I germinated several different coleus varieties a little over a month ago (March 10th) and here they are today (pics attached). They seem a little leggy, but I at least managed not to kill them from damping off, like so many of my others over the years. I rotate the trays daily so they don't lean to one side toward the window. (I wish I had a better light source.)
I'm wondering if these are too small to begin transplanting? Or have i waited too long? I don't want to wait until the roots are so tangled that I kill them, but I also don't want to disturb them prematurely. I'm thinking about going from these into trays of 12. Once they get a little larger, I'll harden them off and they'll go outside. I wish I had started a few months earlier than I did... had no idea it would take this long to get seeds going. Luckily, where I live coleus will thrive outside well into November, so I will hopefully get to enjoy them for a decent amount of time.
So, what should I do? Pot 'em up now, or just let 'em hang out for a little longer?
I wouldn't transplant anything without a set of secondary leaves. Primary leaves are not enough. If it's warm, I'd take the trays outside for a couple of hours during the day and bring them in at night. They'll probably be happy for some time outside. They need more light. A fluorescent would do. Closer and for more hours. If you do take them outside, don't leave them in strong sunlight. Full sun would be too much for them. Light shade will do just fine.
I doubt they have strong enough root systems to be planted anywhere. If you can put them under a fluorescent lamp, don't make it more that 20 inches away. I'm sure you'll see improvement. What are your daytime temps like?
Well, you have confirmed my fears. I guess window light is just not enough for these guys. I don't have a grow light yet, so will have to resort to placing them outside. I'm in Northwest Florida, so temps are okay here... if anything, I'm scared it's already TOO warm. I'll pick a nice shady area and see what happens.
Luckily, I ordered a few coleus from Rosy Dawn Gardens that ship this week, so I won't be relying on just these sad little seedlings for my coleus fix!
Do you think these are too leggy to recover before summer?
I don't think they are two leggy. Coleus are sort of miracle plants. As long as they have secondary leaves and are stronger, you can pinch the tip. At the leaf axils you will get new growth. Pinching is important for coleus. Any time you see a spike of blooms or even a promise of a spike for flowers. pinch it off. Allowing coleus to bloom will age the plant. Don't let is go to seed unless you need the seeds. Once you pinch off a shoot, you will see that the plant grows stronger.
I have never grown from seed. Instead it is easy to buy a small plant a take cuttings. They root easily and can go into fresh soil as soon as they have roots. I have rooted them in water, in perlite or vermiculite and water or even just potting soil. When I root in potting soil, I start out by keeping it quite moist and putting a (clear) plastic bag over its head for a greenhouse effect. As soon as it grows a bit, remove the plastic bag. I am assuming you will be putting them into pots. You can mix and match. I think if I were you, I'd wait for another set of leaves, then pinch, let them grow more leaves and then transplant. If you are uneasy about it. Only do a few to start out. It will get easier. If you think they are too leggy, trim them down. by then you will have figured it out.
Personally I try to be careful with coleus. In the shade of a tree, there was insect damage as a result of the sap. So I moved them to the north side of the house which gets lets sun and more indirect light.
By the way, you don't need a grow light. A plain old fluorescent shop light on for several hours a day works well for shade plants.
I have planted coleus from seed before and they are tougher than you would think. Even if the plant is a little leggy now, don't worry too much. It is plenty warm now to set them in the shade and harden them off. As they get more light they will get less leggy, and even if they are leggy when you transplant them you can bury them deep when you plant them. If you let the plants get much larger than they are now the roots should not be much of a problem, just wash the soil off and untangle the roots. You do have to be very careful handling them because the steams break so easily, I dropped a few of mine last year when untangling the roots. Just be careful not to let them overheat in the Florida sun, make sure if you put them in the shade that spot will stay shaded. What varieties did you plant? I never got around to planting any from seed so far, glad I saw this, I need to get some planted.