I have GROWN ( pun intended) to fall in love with Coleus....and after years of rooting and transplanting cuttings and buying plants I've decided to study up, collect and dry many many seedlings and throw my hat into Amateur Home Greenhouse propagation .
Perhaps I've gone overboard here on the East Coast of NJ..but I have started quite a large collection of different Coleus and SO FAR successfully getting a pretty high percentage of seed germinations.
So I'm at the point now where I'm in need of some guidance..... At this point do I move on to separating and transplanting these small seedlings into the next level of foam cups??? Or should I wait a few more weeks???
I have a five shelf greenhouse with a HYDROPONIC Advanced Spectrum LED grow light AND I have a huge front bay window which gets great direct & indirect sunlight all day which I plan eventually to have shelving to hold all these plants until I plant outdoors as well as sell them & give them away to friends. Thanks!!! Any guidance is appreciated

First to ATP ,
not sure I am the best one to give advice this is only my 2nd year planting seeds of any kinds not just coleus , but I have read after the first or second set of true leaves (not counting the first set of germination leaves) it is ok to transplant. Personally I just usually play it ear , if they are overcrowding or I think they need a deeper container , I usually dig young seedlings out gently with a plastic spoon , place them in a plastic or glass dish and gently mist off any dirt with a misting squirt bottle ,
gently separate tangled seedlings with ( I use a bobby pin ) but any small tweezers or instrument , poke a big enough hole in the moist soil of new container / pot / cup for the new seedling and place it in , once you are happy with it's placement , gently push in surrounding soil until you are happy that it is supported firmly enough and lastly maybe a final misting squirt or two to seal the deal.

Good advice.. can always separate some.. and leave some.. always good to experiment and leave some alone for backup. . I have had some seedlings in a foil loaf pan for months.. jammed up.. sometimes I just took cuttings off those .. and just planted the whole tray out in spring

Thanks for the helpful advice!! I have enough seedlings and rootings to experiment with. Its great to have this Forum to fall back on if needed. I transplanted more seedlings today. The trays I have are really coming along nicely!!!

LovetheseBuggers said:Thanks for the helpful advice!! I have enough seedlings and rootings to experiment with. Its great to have this Forum to fall back on if needed. I transplanted more seedlings today.

The traditional advice regarding transplanting seedlings is intended for a situation where you are plucking seedlings from a rather thickly-sown, mass-planted flat, and in doing so, disturbing the roots. It was good advice, but originated years before the various grow-cube solutions were invented.
When using grow-cubes you're not so much "transplanting" as you are "potting-on", which gives you a lot more flexibility. You can let them sit a little longer if you like, since they're a lot less likely to become seriously root-entangled with their neighbors. It's probably better to let them get a little larger, so that they have a well-established root system when being moved up to the next larger pot.