The Stokes catalogue under Impatiens suggests covering the tray with blue plastic.
And somewhere I came across strawberry seed needing red light?

What light requirements have you come across?

Wow, that's news to me, but then again, so was growing strawberries from seed!

You should conduct a scientific experiment:
One container as directed, with the plastic color covering, the other container without the covering.

Make observations, document them, write your findings, and report them.

Caroline I found a page that touches on the subject:

http://www.gardenguides.com/13...

Essentially what it is saying is that blue light encourages leaf growth and red light encourages flowering.

Aha! Perhaps that's why I've seen recommendations for using red mulch fabric around tomatoes?

They actually sell red plastic to put around tomato bushes!

http://www.shovelandhoe.com/To...

I think Caroline's referring to color spectrum to facilitate seed germination, as opposed to overall plant growth and blooming

See "greenhouse"
http://www.stokeseeds.com/prod...

Joanne had actually posted this is in the past. It seemed to work well for me, but, it wasn't a controlled experiment. I just tried covering a flat with blue plastic


Karen

Considering seed coats, I do not think that a specific color spectrum would have any influence on seed coat cracking. Once the seed has cracked, then yes.

I had not heard of it for seed germination before.
Thanks for the comments.

I would think it would actually help with seedling growth since what you want at first is robust stems and leaves. I'm definitely going to try it on some of my seeds I'll be starting in a few weeks. I had heard of this before but never in conjunction with seedlings. I might even try the red shift to see if I can get stubborn plants to bloom sooner.

I think that it is worth a try.
If I had lots of seeds then could do the experiment.
But will try the few impatiens seeds in blue plastic.

My daughter recommended this odd colored light for growing plants indoors. https://www.amazon.com/dp/B008A698KO/

I did a little searching and came up with ScotchBlue 24 in. x 90 ft. Painter's Tape and Film that looks like it might work well especially for odd shaped containers and it's reasonably priced. It's not as dark when you unroll it.

http://www.homedepot.com/p/Sco...

Those are both good suggestions--but since I only have a few seeds---
I think that I will use one of those blue recycle bags.
If I can find an old incandescent bulb ---I'll use that for the red end for strawberry seeds.

It just occurred to me you could probably find some colored cellophane bags at the dollar stores.

Yes, I will check them out.
I get many goodies for gardening at "$1" stores.

Our recycle bags are clear blue, and we always have extras. Now there is a use for them.

If you see my photo above, the blue plastic that I used to cover the flat was the plastic bag that our newspaper is delivered in. I can't think of a store that uses blue plastic bags but there probably are some.

Also, there are cheap plastic food storage containers that have blue lids too.
http://www.glad.com/food-stora...

Karen