Green moss in seed tray?

[manfisher]

My seed trays are growing some green moss around my seedlings. Is that the fertilizer or is that moss? If the latter, what should I do?

 

[ChinaVoodoo]

I would water less. Those roots are probably 1/2" to 1" long, so the surface doesn't have to be wet.

I have also added a very thin layer of peat moss at this point just to smother the algae.

 

[LeftyRighty]

For over a decade now, I've sprinkled a bit of fine sphagnum moss over the top my potting soil, even before adding the tobacco seeds. Prevents mold, algae, damping-off, etc.
I assume this will work ever if seeds have already sprouted.
NOTE: sphagnum moss is not the same thing as peat moss