Thursday, March 24, 2011

A question for you green thumbs -- heat mat or not?

How many of you use heat mats when starting seeds? And how much of a difference do you see with germination rates and overall plant health?

I have a number of heat-sensitive seeds that I want to start this growing season (last year I bought transplants for those 'tricky' varieties) and I'm considering buying a heat mat. I don't relish the idea of relying on supplemental heat (or specifically, plugging something else in) but we keep our house quite cool, and other low-tech options that I've read about, such as placing seeds on top of the refrigerator won't work as we have a high-efficiency fridge that doesn't put off much heat.

I've read about building a simple light box and rigging it with sockets but I am so not an electrician. Case in point: figuring out the relationship between amps, watts and volts gives me a headache.

I've got my light stand in my office, which has a southern facing exposure, so if it's a sunny day, the space does get warm. But given our weather lately that's a big "if". It also gets very cold at night.

If we had our hoophouse up, we could use solar heat, manure hot boxes and/or supplemental heat, but that's been bumped to our fall project list.

The cost isn't the biggest issue: I've found a mat that comes with a 72-cell tray and dome for $35 -- not cheap, but not bank-breaking either. It's whether this comes under the category of "need" or "want."

Any advice would be greatly appreciated. Thank you in advance, oh wise ones!

18 comments:

Erin said...

The heat mat you found is actually a pretty good price, that being said, if you have the space, the best hands down heat "mat" is a wooden box or plastic swimming pool with a coil of rope lights placed in it topped with sand! It's cheap, and works really well for heat distribution. I only have one small heat mat and use it for my peppers and tomatoes, but honestly only the peppers and maybe some herbs need it. The plant heat mats can actually get pretty hot and dry out the cells so I use a baker's cooling rack on top and place my trays on that or put a towel down between the seed tray and mat. But if you have the room - do the rope lights and that's not a problem, bonus is that you can grow herbs through the winter if you have lights over it.

Fiona said...

Erin -- When you say coil of rope lights, do you mean like the Christmas ones? I'll have to see if I can find them... but this is a great idea. Thanks! My only concern is that we have indoor cats: sand box + 3 cats = YUCK!!!

In addition to tomatoes and peppers, I'm also thinking about my eggplant, leeks, melons and peanuts (this year's novelty plant!), plus some herbs.

Thanks for the tip about using the baking rack and/or towel. Good to know!

Mr. H. said...

Our heat mat is the mantel about our woodstove and it really does help to speed up germination...especially in things like peppers and eggplants. Here is a good article on heat and germination - http://davesgarden.com/guides/articles/view/556/

Mama Pea said...

I've never used a heat mat. My seed starting area has always either been the garage (which had no natural light but full-spectrum lights above the seedlings) and a wildly fluctuating temp provided by a wood stove both day and night OR in a south facing window (with the same full-spectrum lights) in an unfinished room (insulated) that was always cool. (Good gosh, it's a wonder anything has ever made it!) I can't say I've ever had trouble with tomatoes or peppers or eggplant or other sensitive seeds. (Now that all was no help at all, was it?)

Fiona said...

Mr H -- Woodstove mantel... that's a good idea too! We have an old Elmira cookstove and my concern is that the seeds will cook if I put then up there. It gets mighty warm! Something to think about though. And thanks for the article!

Fiona said...

Mama Pea -- that *was* helpful! And it goes to show that with gardening, there is no 'one size fits all' approach.I'm amazed that you've never used a heat mat though, given your garden success. Your thumb must be WAY greener than mine!

Tracey said...

I really enjoyed reading all the comments about heating seeds for germination. We have a glass green house that my husband built[from a huge stack of windows he found at the dump...amoung other things he brings home] to start the seedling plants in before we move them outside. I am on the coast so it really doesn't get too cold here or if it does, it isn't for long.
Warmly,
Tracey

Fiona said...

Tracey -- Glad to hear you're enjoying reading all the comments. I am too! Discarded windows are great, aren't they? I've got some old ones in the barn that I'm going to use to make cold frames and I've seen some great plans for making a greenhouse with old windows and even screen doors. We've still got the cold -- weatherperson says it'll drop to about minus 11 degrees Celsius tonight. Sigh.

Erin said...

The rope lights are lights covered in clear plastic or vinyl, can be obtained at a big box store, some use them for outdoor deck lights, I've never seen them used as Christmas lights but I can see that outdoors, so maybe we're talking about the same thing. I don't need the extra heat for my tomatoes and eggplant, but it does speed up the process. LOL, I can see the cat issue "oh look, mom built us a HEATED litter box!" :)

Fiona said...

Thanks, Erin -- sounds like we're talking about the same thing. I wonder if this would work in the mini hoophouse -- when it gets built, that is. The cats would not be allowed in there!

fullfreezer said...

I don't have a heat mat- although it is a 'wish list' item. I do, however have an ancient heating cable- essentially a rubber coated wire with a thermostat that we got probably close to 20 years ago. I have used it buried in sand- like Erin suggests for the rope lights (brilliant idea although I wonder with the new LED lights if it would work- they're so much cooler)- but usually I just wind it throuh the cells. I do notice a difference with my warm season seeds. I had my first tomato seedlings up yesterday (Wednesday)and I only planted them on Sunday afternoon.
Judy

Fiona said...

Thanks for your comment, Judy! I've read about folks using heating cables. Three+ days for tomato germination *is* impressive! Sounds like you've got a good system going too!

Tiny Gardener said...

I am absolutely a heat mat user. We keep our house quite "cool" in the winter... Ok, it's freakin cold in here!!! There is no way that most of my summer seeds (tomatoes, peppers, etc) would sprout otherwise. I keep my seedlings in the south facing windows throughout the house, but some still need to be under my fluorescent lights. I wish it were sunnier here in Cleveland, but it's winter, and I have forgotten what the sun even looks like...

Annie's Granny said...

I'm using the rope lights for the first time this year, and they are fantastic. They run about $1 a foot. I bought two 6 foot sections, and they can be used separately or fastened together into one 12' light. I just coil one into a box that's larger than my seed flat, and set the flat on top. I planted morning glories and zinnias the other night, and the next morning the morning glories were already up a good 1/2 inch. The next morning all the zinnias were up. Peppers took only 5 days, where they usually take a couple of weeks! Robin has a larger setup (no sand for the cat) at

http://cordarogarden.blogspot.com/2010/11/from-christmas-lights-to-new.html

Fiona said...

Tiny Gardener -- thanks for your comment! It sounds like you're dealing with the same kind of weather as us. I'm sitting in my office right wishing I had a woolly shawl and hat on! Last year my tomatoes & peppers germinated without heat, but they took their time. I think I've decided I need heat; now just to figure out which way works for me. Maybe I'll 'test run' a few methods... I'll keep you posted!

Granny -- hmmm... you're the second user of those rope lights. I'd never thought of them as, like Judy, I would have assumed the LEDs were too cold. But obviously your morning glories, zinnias and peppers think better! Thanks for the blog link -- I'm such a visual learner! This is very neat, indeed!!!

Annie's Granny said...

I put a thermometer in the flat with the plants, and it stayed right around 80F with the rope lights underneath. They are just comfy-warm to the touch.

Fiona said...

Thanks, Granny! 80F is toasty warm. Now I just have to see if I can find some. Stay tuned!

plumbing said...

Conceptually, these products are very similar to electric blankets. They are made of a heat resistance wire that serpentines over a supporting material.

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