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germination test - too hot?

Posted by liz_h 7/8 DFW Texas (My Page) on
Wed, Jul 30, 08 at 15:48

Awhile back, I took about 20 packs of old seeds and decided to test for germination before I tossed them. I used the paper towel method. Not having a heating pad handy, I decided to leave them in the oven overnight with the light on. Unfortunately, the oven air temp was either 105F or 115F the next morning. (I forget which.) I figured I'd cooked my seeds, but left them on the counter for a couple of weeks anyway. Last night I decided to toss them, but did one last check first. I had good germination from 4 tomato varieties and Chinese mustard, no results from anything else.

So now I don't know for sure if the other seeds were ruined in my test or weren't viable to begin with. The seeds were various vegetables & herbs, from 4 to 10 years old.

Follow-Up Postings:

RE: germination test - too hot?

I would say most were too old. I had many old veggie seeds, and some flower seed (only 1 variety of flowers germinated) I tried to germinate this year and they didn't do anything. I had good results with tomato seed though, they are tough!

I had good luck with 5 year old basil, catnip, and catmint. Although, germination rate was no where near as good as it would have been with newer seeds.
When did you do this? If is was warm outside why didn't you just place them in a semi-shaded area instead of placing them in the oven?
That seems awful hot, but they survive in the ground when it is heated too, and I am sure it is hotter then that temp at times.
My results were anything older then 5 years old were just too old to germinate. I had seeds from 2000 up to 2005. Of course the 2005 and newer did much better, I acutally got plants (veggies) out of some of them.

I hope I helped you,
:) Fran

RE: germination test - too hot?

Decades ago in a lab I briefly had access to a "growth chamber" where one could test conditions such as humidity, CO2, oxygen, temperature and light. It even had a vibrator.

Most seed seemed to me to germinate better at temperatures a little bit better than published. The trick seems to be to get them to get them out of the germination test and into growing conditions quickly. I didn't do much with seed because my space and time were supposed to be devoted to rooting.

RE: germination test - too hot?

  • Posted by liz_h 7/8 DFW Texas (My Page) on
    Mon, Aug 4, 08 at 16:10

Thank you, that did help. :)

Fran, I started these seeds in early July, when it was quite hot outside. It just didn't occur to me to set them outside! I'll toss the seed packets that didn't make it, but keep the ones that were somewhat viable. I'll try them next spring.

In the past I've started seeds in peat pellets, but I think that with these I'll use the baggie method described in the FAQ. That way I should get some viable plants even at very low germination rates.

RE: germination test - too hot?

I love the "baggy" method, we've done it more or less that way for years, when I was a kid...we used to sprout bean seeds and such on a paper/styrofaom plate with a little water and then a moisten paper towel over type, they would sprout.

I have used coffee filters for about 8 years now, I like them better and they are cheaper than paper towels too. Much stronger than paper towels. Oh, make sure you keep notes on what you do, how you start them, how long it took them to germinate, germination rate, and so forth. That way you will know how long it takes for your climate/temp. you had at that time.
Like now, I have seeds going in an unair conditioned room, ave, day temps 96 night about 70. I have Mexican Bird of Paradise, they germinated in 1 day. 100% too. Carnations took 2 days to start, they average in the soil 14-21 days.
So, this is really the best way, unless you start them outdoors, winter sowing and summer/fall sowings.

Anyway, if you would like to chat about anything, email me, let me know in the subject you are the one from the TEST Post...
:) Fran


I have lots of unopened packets of seeds sitting around in a drwaer. Most are dated 2005 , some go back to 2002.Are they likely to geminate or should i just put them on the compost heap? I have wallflowers, geranium seeds, parsley ,cress , radishes, verbena,dill coriander, chrsanthemum, tagets, naaturtiums , oh and some tomato.
Advice on how to germinate seeds from the packet would be very helpful too? Many thanks, Andrew

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