While daylilies can withstand drought because of their fleshy roots, I find it amazing the difference I get when they get all the water they need. So give plenty of water, at least 1 inch a week. Do not overwater, however, as daylilies do not like to have their roots immersed in water for extended periods of time. Give the soil a chance to drain well before you water again. You may also want to check out my hidden pot trick page for a tip on how to help ensure even watering.
Fertilizer is important for healthy daylilies.
Proper feeding will result in more and larger blooms and the plants will be more vigorous. A few varieties showed very little increase, but the majority increased significantly. The biggest increase was almost 2.5t times the number of blooms as the previous year. I recommend that daylilies be fertilized at least twice a year, once in the early spring when the daylilies begin their spring growth, and again at the end of the summer. Here in the south, where we have a long growing season, I also recommend an additional application a couple of weeks after the peak bloom season.