Seeds burning paper towel....?

Clarksville, TN

I am trying to germinate everything. Tomato, beans, peas, corn, strawberry, bamboo, sugarcane, dragon fruit, bell pepper, blue berry, and rasberry. Most of them will not grow roots. However, I do believe I'm killing the seed.

This is what I typically do:

Paper towel, seeds X Y & Z, water and then list what they are on a plastic zip lock bag. I put them over a light on a metal cookie sheet and wait. Typically the seeds end up having a "burn" mark on the towel. It looks like the seed was cooked maybe. I have only gotten 10 seeds to germinate this way.

I bought some rockwool 1.5 x 1.5 x 1.5. Started seeds this way. I only got a few to germinate this way. I got tomato, cucumber, and corn to sprout. However, with those I used a string of xmas lights under the seeds / trays. More sprouted...

Anyone give me an idea of what I am doing wrong. I know I have not checked the ph, however I understand that should be around 7ish with city tap water (or maybe 5) Also, on the seeds on the metal cookie sheet I have put another layer of cloth between it and the seed bag and light.

Ottawa, KS(Zone 5b)

Hello kainzow,

Welcome to Dave's Garden. Hopefully the "burn" marks are just juices that have come from the seeds. However, since the germinating temperature seems to be an uncontrolled issue, I suggest you invest in one of those thermostatically controlled heat mats. The ones that I use are the HydroFarm brand, and they are available in many sizes from several sources, including local stores. This is one source:

You can use the mat without a thermostat, but I prefer to use thermostats with mine, simply because they will prevent the mat from overheating your seedlings if they are under a humidity dome (or a Ziploc bag) and under fluorescent lights (which also supply heat). I got my thermostats several years ago, and they are the older analog style. Apparently the newer heat mat thermostats are digital, and probably more accurate.

The thermostats have a sensor bulb that you place where you want the temperature to be measured. I push the bulb into the growing medium of one of the pots in a starting tray. The Deno based paper towel method is good, but it gives you the problem of transplanting the sprouts into a growing medium without injuring the delicate roots. My zinnia seedlings grow very fast and resent root damage, so I reserve the paper towel method simply for germination tests, and germinate my seeds in a sterile growing medium in small plastic pots. Incidentally, I suggest you look into the idea of using dilute hydrogen peroxide for starting seeds. It has been discussed in several threads here in this forum, as well as elsewhere.

(not associated with any product or vendor mentioned or linked)

Galesburg, IL

First off, ignore the water pH, it is not an issue. Before you go out and spend money on a heat mat and thermostat, I would spend a little time determining what temperature ranges each of the seeds you want to germinate need. You will find that germinating on top of the refrigerator will give you plenty of warmth to germinate those needing higher temps and placing your germination bags at other places around the house will give you lower temps. Not everything needs warm temps to germinate, in fact many plants germinate with temperatures in the 55-65 degree range.

I would recommend getting a cheap digital quick read thermometer to see what your temps are and adjust accordingly.

I agree with ZM, I don't use the plastic bag method to germinate anything other than for a quick germ test. I germ way too many things to worry about transplanting from paper towels into cell packs or pots.

I wouldn't use anything metal underneath seed germination bags/pots, etc. Metal conducts heat way too fast and your problem may be overheating your seeds or wide temperature fluctuations when your lights are off.

A source I use for most of my germination/plastic pots/cell packs is the Greenhouse Megastore - They will ship products in "Hobby Pack" size in units of usually 5 or fewer (rather than by the case) and are one of the least expensive sources I have found.

Durhamville, NY(Zone 5b)

I've used Christmas lights as a source of heat but not directly under seeds. I believe you are getting them WAY too hot. If you room is 70 degrees then you only need a very little heat to warm them to 80 or 90 max.
I have found that a thermometer invaluable in gardening. I use a cooking thermometer. The kind you can buy at Walmart for $10.

This message was edited Dec 25, 2011 12:33 PM

This message was edited Dec 25, 2011 12:34 PM

Hobart, IN

Hopefully the plastic bags aren't sitting in the sun. That would really heat things up too much.

Clarksville, TN


I appreciate the responses I recieved to this (as I thought simple) question.

I do believe your correct I am cooking the seeds on the metal pan. I just picked up a thermometer to see if I am cooking them, but I feel better now than I did two weeks ago.


Corvallis, OR(Zone 8b)

Hello kainsow:
I am a month late but..
I fairly sure the burn marks you see are actually the growth of the seed coat borne fungi Fusarium spp. growing on the nutrients leaking from the seed. Since the the soils here where I live stays cool or cold and wet long into the spring this fungi kills most of my seed before they can germinate. Cool or cold temperatures really slow down germination in corn, beans and such, but wet and cold are ideal for Fusarium growth. Anyway I use a 6 - 12 hr soak in a 1.5% solution of Hydrogen Peroxide before planting. This kills the fungi and also promotes germination speed. In several species initial root growth is also promoted. Without it I get at best a 10% emergence but using it I wind up thinning out plants.
When I buy seed of high priced plants and they have a hard seed coats I use the Hydrogen Peroxide soak ( but increase the soak time to 16 - 24 Hr) to shorten the stratification period and increase the number of seed germinated.
By the way if you increase the concentration of Hydrogen Peroxide to 3% you have to limit the soak to 40 to 45 min, this kills the surface fungi and therefore usually increases total germination but does not increase the speed of germination. Also you need to wash the seed in water after the soak.

Corvallis, OR(Zone 8b)

kainzow hi again already;
One critical thing I forgot in the Hydrogen Peroxide soak. When the seed are remove and place in moist paper towel, I prefer coffee filter paper, the seed must be in darkness - no light except when you check them. Continuous light is likely to slow germination way down and in some speces reduces germination markedly.

Everett, WA(Zone 8a)

Wow, 1.5% or 3%? For spraying sick plants, I've read that 0.2% is strong enough.

So when you say "3%", do you mean straight-from-the-bottle Hydrogen Peroxide?
The kind used as a first aid antiseptic or oral rinse / debriding agent ?

I've been soaking Salvia seeds in 0.1% (1 and 1/2 teaspoons plus one cup of water). Since that is 30 times more dilute than what you're using, I guess I am not accomplisching any more than water does!

Corvallis, OR(Zone 8b)

I certainly would not spray plant foliage with a 1.5 or 3% solution, it is too strong and I am sure would do damage. With seed however I would do some testing using my favorite corn or bean seed or whatever plant for which you have lots of seed. For me the 6Hr soak with 1.5 % has been about right. I still wash the seed off before planting.
I also start a lot of the genus Geranium (Cranesbill) from seed.These plants have hard seed coats, with a few exceptions. I now soak these for 12 hr in a 1.5% solution.
And yes it is the Hydrogen Peroxide antiseptic (3 %) at the drug store in the bottle and so yes a 3% solution would be straight from the bottle. The label has it.
The seed coat for Salvia seed seems rather hard so you probably right.

Everett, WA(Zone 8a)

>> favorite corn or bean seed or whatever
>> hard seed coats,

That sounds much more reassuring than doing it to foliage or some dust-like seeds like Lobelia.

Salvia does seem to have a pretty hard coat before soaking, but they can also be fairly small seeds (not dustlike, but the large dimension less than 1 mm and the thin dimension much less than 1 mm). I might use some restraint for once and not move up to the stornger concentration until I start seeing a problem like mold.

Hmm, I wonder how many "all failed to germinate" varieties were hit by mold and I never saw it?
Maybe I should try germinating the "all failed last year" varieties on filter paper this year - some in 0.1 %, and some in 1.5% for the first 6-12 hours.

I remember some high-school biology "experiment" where we minced worms and then poured hydrogen peroxide over the pieces to show the presence of "enzymes". It foamed up like rocket fuel, so that might even have been the 32%. (Poor worms!)

Corvallis, OR(Zone 8b)

Poor worms indeed. Ha. The things we did in biology class.
I set up an experiment for a grade school biolology class last year using Hydrogen Peroxide at ( 0, 0.5, 1.0, 1.5 and 3%) 6 and 12 hr soaks. Used 2 green bean varieties and 2 sweetcorn corn varieties and then washed and planted them in a seedling mix at room temperature on the window sills. They got a bang out of it and Each student ran a 6 an 12 hr soak of one variety and solution concentration. Those that had the 3% for 6 and 12 hrs saw no germination, it did destroy the seed enzymes. Some germination occurred with 1.5% for 12 hrs. Max germination and seedling growth rate was with 1 or 1.5% soak for 6 hrs, depending on the variety.
Commercial seed of both beans and corn are remarkably non-uniform in seed quality. Some been seed I've purchased have had poor seed coats and can stand very little very little peroxide without being killed.
By the way the reason for a good washing after soaking in hydrogen peroxide is that root hairs formed early in germination are the most sensitive part of the plant to hydrogen peroxide and are killed rapidly and so the seedling dies as well.
I saw your comments elsewhere about using pine bark. It makes a lot os sence so I'm going to use that approach on high price rare seed I get. Thanks.

Everett, WA(Zone 8a)

I got my bark bark ideas from Al (Tapla) in the "Container" forum here, plus Cubits & gardenWeb.

Now that I think first about "do the roots have enoguh air"? and only seocnd about "enough water", my seeds & plants do much better.

I remind myself that "roots are like people":
you don't worry about enough food if you're dying of thirst
you don't worry about being thirsty if you don't have enough air.

First make sure a mix drains fast enough and has open spaces for air circulation

Second make sure that it retains "enough" water, or you water "often enough" that the plants don;lt wilt severly. But less water is better than too much water! Too much water means not enough air, and roots suffocate faster than plants die from wilting.

Third, fertilize just a little. Too much fertilizer makes the soil salty or too concentrated in ions, which prevents water uptake and poisons the plant. Too much fertilizer poisons and kills, whereas too little just slows growth a little.

That my new theory, anyway.

Pueblo, CO(Zone 5b)

If you look at a graph of germination versus temperature: as you increase temperature, there is a gradual increase in germination until you reach the ideal temperature. After you pass the ideal temperature, germination drops off steeply to zero. What this means is that it is better to be a little too cool than too hot - slow germination is better than no germination.
And a lightbulb under a pan under your seeds can certainly get too hot - that is the way the old kids "easy bake" ovens worked, and they got hot enough to bake a cake!

PS- If you don't have plant lights yet and money is tight - that is probably where you ought to spend your money. You can probably get your seeds warm enough by putting them in the warmest spot in the house - usually up above some appliance. Watch them closely and move them to bright light as soon as they start to sprout.

This message was edited Feb 15, 2012 6:49 AM

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