What to use for bottom heat source for seeds?

ditnc(7 NC)February 8, 2011

I got my shop lights today, and have my shelves and a large oscillating standing fan. And I got my seeds and planting mix.

Now I just need to figure out what heat source to use for my seeds. Can someone suggest some inexpensive ideas? The room where I will be growing these seeds has a south facing window, but is kept around 66 degrees. So I think the plant trays will need a heat source.

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Hi Dit, you only need heat (70 to 80) to get seeds up, 6 to 9 days. After that 66 is a good temp. I and some others use a cold period.6 to 9 days at 55 or there about after you get a good stand Makes plants stronger and not leggy. Heating pad works just fine to start seed, remember to put it in a water proof bag to keep it dry. I use a plastic pillow case. Good Luck Bill

    Bookmark   February 8, 2011 at 8:42PM
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Lots of different heat sources out there. But if ya shut that fan down and keep yer germinating trays covered in plastic wrap close enuff to the flouro bulbs u might not need any heat source other then the bulbs.


    Bookmark   February 8, 2011 at 8:44PM
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If you cover your setup with one of these reflective mylar film emergency blankets the lights themselves may generate enough heat to sprout your seeds.

    Bookmark   February 8, 2011 at 8:46PM
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leira(6 MA)

I use heat mats that are designed for the purpose. They're often very expensive, but I've occasionally seen them available quite cheaply (like right after I've purchased all I need at a higher price).

On the plus side, they are the size of a flat, they produce the right amount of heat, they aren't damaged by water, and once you buy them, you'll pretty much have them forever.

While I do love my heat mats, I'll go with others and say that they aren't strictly necessary under most circumstances, though.

    Bookmark   February 9, 2011 at 3:34PM
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A seedling heat mat or a heating pad works really well. Tomato seedlings grow best with a consistent room temperature, about 70F -- since you keep your room at 66F, you'll need a little more heat. If your tomato seedlings are near a window, watch for drafts. Cold air mixed with over-wet soil is a deadly combo for seedlings. They'll dampen off or develop nasty fungi faster than you can say "transplant time."

Here is a link that might be useful: What tomato seedlings need after they germinate

    Bookmark   February 9, 2011 at 5:38PM
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Tomatoes aren't so needy about bottom heat, unlike, say, peppers, for which it's a must.
When I do use it, I also use a human heating pad wrapped in watertight plastic. They do sell specific heating pads for seedlings, but they are WAY expensive, $35-$50 for a single-tray-sized-one.

Carla in Sac

    Bookmark   February 9, 2011 at 5:51PM
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natal(Louisiana 8b)

I've used the top of the fridge for the past 15 years. Bought a seedling heat mat when we were remodeling the kitchen and putting in a built-in fridge, but since we also needed a small fridge for the temporary kitchen I still use it for germinating.

    Bookmark   February 9, 2011 at 7:44PM
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gardningscomplicated(southeast michigan - 5b or 6?)

I was gonna say top of the fridge too, for germinating. Unless you have too many, and they won't all fit. But you can build a simple shelf to make more room. And then stagger the planting, so they don't all need heat at the same time.

    Bookmark   February 9, 2011 at 8:46PM
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ditnc(7 NC)

Forgive this very basic Q (I am the OP for this thread). Can I just use the heat (without lights)from the refrigerator until the seeds germinate and then move the flats to the lights? If so, I can stagger multiple batches. I have time.

OR do I need the lights and heat concurrently for the seeds to germinate? If I don't need the light until after they sprout, the top of the refrigerator will work! But there is no light or space to put any lights above the refrigerator.

    Bookmark   February 9, 2011 at 10:43PM
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gardningscomplicated(southeast michigan - 5b or 6?)

I'm almost positive tomato seeds don't need light to germinate. But as soon as they start coming up, they need light, or they'll grow too fast trying to find it on their own. Last year, I put mine in direct sun right after they sprouted, and I didn't have to harden them off. Similar to what happens when you plant them outside. But if you're in a cold climate, you need something like a tunnel to keep them warm. Or bring them in if it's gonna get too cold.

...I just googled it, and tomatofest says they don't need light to germinate. I posted a link below.

Here is a link that might be useful: seed starting

    Bookmark   February 9, 2011 at 11:21PM
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I'm in Texas and the temperature is 80 one day and 20 the next. My light set up is in the garage, where the temperature is controlled by the weather.

Usually, I'd start my seeds in the pantry on a shelf. It is the warmest room in the house. This year, I just left them in the garage because the shelf I usually use had the wife's stuff on it. Gotta pick your battles, and this was not the time or issue for this battle, so they stayed in the garage.

After a few days, I grew impatient and moved some of the cups upstairs (where it's warmer) and placed a few cups on top of my computer that is kept in a hutch. Others were placed in a glass cabinet lit with an incandescent light bulb (seeds were not germinated so the light was just for heat). Within two days, the seeds started to pop up. I took the ones that had started and moved them to the garage under the lights and replaced them with seeds in the garage that had not come up yet.

By the time I had rotated about 3/4 of the seed cups to the heated spots upstairs, the rest had germinated right there in the garage. So it appears that the heat helped them germinate faster, but was not necessary for germination.

    Bookmark   February 10, 2011 at 9:13AM
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Just place your starter seeds on top of the fridge like natal and gardeningcomplicated indicated. As soon as you see the seedlings breaking ground place the entire tray under shop lights. Keep the tray covered lightly with plastic film and I use toothpicks to allow the seedlings to grow up during that 1st week and remove the plastic and the end of the week.


    Bookmark   February 10, 2011 at 9:30AM
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I just got my latest issue of Fine Gardening.The tip that won in this issue addressed this problem. The person took a plastic sweater box and put a few strands of mini Christmas lights in the box and set his germination stuff on top. Says it worked well with no extra expense, since the lights were lying around anyway.

    Bookmark   February 10, 2011 at 10:57AM
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I germinate my seeds in my old fashioned gas oven. The pilot light keeps the interior at about 95 degrees with the door shut and about 75 to 85 with the oven door cracked open about two inches at the top.
As soon as the first seed sprouts I put the whole container including yet unsprouted seeds outside in full sun if it is above 50 degrees F outside, or under my fluorescent lights if it is cold outside.
If you leave the sprouted seedlings in the dark a few hours too long they will grow too lanky and have long weak stems.

    Bookmark   February 10, 2011 at 11:50AM
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I start my seeds in a room where the temp ranges from 62-65 in the winter. I place my seed flats in a 1020 tray and cover with a dome. I place them under the lights as close as I can for 16 hours a day. My tomatoes are up in 3-4 days. The domes help keep the heat and moisture in. I lift one corner when the first seedlings pop up and remove the cover when most have germinated.

I started some onion/leeks seeds last Friday and had sprouts by Monday. Almost all of the seeds are up now.

This method works for all of my seed starting. I have an unused heat mat - a gift from a few years ago.

    Bookmark   February 10, 2011 at 1:20PM
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I start lots of seeds every year and I don't own a heat mat. I have a stainless steel storage shelf, and the three center shelves have a light set-up with two fixtures each shelf. The top shelf has no lights but is wrapped in a lightweight mylar blanket that you can buy in the camping dept at WM for under $3. I wrap one blanket around three sides of the shelf to reflect light back to the plants. The top shelf I totally cover with another mylar blanket so that the blanket hangs down to the light on the second shelf. The heat from the light rises and heats this area like a little germination chamber. When the VERY first sprout appears, I remove the dome and move the tray to a light shelf, then start new trays on the top again.

I hold the blanket in place with clothes pins and if it is too warm inside the germination area, I just lift one side and clip it up. The lights are on chains and small hooks so they are adjustable. After the transplants are under lights, I run a small fan a few hours a day. The lights are all plugged into one surge protector so I flip one switch to turn them on and off. When a shelf is not in use, I just unplug those lights.

This is not a very good picture, so you have to look closely to see the top area that I use for germination. I didn't have the light on in the room and didn't realize how dark it was going to be.

I try to keep the real heat lovers, like peppers, up high so they get the benefit of the rising heat. I don't want the tomatoes to be warm so I keep them near the bottom if possible. I am about a week away from planting.

Here is a link that might be useful: My shelf

    Bookmark   February 10, 2011 at 7:58PM
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ditnc(7 NC)

Wow, thanks everyone for so many great ideas and helpful info. I really appreciate all the responses and support!

    Bookmark   February 10, 2011 at 8:37PM
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Christmas lights! I have used christmas lights to germinate my seeds last year and it worked great. I just put them in small cups, set the christmas lights in a metal baking pan, then set the cups around the lights, put them under the grow light.

Worked great!

    Bookmark   February 11, 2011 at 3:05PM
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I prefer to use a standard 2-flat heating mat underneath the flats, until they have germinated. I have had great success with it (almost perfect germination, within 7-10 days). Then, after germination, move to whatever light/heat sourse you use.

- Steve

    Bookmark   February 13, 2011 at 4:39PM
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jollyrd(Richmond VA)

one more vote for Christmas lights -- that is the ONLY purpose I use them for. They dont get bothered with water drops.

I have them and the overhead lights pluged in a timer that runs them for 14 hrs a day - so I dont have to think

    Bookmark   February 14, 2011 at 5:32PM
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I have never used a heat mat for my tomato seeds. I cover them in plastic wrap and put them in a spare bedroom. I've always had them sprout in about a week. That room is no warmer than any other room in the house.

    Bookmark   February 14, 2011 at 9:15PM
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I like rope lights in sand. The lights heat the sand and the seed trays sit on top of it. Last year was our first time trying this system and it worked extremely well.

Here is a link that might be useful: Rope Light Heating

    Bookmark   February 14, 2011 at 10:24PM
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I used a regular old lamp. It maintained 72 degrees in the general are while the room was 68. Done three batches of seeds and they were up on the 5th day everytime.definately need to go under the shop lights soon as they poke through tho.

    Bookmark   February 15, 2011 at 11:58AM
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I planted my seeds in cups one year, and they didn't come up. Now I put the seeds on a plastic lid. I place the seeds between a folded paper towel, and keep it in the house.
When the seed first starts to sprout I plant the seeds in cups, and place them on my glassed in porch. If you don't plant the seeds when they first start to root the root will go into the paper towel, and it can break off some of the end of the root.
Works for me.

    Bookmark   February 15, 2011 at 7:06PM
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If everyone minds my asking, how have the Christmas lights worked for peppers? Is the heat only required for their germination? Like many, I have a basement around 66 degrees which worked well for my tomatoes....but I'm hoping to start peppers at home this year as well.

side note, 40 degrees in MN today...tis a teaser, but got me thinking.

    Bookmark   February 16, 2011 at 6:18PM
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I used the bottom of a plastic shelving unit with the first set of legs attached pointing up. I wrapped it in poly plastic (3mil maybe?), sealed it up except for the front which I tucked the plastic under the shelf to catch the warm air of the heating vent I placed it over. To keep the top of the plastic from falling into the plants I used wire hangers straightened, then bent into the holes of the shelving legs.
It ended up staying about 75 degrees, but you have to keep an eye on the soil moisture because of the blowing air, I had 100% germination though. Since then I removed the shelf, place the poly film on the floor with cuts made for the heating vent and use it as a fan and heater for the plants.

    Bookmark   February 22, 2011 at 4:09AM
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I have an antique baker's rack (with cast iron enameled shelves, not sure if they are a heat sink factor) sitting in the window. I don't even use the cover for the seed trays, just stick them in the window, make sure they stay moist, and forget about it. the room is 68 or higher (2 stories of windows, if it's sunny it can get to 85). I find if I cover them I can get mildew, so we go nakey. I also take every opportunity I can to take my babies outside for a field trip (I have a balcony, I put them out there and put the light on so I don't forget them!)
This way they are constantly rotated, I don't need to set up grow lights, and by the time it's plantout time, they're on the balcony all the time unless there's frost.

:) Good luck! I can't wait to smell that wet dirt smell!

    Bookmark   February 22, 2011 at 10:14AM
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