Whoa! Somewhere you read some misleading advice. First of all, Calendula officinalis is more of a cool climate plant than a warm climate one. In the Rogue Valley, they are usually planted (in a greenhouse or other shelter) in summer for fall and winter bloom. Second, they should be kept evenly moist. This implies light watering on a regular basis and planting in well-draining soils.Third, Karen Jennings of Park Seeds, in her book, Success with Seed. suggests that moderate fertilizer helps strong growth: seedlings should grow to flowering size in 6 to 9 weeks.Calendulas are annuals. As much as you do not want to lose these plants, we think they may have matured to a point that  further growth and even flowering  are no longer possible. Sometimes, when we leave seedlings in  a pot too long and they don't grow, they somehow harden off and "give up", You might want to experiment with planting some new seeds (usually should be done by mid-August, but still okay if you hurry) and raise the seedlings in the house in a well-lit, but 68 to 70 degree temperature. Nighttime temps should be in the lower 40's--sometimes a sheltered porch can provide for this until frost sets in. We're sorry this has happened, but "disasters" are part of learning how to garden. Thanks for checking in with Ask an Expert.