artichoke seeds in on the heat mat. It read 82F. My room temperature right now is 72F, so it is heating up the soil to about 10 degrees higher than the room temperature. Because the seeds haven't sprouted yet, I still have the dome on the tray and have some nice condensation on it. The soil blocks are nice and moist, not too much though. I actually haven't had to water them since I planted them a few days ago. The heat and condensation seems to be keeping them moist enough.

I hope this helps a little bit for gardeners thinking of buying a heat mat.

I found that the actual gardening heat mats seemed too expensive to buy.

My hubby bought a new heating pad with a timer for use on his knee and back, so I am using his old one under my seed dome tray.

It works well on the low setting.

I found that I have to check that the soil in the peat pots as they dry out in a couple days if not misted regularly, when using the heating pad. Don't be fooled by all the moisture droplets hanging inside the dome, they can be present even when the peat pots are very dry. I mist them every day with mist bottle.

bullfrogbabe wrote:
I found that I have to check that the soil in the peat pots as they dry out in a couple days if not misted regularly, when using the heating pad. Don't be fooled by all the moisture droplets hanging inside the dome, they can be present even when the peat pots are very dry. I mist them every day with mist bottle.

Thanks bullfrogbabe... I have been checking the blocks regularly to make sure they are not drying out. They are still quite moist from when I made them and sowed the seeds.

Just curious.... Why would you mist from the top, when you could water from the bottom? Doesn't peat act like a wick?

cautery wrote:Just curious.... Why would you mist from the top, when you could water from the bottom? Doesn't peat act like a wick?

peat can wick however, soggy pots = rotten seedlings and mold.

I used an old heating pad for my hubby's back, too! It seems to do pretty good. I also got a "greenhouse" Shelf thing from Farm & Fleet for $25. It has 4 shelves and a clear plastic cover with a zippered front. It's about 5 feet tall.
I've never started seeds before so we'll see how it goes.

got it... of course. Thanks!

camprn wrote:

cautery wrote:Just curious.... Why would you mist from the top, when you could water from the bottom? Doesn't peat act like a wick?

peat can wick however, soggy pots = rotten seedlings and mold.

Here's my little update fwiw.

I plugged the thing in and just set it on a tv tray (wooden) with the flat directly on top. It boosted the temp about 18F within a few hours and flattened out nicely. My basement runs between 55 and 59 with wet soil and my meat thermometer stuck in there....which was shocking because the straight air temp was a consistent 59-61F for days.

Anywhoo, I now see 72F every time I look. My lettuce (Simpson's Elite) sprouted in the 59ish temps in about 4-5 days the first planting. Two days later, I have my next shot of Salad Bowl already poking heads. So, it's definitely effective.

However, I am trying to watch and see if it helps with a little of the legginess. And, I can't really tell anything yet.

And, my celery is going on it's 3rd week and nothing. I know to be patient with celery, but this bump in temps oughta bring something out of that pot. In about a week, I hope to see something. If not, I will just plant some more, and this time, drop about 4-5 seeds in that pot...in case its a 25% germination thing.

Bottom line: I really notice a difference, and can't wait to get the toms and pepps going now.

It's nice to hear that the mats are effective and you can see the difference in seddlings grown with and without the added warmth.

Give the poor celery a chance, it really does take quite a bit of time to germinate.

I love to watch Garden Girl, the link below has a short clip using a hot house with a heating mat to start seeds indoors.



https://www.youtube.com/user/GardenGirltv#p/a/u/0/25curpf_NfU

Furbalsmom wrote:It's nice to hear that the mats are effective and you can see the difference in seddlings grown with and without the added warmth.

Give the poor celery a chance, it really does take quite a bit of time to germinate.

Of course, when I went downstairs this morning, I had celery...lol. I planned to be patient. But, again, the heat mat, no doubt, helped things along. It's still a comfortable 72F on the mat.

And, today, since it's been 3 weeks for the first starts, I diluted a little fish emulsion and dropped it in all of my seedlings....even those that just popped up yesterday. 5-1-1 can't hurt too much, and it may strengthen my leggy lettuce a little since the lettuce still has a ways to go before I up-pot them and put them in the window.

I plan to start another celery this week and see if it doesn't come up faster....which I know it will.

If you can find an old waterbed heater those work just as well.....and have a thermostat too...

What a good idea! As I remember it, those heaters were capable of some pretty fine control too.

sceleste54 wrote:If you can find an old waterbed heater those work just as well.....and have a thermostat too...

Home made heating mat idea
http://www.vegetablegardener.com/item/11658/diy-heat-mat-speeds-seed-starting

That's a good idea! I used a heating pad this year!

camprn wrote:Home made heating mat idea
http://www.vegetablegardener.com/item/11658/diy-heat-mat-speeds-seed-starting

I followed these instructions last year and made this. I recommend it.

Squat,
Did you have any probs with too much heat ?

My 36 foot rope lights are 300 watts each which to my mind will cook the seeds and seedlings .
I have now opted for a 16 foot trace heat cable ( made into a big sine wave pattern ) at around 7 watts per 3 feet and a programmable probe thermostat set up ,

camprn wrote:Home made heating mat idea
http://www.vegetablegardener.com/item/11658/diy-heat-mat-speeds-seed-starting

I dont know if it was the same guy or not, but I saw one of these homemade mats made from string lights on the interweb. Worked fine, but the guy did say he modified it so that one string of the rope lights lit just one of his seed trays. That way, if he wanted to plant seeds at different times, he wouldn't have turn on all the lights...just the corresponding string.