At what temperature do seeds get destroyed?

lycomania · March 21, 2015

Hi! I recently started my seeds (tomatoes, some herbs) on a heating pad. I absent-mindedly turned it on high. I checked the temperature and it was around 110-113 degrees, probably for a day or a day and a half.

What do you think is the likelihood that I cooked them?

RayR · March 21, 2015

I'd say you cooked them good. Optimal germination temperature for tomato seed would be between 70°F-80°F. I've never cooked seed before but I would think that anything over 100°F would fry the seeds.

Rfdillon · March 21, 2015

I wouldn't start over just yet. Please give them at least 5 days to see if they sprout, but you may wish to procure new seeds if they don't come up in 7-10 days.

Fred Hempel · March 21, 2015

High Mowing uses heat to kill seed pathogens.

They use a 20-25 minute heat treatmentt at 122 degrees F

They say that 118 is a much safer temp.

110 to 113 for a day might be OK.

JamesL · March 21, 2015

If they dried out as well then Ray is probably right. Cooked. If they stayed wet then Fred and Rfdillion are probably right. How's that for a non-committal answer?

If you have the space and the extra seed I would say start some extra as a hedge. You can always give them away!

KarenO · March 21, 2015

What did you check the temp of? The potting mix or the heating pad?. I would wait, at least for the tomatoes you will know within a couple of days if any will come up. I hope they do come up for you. It is not necessary up use heat for indoor room temp germination of most seeds, better to wait a couple of extra days for room temperature germination many times than risk too high of a temp especially with a heat source that is not regulated with a thermostat. Unfortunately this is a pretty common lesson many seed starters learn the hard way. It might work out yet, let us know how it goes.
KarenO

lycomania · March 21, 2015

Thank you all for your suggestions and info. It really helps push back the panic.

Thankfully, the seeds were all nice and wet. I checked on them a while ago and the basil seeds had already sprouted. I *think* I see some activity on some of the tomato seeds so I will wait a day or two before doing another planting. I'm starting early so I have some time.

I hope you have a great season!

Stvrob · March 21, 2015

Unless your short of seed, your time is probably of more value. I would sow more seed in the same tray.

lycomania · March 23, 2015

Okay, I checked this morning and some of the tomato seeds have sprouted. Hopefully I'm going to be alright.

Karen, sorry I missed your question. I took the temperature with a thermapen inserted into the peat medium.

This is always such an exciting time of the year.

Worth1 · March 23, 2015

Quote:

Originally Posted by lycomania

Okay, I checked this morning and some of the tomato seeds have sprouted. Hopefully I'm going to be alright.

Karen, sorry I missed your question. I took the temperature with a thermapen inserted into the peat medium.

This is always such an exciting time of the year.

I figured they would some of my seeds have been in some pretty hot places over the years.
Texas for one.

Worth

lycomania · March 24, 2015

Haha Worth, that's what I was (optimistically) hoping on. They all seem to be coming up now and are under the lights. Whew! Thanks to everybody for the replies and suggestions. They made the "sweating period" that much easier to bear.

March 21, 2015	#1
lycomania Tomatovillian™ Join Date: Apr 2013 Location: Zone 5b Posts: 179	At what temperature do seeds get destroyed? Hi! I recently started my seeds (tomatoes, some herbs) on a heating pad. I absent-mindedly turned it on high. I checked the temperature and it was around 110-113 degrees, probably for a day or a day and a half. What do you think is the likelihood that I cooked them?

March 21, 2015	#6
KarenO Tomatovillian™ Join Date: Oct 2012 Location: Vancouver Island Posts: 5,931	What did you check the temp of? The potting mix or the heating pad?. I would wait, at least for the tomatoes you will know within a couple of days if any will come up. I hope they do come up for you. It is not necessary up use heat for indoor room temp germination of most seeds, better to wait a couple of extra days for room temperature germination many times than risk too high of a temp especially with a heat source that is not regulated with a thermostat. Unfortunately this is a pretty common lesson many seed starters learn the hard way. It might work out yet, let us know how it goes. KarenO Last edited by KarenO; March 21, 2015 at 11:48 PM.

March 21, 2015	#2
RayR Tomatovillian™ Join Date: Jun 2010 Location: Cheektowaga, NY Posts: 2,466	I'd say you cooked them good. Optimal germination temperature for tomato seed would be between 70°F-80°F. I've never cooked seed before but I would think that anything over 100°F would fry the seeds.

March 21, 2015	#3
Rfdillon Tomatovillian™ Join Date: Jan 2015 Location: Houston, TX Posts: 121	I wouldn't start over just yet. Please give them at least 5 days to see if they sprout, but you may wish to procure new seeds if they don't come up in 7-10 days.

March 21, 2015	#4
Fred Hempel Tomatovillian™ Join Date: Dec 2010 Location: Sunol, CA Posts: 2,723	High Mowing uses heat to kill seed pathogens. They use a 20-25 minute heat treatmentt at 122 degrees F They say that 118 is a much safer temp. 110 to 113 for a day might be OK.

March 21, 2015	#5
JamesL Tomatovillian™ Join Date: Nov 2011 Location: Long Island NY Posts: 1,992	If they dried out as well then Ray is probably right. Cooked. If they stayed wet then Fred and Rfdillion are probably right. How's that for a non-committal answer? If you have the space and the extra seed I would say start some extra as a hedge. You can always give them away!

March 21, 2015	#8
Stvrob Tomatovillian™ Join Date: Jan 2013 Location: Jacksonville, FL Posts: 1,413	Unless your short of seed, your time is probably of more value. I would sow more seed in the same tray.

March 23, 2015	#9
lycomania Tomatovillian™ Join Date: Apr 2013 Location: Zone 5b Posts: 179	Okay, I checked this morning and some of the tomato seeds have sprouted. Hopefully I'm going to be alright. Karen, sorry I missed your question. I took the temperature with a thermapen inserted into the peat medium. This is always such an exciting time of the year.

March 24, 2015	#11
lycomania Tomatovillian™ Join Date: Apr 2013 Location: Zone 5b Posts: 179	Haha Worth, that's what I was (optimistically) hoping on. They all seem to be coming up now and are under the lights. Whew! Thanks to everybody for the replies and suggestions. They made the "sweating period" that much easier to bear.