How to Care for Dahlia Plants in a Container
- 1). Choose a container that is a minimum of 12 inches in height and width for each tuber being grown.
- 2). Mix 1-part sterile potting soil with 2-parts organic garden soil. Fill the planting container half full and place the tuber horizontally in the soil with the eyes facing up. Cover the tuber with 4 to 6 inches of soil mixture and gently pack in place.
- 3). Water the pot lightly to dampen the soil. Over-watering the soil and tuber will increase the chance of tuber rot during the initial growing period.
- 4). Place the dahlia pot in a location that receives morning sun and is shaded from the hot afternoon sun.
- 5). Fertilize the dahlia plant with a low-nitrogen fertilizer once it reaches 12 inches in height. Repeat the fertilizer 1 month later. Do not fertilize the plant in the fall season.
- 6). Increase the watering amount to keep the soil moist at all times during the growing season as the tubers produce shallow roots and dry out quickly.
- 7). Dig up the dahlia tubers 2 weeks after the first killing frost in the fall season. Cut the stem to 6 inches in length and gently remove the tubers. Remove dirt from the root and air-dry the tuber for 24 hours.
- 8). Winter store the tubers in a container of peat moss that is placed in a cool, dry location with a temperature of 40 to 50 degrees Fahrenheit. Monitor the tubers through the storage period to make sure they are not too warm or damp.