Knowing when to plant daylilies depends completely on the soil. If the ground is soft enough to be worked, it's time to plant daylilies. This means you can plant them in the spring, summer, or fall, although spring and fall are the preferred times. However, if you do plant in the fall, make sure you include a heavy layer of mulch to protect the young plants through the winter.
Daylilies love the sun but they will also do well in partial shade. They need at least six, and preferably more, hours of direct sun. Pastel, pink, and red daylilies prefer to have some shade or the blooms may fade. If planted in partial shade, your daylilies will turn and face toward the light.
Choose loose loamy soils for your daylilies and amend poor soils with compost, rotted leaves, wood chips, or other organic matter. Make sure the soil is deep and well-draining.
Dig a hole four to six inches deep and spread out your daylily's roots. Fill the hole with soil and tamp down gently. The topmost roots should be 1/2 inch under the surface of the soil. If you plant too deeply, the daylilies may not bloom for a year or two. Plant daylilies about 16 to 18 inches apart if you plan to divide them within 3 5o 5 years. If you are going to let them clump longer than that, plant them 24 to 30 inches apart.
Fertilize your daylilies in the spring and fall with a layer of compost or well-rotted manure. Other fertilization should not be necessary.
To get the most blooms, make sure the plants get plenty of water just before and during the blooming season.