Is it more reddish or purplish? What have the temps been in the window? Cooler temps can make the leaves and stems take on a purplish hue. As to the yellowing....how often are you watering? I generally see it advised to let the soil dry out a bit before watering again.....overwatering can cause some yellowing of leaves. Are all of the leaves affected, or just the ones near the bottom? How large are the plants? Do you have a pic of it?

More purplish than reddish. The last week or so has been quite cool here... and since I discoved the problem, I have been leaving a window cracked for a little ventilation. The leaves near the bottom are the ones affected, though all of the leaves are affected on some of the smaller plants. I am probably guilty of overwatering. The plants range in size from 4" to 12+" tall. Thanks for any help you can give!

The purplish color is probably due to the cooler temps then...they will grow out of it when they warm up. Try letting them grow out a bit before watering and see if that helps the yellowing leaves. Mine started yellowing before I put them it the ground, but they were also becoming root bound, since you just repotted, that shouldn't be a problem with yours at this point. Now, mine are all out in the garden and looking great...

thanks, I went ahead and put mine outside yesterday with some protection. Hopefully, that will do the trick. After raising them from seed, I really want them to do well! And I know I won't be able to find starts of the same varieties in the store.