I used to set my seed pans on top of a lighted fixture and the minute I saw the first sign of germination I'd ASAP get the pans off of there and get them under the lights; the others will follow.

And when I was using those 20 row professional seed starter inserts and taking them to the seed greenhouse of a farmer friend I'd do the same thing, that is as soon as even one germinates, get them off the heat and in that case at his greenhouses it was just a matter of getting them off the concrete benches that had pipes embedded with warm water.

No reason to wait until even 50% are up as I see it. And that's as long as you know that the seeds you planted were roughly the same age. When I was working with older seeds it was a different matter and I mean seeds older than maybe 10 yo. For seed from about 5-10 yo I'd just double sow,

Carolyn

Hi, I was just about finished writing you a long responce when the power flashed out and I lost the whole thing. I see Carolyn has answered you so I'll just second her advice.

Thanks Carolyn and daylilly,

I've been focused on the temp, and am pleased to learn this new knowledge.

They are in an enclosed area maintaining the germinating temp for now, so I am assuming they should be close to the normal germinating temp. (60 something to 80 ) when I move them to what will be a different zone under the lights, for the ones still down under?

Carolyn
Don't you find that inadequate light and longer time on the heating mats also cause lankier plants?
Dennis

Why can't you give them both heat and light?

All tomato seeds are not created equal.

All tomato seeds are not planted at equal depths or in contact with equally moist or warm particles of starter medium.

My thoughts: So what if some do not come up at same time. The ones that come up first likely will express the greatest vigor. The ones that come up later, well they just come up later and I give them away or cull them out. The ones that don't come up at all, well it wasn't meant to be.

And yeah, as soon as they come up, straighten out and open their cotyledons, the trays go under bright light 16 hours minimum per day or into a hothouse environment.

Of course, I overseed my starter flats. I don't like sending out or receiving like 3 or 5 seeds and being forced to feel like a miser or seed pauper. I think seedlings should be planted en mass so you can cull and select for the most vigorous. JMO.

Appreciate the input hoosier.

I originally was wondering as Carolyn so graciously clarified was..... in order to keep a certain amount of sprouts from going wild before the rest germinated in the tray,...would it be best to get them under light and would the rest germinate allright from that point in the same tray.

Did that today w/ 1/2 dozen out of 50 in three starter trays.
I will return tommorrow to see how they did , as they are in a different temp zone, and enviornment than the main trays.

Tom

p.s. whats up with these bing words?

I don't know if ziplocks are feasible with so many seeds, but I have had excellent germination using ziplocks and damp paper towels. Last year I tried seeds that were 8 years old, from trades where I might have only 2-4 seeds, and got good germination. Where normally in peat pots or seed mix I typically got 0-4 germinations with 4 in each pot, stretching over 7-31 days, with ziplocks this year using only saved seed from last year, I had virtually 100%germination between 7-14 days and only 2 stuck seed coats out of 112 seeds. The hitch is I take the seedlings and plant individually in rose pots (2 1/4" square) so it might be hard to handle 800 seedlings. OTOH I had only 5 failures after planting so didn't waste a lot of effort on empty pots. I overstarted seeds since I wasn't sure how much germination I would get, but after seeing my results I would plant fewer next year and not waste as much time and effort.

returned to find all the rest germinated after first signs,then under the lights, just as Carolyn said.

Have to wonder why three flats did,nt show signs of germinating at the same time as rest, being they were all together at the same temp and enviornment. Will see tommorrow.

Probably seed age, position on the shelf......moisture content....seed fermenting at harvest?..........