After cold stratifying in the fridge, I started Aster macrophyllus (native big leaf aster) and Eupatorium coelestinum (native mistflower) in pots on 3/29/12. Well, they germinated at 100%, but are growing incredibly slowly! The largest one of each is maybe 1 and 1/2" tall - about 2 sets of true leaves. Is this normal? At this rate, I'm not sure I can even set them out this year!
I am not familiar with those particular plants, but no one is replying to your query?
Are they in good soil? how much light do they get?
Sometimes plants just grow slowly.
Has it been very warm there?
Many plants slow down with summer heat,
and then pick up when cooler weather comes back?
Thanks, Caroline. They're in seed starting soil in a south facing window under fluorescent lights. It's fairly warm in the room as we keep the vent closed. I may water with a very weak fish emulsion solution to jump start them a bit. They look healthy, so I'll just wait!
Cooler temps and some fertilizer will get them growing. As hot as it has been, seedlings are not growing much. You have to remember that plants generally like cooler root temps. I always have problems with seedlings this time of year because the root temps are so high. If I keep any in pots that are still too small to transplant I will move them outside in mostly shade and dig a hole to bury the pots. I'll grow them in the pots/ground to keep roots cool until ready to transplant. You will always have some roots that will grow through the pots, but if you dig them up instead of just pull the pots out of the ground you can save most of them (but not always save the pots if you have to cut them to release the roots).
Thank you, TRC65. They're actually still in the house, but they're in a room where I have the vent closed so they don't get the direct air conditioning. Maybe I'll open the vent in there to get them going, then in September start hardening them off.