Last spring, I grew out a variety that was getting a little long in the tooth, and also shared a few seeds.

It was embarassing to report to the gardener that asked that I was experiencing really poor germination. I chalked it up to ancient seeds.

Of 40 seeds planted, I eventually got 5 tomatoes, planted all, and saved seeds from three...one grown in a homemade earth box, and two grown a distance away from cross-pollination danger.

On November 17, I placed 25 seeds on a damp towel, in a container to prevent evaporation. By Dec 2, nothing. I tried again. Two weeks and nothing. Temp about 70°.

I gave up, and put the containers aside while I used the space to check others. Basically on a shelf in my basement seed room, forgotten.

Tonight I remembered: the November seeds have sprouted 6 of 25, the December 8/25. While still poor, apparently they wanted to experience cooler conditions.

Has anyone experienced anything like this?

Actually yes, this season most tomatoes germinated around the same time, however some did not -a mix of own saved and commercial seed. Seed tray was left on bench after potting those germinated and came back from holidays to find most of those that had missed were up. Plants have grown well considering season here

Germination issues that I've noted with fresh seeds were not, afaik, related to temperature for sprouting but were evidently caused by my allowing the seeds to dry out too much over the winter. The relative humidity in my house is really high in the fall, because windows have been open all summer and the central heating isn't turned on until it gets really cold. But during the winter, relative humidity drops very low - apparently lower than the optimal for seeds. My usual practice has been to keep the fresh seeds in paper until the heat gets turned on, just to make sure I don't pack them up with too much moisture. A couple of weeks into the heating season, I pack them into ziplocks for long term storage. I haven't had any issue with seeds I packed up this way, and seem as fresh as ever with 100% germination or close, even after 8 or 9 years.
One year I left the seeds in paper packets and didn't put them away. I was sadly surprised the following spring, to see that germination was way down from what I expected.

I do think it's possible to overheat seeds during germination, but that is because of my old heat mat being uneven. You notice that germination follows the physical pattern and not related to variety. If seeds of unknown freshness or source don't germinate, I've wondered or suspected the heat mat might be the culprit.

My experiences with germinating fresh seed is that I get about 45% germination in 3 days, 45% germination in 4 days, few in the 5th and 6th day, and close to the remaining 10% on the 7th day. If my thermometer is accurate, this is done at about 73 degrees. There are no improvements by going to a higher temp.

At 70 degrees, I get less than 10 percent germination in 3 or 4 days, as most take 6 to 10 days.

PM me your mailing address, as Orange Russian/Doukhobors has your name on it.

I had something really strange happen years ago, with some Maui Purple pepper seeds that didn't sprout at all, in the spring. I usually sprout my peppers in a tray, with strips of vermiculite, which I kept on my griddle on the range, with pilot lights under it, making a very good "heat mat"! Plus, it was where I would see it all the time, and see the new sprouts; occasionally I haven't had some germinate - no big deal, as I usually had more than 20 varieties, and I'd just take a sprout of a similar variety, and put that in the pot, so none would be left empty. When all the pots are filled, and the peppers are growing well, I pull the extra seedlings out of the vermiculite, and let that dry out, and dump it in a bag, or bucket in the shed, to use in something later. Here's a photo of the vermiculite strips:
Peppers sprouting in strips of vermiculite, almost finished on 4-20 by pepperhead212, on Flickr

Late that summer, I made some starting mix for the fall crop, and added some of that vermiculite, as well as the usual things. I didn't put those trays of pots on heat mats, as they were cold weather crops - lettuce and brassicas, mostly. A few popped up quickly, as always, and in 5 or 6 days, all were up, but there were some weird ones, with elongated leaves, like peppers, not like the rounded, early leaves of the ones I planted, which came up in the same pots. And after several days, the leaves started turning purple, and that's when I realized they were those Maui Purple seeds! They wouldn't sprout in 90° vermiculite, back in the spring, then that sat in the shed all summer, often getting so hot that I usually have to air it out, before touching metal objects, and the like! Then the seeds sprouted quickly when I had it in the unheated mix, with the fall mix. I couldn't grow those in the fall (and I don't grow peppers indoors), but I figured I'd try more of those seeds (and I still have a bunch of them left), and maybe "treat" them, the same way - moisten them, in warmth, then dry, even warmer, then try to sprout them at room temp. Didn't work, but I've only tried it once, and I'll keep trying, as it is a very unique pepper - purple flowers, with almost black leaves and peppers, ripening to a bright red. Not the best pepper to cook with - a little bitter, and too hot, for most, but definitely the best purple variety I've found.

I'm guessing my original saved seeds experienced some sort of genetic problem...one that was continued in the seeds I saved for this year. As I recall, the seeds that eventually sprouted last year took a month, too. I use a method similar to Craig LeHoullier's; each cell of a 4-pack contains 2-6 or so seeds, and when they begin to crowd each other get pricked out. It was easy enough to just keep them warm and barely moist.

But when I didn't see anything in a week, I planted again. At transplant time, the "babies" were a bit young, but they caught up.

There are several things that come to mind, that could be a genetic cause. One is the germination inhibitors which for tomatoes are present in the gel. But maybe a mutation could cause those inhibitors to be produced in the seed coat as well. It would delay but not prevent germination.
Another genetic possibility is the hardness of the seed and apical pore. If a mutation caused a thickening of the walls around that apical pore, it might delay the seed from sprouting because it takes longer to break down. (Similar to what I think happens environmentally when the apical pore is hardened by getting very dry, or after being dry for a long time, in old seeds.)
Traits that delay germination could be favorable, for example, in a spring freeze and thaw type environment, where the seedling that sprouts quickly at the first opportunity might be killed by the following freeze.

Thank you, Bower.

I had planned to offer this variety in the MMM swap this year, but don't want to share seeds with gardeners that will frustrate them. I'm still deciding, but am pleased that I WILL be able to grow again at the very least.

Old thread but new info.

I sent Gary (4M swap) a few packets of Martin's Super Roma, originally from Martin Longseth (Paquebot) around 20 years ago from Gardenweb.

I reported that germination was very low, and took forever as per germination testing. I'm going to say still a bit low @75%, but pic at 5 days at 72°-75° If anyone received these and started them early, I apologize: you'll have to baby them along.

eyolf wrote: ↑Sat Mar 04, 2023 12:38 pm Old thread but new info.

I sent Gary (4M swap) a few packets of Martin's Super Roma, originally from Martin Longseth (Paquebot) around 20 years ago from Gardenweb.

I reported that germination was very low, and took forever as per germination testing. I'm going to say still a bit low @75%, but pic at 5 days at 72°-75°
IMG_20230303_210404821_HDR.jpg
If anyone received these and started them early, I apologize: you'll have to baby them along.

That's the temp range that I like with fresh seeds.

I think all of your labels say that it may take about a month to germinate. I have a few more participants to send out seeds. Should I cut off that part of the label?

I started germinating pepper in a styrofoam egg incubator at about 75% humidity and around 36°C. Everything is usually up in a few days. I keep them in there a few weeks until they're ready to be potted up. The incubator has Plexiglas windows so growlights work OK. Even in those conditions I still have a few varieties that take more than a week to come up. Soaking the seed first helps too, especially with older seed.

Tomato seeds are treated similarly but humidity is about 60% and temperature is about 27°C.

I tested some older tomato seeds today. Still a month too early for me to start tomatoes, but what I did was set 9 old varieties to soak, only about 4 hrs, and later I'll put those on the PT in the petri dishes, and set the plate on the back of my griddle, on top of the molcajete, where the temp is a fairly constant 80°. I wanted to check those old seeds to see how they germinate - most I had plenty of, so I used a generous amount of them, but one I only tried 2, and another only 3, since I didn't have many of those. I'll see if any need to be replaced. No old peppers I had to test.

Tormato wrote: ↑Sat Mar 04, 2023 9:24 pm

eyolf wrote: ↑Sat Mar 04, 2023 12:38 pm Old thread but new info.

I sent Gary (4M swap) a few packets of Martin's Super Roma, originally from Martin Longseth (Paquebot) around 20 years ago from Gardenweb.

I reported that germination was very low, and took forever as per germination testing. I'm going to say still a bit low @75%, but pic at 5 days at 72°-75°
IMG_20230303_210404821_HDR.jpg
If anyone received these and started them early, I apologize: you'll have to baby them along.

That's the temp range that I like with fresh seeds.

I think all of your labels say that it may take about a month to germinate. I have a few more participants to send out seeds. Should I cut off that part of the label?

Apologies for being late.
If there are any left, perhaps deleting that would be wise.
I can just slow my babies down with cool temps and barely enough water.