Hi Tom,
I use a soilless mix called promix bc, you can get it from your local nursery. I transplant them into miracle grow moisture control potting soil and some perilite to keep it loose for the roots. The soil you grow your daylilies in is extremely important. I have about 8" of a 50% compost 50% topsoil mix for my daylilies. Fertilizer and macros are important too. Check out the forum for older posts about soils and fertilizer. I will add a new post for soils. There is an article about fertilizer. Have a great day...