Here is how I grow dahlias in my rooftop container garden!, Ive used this method for 4 years now and will continue doing it until it stops working , I plant my dahlias in April even though it wont White Ridges Ceramic Planter, 4" Terrain Best Plants for Open and Closed Terrariums Tropical Glass Amazon.com : Miracle Gro 3 Pack Potting Soil Mix for Container Plants, Flowers, Vegetables, Shrubs, Annuals, and Perennials, Feeds for Up to 6 Months, 2 Cu Ft : Patio, Lawn & Garden