Alternative to seedling mat--incandescent bulbs under trays?

15 years ago

I'm a total newb here, so my apologies in advance if this is a silly question!

I'm wondering if I can get around having to buy a heated mat by positioning two (or more) incandescent bulbs under my trays. Would that generate enough heat, do you think? The trays will be sitting on a wire shelf, so the light will shine directly on the bottoms. We have a few clip-on-type lamps that I could just attach to the shelf underneath the trays. The ambient temp of the room (basement laundry room) is probably in the upper 60s, so I'll definitely need to up the temps for germination.

Thank you in advance. I've already so learned so much from these forums, and I can't wait to get started!

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Comments (8)

kandm
15 years ago
I don't use a heated mat to germinate seeds. I am way too paranoid about fire hazards to do it. I think you will be fine if you use low watt light bulbs, a moist enclosed environment like egg cartons, plastic green house or ice cube tray to start the seeds. You can even place the trays on top of the fridge for the same warming effect, or on top of the computer.

Seeds germinate at different rates so you may need to move some under lights while others are waiting to pop. If you try to wait until they're all germinated to move them under lights some seeds will end up really leggy.
kiddo_1
15 years ago
Hi bellamama. Incandescent bulbs could give off way too much heat and could be a danger by 'scorching' the immediate parts of the tray and not move enough heat to the edges.

I have 2 kinds of germinator heat: one I bought for seed germinator and one I built for bottom heat. I always wanted bottom heat for germinating lots of seeds as well as stem cuttings for rooting, but commercial heat mats cost a lot. Here is a link to the 2'x4' bottom heat tray I built for a few bucks. I've used it for several weeks now and I couldn't be happier with it. Good luck with your seed starting!
Kris
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I agree with mandolls....fluorescents don't put out much heat compared to incandescent, but it still puts out noticeable heat which surprised me. I am also a newbie and need to invest in a soil thermometer, but I can tell by experience so far that the shelf I added immediately above my top tier 4' 2 bulb fluorescent light fixtures stays a nice comfortable "warm" and has been perfect for germinating all manner of vegetables so far. You could even box in (or just tent it with plastic) the area above the light and it would become even warmer but that's not necessary for my setup inside the house where the air temp is usually 70-75 anyway. With a cooler basement setup you may want to build a sort of grow box to trap more of the heat rising from the light fixture as your germination station. Now I've just planted daylily seeds on the rack to germinate so we'll see how they do but I expect good results. Good luck with your seed starting!
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"For instance, growing kale seedlings at 80F sounds like a recipe for failure - this is a cool-weather crop which would not appreciate anything over temps in the upper 60s. The same advice applies for growing most vegetable seedlings, including tomatoes." Did you read my previous comment about the effect of light and dark temperature differences on stem length? Did you ever try growing a plant with a higher dark period temperature than light period temperature? I did by growing tomato seedlings with lights on during the night and lights off during the day in a greenhouse. See http://forums.gardenweb.com/discussions/2005610/how-to-easily-supplement-fluorescent-with-incandescent-light. I was struwwelpeter then. I call your attention to the following: "In hopes of keeping plants stocky, I will try to keep the average dark temperature higher than the average light temperature. To do this, the lights are on only from 6 PM to 10 AM. The greenhouse heater is set to go on below 55 deg. F. and the greenhouse ventilator fans and shutter are set to go on at more than 95 deg. F.. I am aiming for 80 deg. F. light temperature and 95 deg. F dark temperature." "To my amazement, these tomato plants are shorter but heavier looking than their greenhouse grown counterparts. The weather was mostly sunny, and, my Gro-Lux bulbs are decades old and used. Who would have guessed?" "Left to right, daylight, Gro-Lux, Gro-Lux Plus Incandescent. You can read the variety on some of the tags. The pots are 4.06 inches diameter at the top outside. http://www.general-cathexis.com/images/BigZac3.6.jpg http://www.general-cathexis.com/images/BestBoy3.6.jpg http://www.general-cathexis.com/images/VelvetRed3.6.jpg The biggest difference is with Velvet Red (which some people claim is the best tasting cherry tomato that isn't sweeter than a normal tomato). This is the first time I have grown it. It is supposed to have bluish foliage and fuzzy fruit."
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jmdj1994
15 years ago
Kris-

That is so cool! What great pictures and instructions--and your "Basement Laboratory" (I like to say that with and evil-ish Germanic accent) looks strikingly like mine! I just got some seeds in a couple of days ago and I think I am going to try that with some old closet doors (the old 70's slider style) for the bottom and some plexiglass like you had on the top. Hmmmm now I wonder if any place still has rope lights...... maybe I could just use my regular Christmas lights instead.........whoo-haa-haa-haa... .......
Anyway you ROCK!

Marie
kiddo_1
15 years ago
*nudging Igor* See. See! There are others out there like us. And they know how to pronounce la-BOR-a-tory. Woohaha!

Marie, yes, Home Depot has rope lighting all year round, back in the lighting/electrical section. As for the bottom warmer, the trick is the styrofoam sheets. The heat can only go UP so the shorter rope with lower wattage works well. Just today I experimented, uh, dismembered, uh you know, cut up some geranium stems to root; I powdered their little bottoms then stuck them there on the heat. *snarkle*

If you can post some pics would love to see your secret lair... ;-)
Kris
thomasshawn
15 years ago
I also happened upon the idea of the rope lights at HD. I have a very similar setup using scrap plywood not foam and I just set the trays right on the lights. I went overboard with lights (2 strands for 3 tray setup and it got a little warm so I added a plug-in lamp dimmer for about $8 also found at HD or L and now I can dial in the intensity and adjust the heat as ambient temps rise/fall. Works very well.

Hope this helps. My setup with 2 rope lights, and a dimmer and some scrap plywood is about $25

Here is a link that might be useful: my post about same issue
melissel
Original Author
15 years ago
Kris, that was really inventive! And I got a good giggle out of the name of your blog, because my name is, in fact, Melissa! Thank you for sharing your info with us.

I went ahead and bought the seedling heat mat because I don't have the time or creative resources these days to build something from scratch (*sadly shaking head*), and I found a decent deal on eBay. I also found the perfect spot in my laundry room for starting seeds, because it offers a light-hanging spot that's just the right size and involves no building, so I had to let the incandescent idea go too. It's OK, though, because the spot (under a work table, right by the outlets, out of the way of the laundry) is so perfect that it will make everything else so much easier!

Thanks for all ideas and discussion, everyone. I've ordered my mat, light setups, and seeds, and now I'm getting ready to start germinating in a week or so!
kiddo_1
15 years ago
Bellamama, good deal. The 'best' method is one that not only works for you, but one that you will enjoy using. Hope you will post some pics when you get rolling. :-D
Kris
kiddo_1
12 years ago
Hi all. Discovered that the link on the thread no longer works. Here's a new link to my my homemade heat tray. I'll be firing mine up within the month.

Kris

Alternative to seedling mat--incandescent bulbs under trays?

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Alternative to seedling mat--incandescent bulbs under trays?

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