To be clear, what I meant. I was referring to was starting them from seed in those cups. Put 2 seeds BTW, so that even if one does not germinate the other one may.
That bright LED light overwintered a bunch of our plants well this winter,
But LED lights do not have the spectrum that grow lights do.
Well, I did some research. That gets to be an interesting subject.
https://growlightinfo.com/what-color-light-do-plants-grow-best-in/
If flowering is not an issue (need high red output), then it appears a good, wide & smooth spectrum "daylight" bulb should not be bad at all, and even a "white" bulb with a wide smooth spectrum might be ok.
I did already know that decent "daylight" LED's have a lot smoother spectrum than fluorescents (and I suspect those FL grow bulbs are really "spikey".)
I cannot accurately graph out the spectrum of that LED light I used to overwinter some plants this last winter: It's a Rural King special, so good luck on getting mfgr. info. on that! In any event, it did BETTER than the old 40 watt grow bulb in the same spot, possibly because it is so much brighter that there was enough of all colors the plants wanted to at least get by and stay fairly green. (The mature tomato plant was not quite as dark as it'd be in June sunlight, but a younger volunteer (about 6" tall when moved indoors) that happened to sprout in one of my wife's Malunggay tree pots is a bit further from the light and is paler. The Malunggay looks pretty good - all 3 of them do, but then they only leaf out in the spring, after having been severely pruned to bring them in. My wife's Calamansi plant looks great and even flowered rather profusely, though it produced little fruit -- I suspect it needs real tropical or at least summer conditions for that.
The upstairs room these plants overwinter in is not directly heated: It can get up to 80+ deg. F on a "warm" winter afternoon, but it can also get down to ~45 deg. F on extremely cold nights, so it's not exactly a summerlike environment. By the time I'm trying to start veggie seedlings, tho', it stays above 55 deg. F even on cool nights.
I suspect that younger tomato plant was the clue, and seedlings need more light to thrive than mature plants (generally) do to overwinter. So, I'll move my light in closer, go with bigger starter containers (modified cups), and see how that works. That (much brighter bulb and 1/3 the distance) should give nearly 10x the intensity I tried last year.
BTW, true "Grow Bulbs" based on LED's exist, but are pricey.
https://www.amazon.com/GE-Lighting-93097589-Balanced-Spectrum/dp/B07NP34CLV
To go back to Fluorescents at this point I'd need to buy fixtures and bulbs. Funds are tight, so I'd rather avoid that, too. (Cheap fixtures carp out faster than the bulbs, in my experience!)
In the meantime I have one now 5' "long" overwintered tomato plant, ready to unpot & transplant, a 1-1/2' overwintered plant ready to dig away from the Malunggay tree, 9 small purchased plants, and probably that many volunteers in the garden (likely good enough for salads and such) to start with. As soon as it quits raining!!
This should be interesting!
Now if I can get my wife to get some seeds for those Asian squash she uses in about 5 different recipes...