They look good right now. How much longer and what size cups? 10-12-16 oz.?

Dave

They are in 16oz cups. We still have 6 weeks until plant out here, so I know I will have to move them up eventually, I was just hoping they could wait another week or two until I could get the lettuce into the coldframe so everything could still fit under the lights

They could stay there a bit longer if needed. For dwarf I would transplant them about now, since they don't get tall like regular indeterminate variety. I have grown regular ones up to 8-10" in those cups. But the easiest way to find out is to check the root zone in the bottom, although I would say at that size they are not root bound yet.

Probably ok for another week but like Max said just slide one out of the cup and look at the roots. If they are already locking up all the soil in the cups and you can see roots beginning to circle around on the surface of the sides then they need to be transplanted.

If it is another 6 weeks before they can go to the garden then they were clearly started way too early. Something to keep in mind next year.

Dave

I usually start my seeds 6 weeks out.

i just recently transplanted mine into 6" pots and they were very close to the size of yours in the same size cups.. definitely transplant soon, in my opinion, they are already very close being root bound.

usually what starts to happen if you wait too long is they will start flowering and will start growing tall and thin rather than staying short and bushy.

Thanks for all the advice! I'll pop one out of the cup tonight and check the roots. I started seeds too late last year, so I ended up buying seedlings. I guess I went too far the other direction this year!

In those sized cups, with warm temperatures (70-80F), plan on plantout in 4-6 weeks. They're actually probably starting to be root-bound right now in those cups and, if I were you, I'd move up to a much larger containers, and ideally take off the heat. 60F temps will slow them down, and buy you some time, at no cost to the plants.

You could also plant out and protect, depending on how much protection you anticipate needing. Protection is pretty easy when they're small like that.

I second : They look fine now. Maybe for another week or 10 days will be fine in the cups. I would pot them up to 1/4 gallon (32 oz) pots IF they have to wait 6 more weeks.

The real issue IMO is that it's very difficult to get enough light to larger plants once they get past a certain size. You can pot up to larger containers to try to keep them from getting rootbound, but indoor lights only really get the top leaves enough light. So the plants end up leggy and spindly and unhappy.

Oh, sorry--I just realized those are dwarfs. Many dwarfs are pretty slow-growing. Even so, 6 weeks is a long time. Maybe you could pot up, then put them out under protection in 3 weeks?

Yes dwarfs are slow growers and should hold well in your cups for a few weeks no problem. Mine are much more squat/short. If you can keep them in cool temps it will slow the growth a bit. 55-65. My grow room is steady 62. (cold treatment)

Bottom water is good but let them dry out. Hopefully the water they are sitting in is just for 5-10 minutes until the cups feel weighty. Should not sit in water for long. Drying out means the cup is weightless but plants are not droopy.

They can go a bit closer to your lights. But they look very healthy!

You can pinch off the cotyledons, the lower leaves they no longer need, and top off your pots with more soil. I feed sparingly 1/4 strength every other watering and tbsp epsom salts in gal of water the other watering.