Hi stir_fryi,

" Should I thin each pod to one stem per pod at this point? "

Yes, provided that these are just commercial zinnia seeds. Or you could wait until they put out a pair of "true leaves" and then keep only the best looking plant. To avoid disturbing the roots of the "survivor", use small scissors to snip off the cull at the ground surface.

" I have them under an LED plant light 14 hours per day. Light is about 9" away from top of seedlings. Is this a good height? "

Apparently not, since your top picture shows your zinnia seedlings stretching badly for light. Keep the light much closer to the plants, as close as you can without actual contact. I would shoot for 2 inches above. Also, increase the exposure time significantly. In order to try to get a handle on this stretching problem, I would go for 6 hours of dark and 18 hours of light.

If you have a small fan to blow on them to give them a gentle wind and some "exercise" that should strengthen their stems.

There is a potential problem with your LED light. The top picture seedlings seem to be leaning to the left. That leaning tendency may become more serious as you lower the light. All of your seedlings may grow toward the light or even the individual LEDs in the light, which will cause extreme leaning in the seedlings farthest from the LEDs. You may need to add a second or even a third LED light to get more even light distribution.

I started my indoor zinnia growing in 2004, at which time the most affordable plant lights were 4-foot 2-bulb T8 fluorescent shoplights. At that time Home Depot was selling a 2-bulb T8 shoplight without the bulbs for about $6. The price has more than doubled since. I mounted 3 or 4 shoplights over a 2' x 4' wire frame shelf to approximate an area light source from 6 or 8 tubes. I used (and still use) a mix of 3400K and 6500K T8 fluorescent tubes to provide red spectrum and blue spectrum light, which also had enough green component to look like daylight for my viewing and photo taking pleasure. A box of 10 tubes cost about $16 at Home Depot at that time. Prices higher now.

I don't deny that LED lighting is the "wave of the future". But it is questionably cost-effective at the present time. And I know that the plants like that magenta-purple light, and reflect green light because they don't want it. But when I finally convert to LEDs, I will insist on the inclusion of some green LEDs to produce a nice white light. In the meantime I will get it from T8 fluorescents.

ZM

From my experience, if you are simply growing the zinnias to plant outside, all you need are shoplights with bright white tubes (6500K), you don't need a warm and a cool because you just want the plant to grow to a decent size; they don't need to be flowering inside. Looking at the results from your LED setup, I would say that's not an ideal outcome, they look stressed. Next consideration is growing them in the right soil...I've been using Promix for the last couple of years and my starts have been the best ever. It took a number of years of experimenting to find out what works, now there's only the problem with running out of shelf space under the lights.

So my coworker who does this every year doesn't even use any artificial light, but still has success.

I have brought the tray up from the dark basement and put it in a room near a western exposure window. Still using the LED light. I hope that will help as it is the best I can do right now. I have limited spots to put it do to a curious cat!

I am also running the fan and will turn the tray regularly.

You could thin out,bit don;t pull just cut off at the base.

So my coworker who does this every year doesn't even use any artificial light, but still has success.

==>>> my neighbor just plants them outdoors .. when the soil warms ... i hope you saved some seed to try the easy way ... or go buy another pack ...

i never had much luck with peat pellets ... that might be the next thing to go.. as your experience level increases ...

when i used a light stand.. it was a shoplight fixture with plain old florescents .. kept 2 inches from the plants .. on 16 hours.. off 8.. with one on/off cycle in the middle of the off 8 hours.... someone once told me.. it confuses the plant into thinking the lights are on 24 hours ... who knows ...

if you cant move the lights down.. move the trays up ... put something under them ...

presuming you arent doing this on zens level... i dont know why you cant leave two plants per pot ... might turn out interesting ... try it with a couple.. see what happens.. learn ... i remember my own experiments.. more than i remember what others tell me.. or i read somewhere ...

ken

Thanks for all the info. I'd say my mistakes so far were not getting them light immediately after sprouting, putting them in the basement under the light (where it is otherwise dark), and having the light way to high initially.

Next question -- do you think I should dump this try and start over? It's just a $10 mistake at this point and the loss of 10 days...

Hi Stir Fry,

" ...do you think I should dump this try and start over? It's just a $10 mistake at this point and the loss of 10 days... "

It depends on how your seedlings are doing at this time. Could you post a picture of the present seedling situation?

ZM

Not much has changed other than I thinned them. At best they are 1 1/2" tall, at worst 3". I just don't want to wait weeks and find they never set "true" leaves. BTW -- those are green onions on the left (ran out of zinniea seeds!).