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Dahlias Planting Instructions

By Anna Aronson ; Updated September 21, 2017

The many varieties of dahlias are so vast and varied that home gardeners are likely to find one that is perfect for their garden space. The flowers, which are grown from tubers, can grow between 1 and 6 feet tall. Bloom size varies as well, with some dahlia flowers as wide as 1 foot. The brightly colored flowers are an eye-catcher and include red, orange, yellow, pink, purple and white blossoms. Dahlias are usually easy to grow as long as the right conditions are provided.

Choose a location for planting. Dahlias need full sun, so pick a site that gets between eight and 10 hours of direct or filtered sunlight a day. In areas where temperatures regularly remain above 90 degrees Fahrenheit, dahlias will do best with some afternoon shade. Dahlias also need to be planted in a well-drained soil. If your soil has poor drainage, consider making a raised bed for planting.

Till the top 4 to 6 inches of soil.

Mix 1 to 2 inches of compost in with the soil.

Dig a hole 4 to 5 inches deep. If you are planting multiple dahlia tubers, space them 12 to 18 inches apart.

Place the dahlia tuber in the hole. Tubers should be planted with the eyes pointing upward, but even if planted upside down the plant should grow.

Replace the soil surrounding the plant and pack it down firmly with your hands so no air bubbles remain.

Water the newly planted tuber thoroughly so its roots begin to form. Tubers planted in wet soil do not need to be watered. In the week after planting, it should be watered every one or two days.


Things You Will Need

  • Trowel or small shovel
  • Compost or other organic material
  • Water


  • Dahlias should be planted after the threat of frost has passed unless they will be protected from frost. Do not plant the tubers until the temperature in the top six inches of soil is more than 50 degrees Fahrenheit.
  • Dahlias can grow tall, and the blooms can be heavy, so the plants will often need to be staked for support.

About the Author


Anna Aronson began working as a journalist in 2000 and spent six years at suburban Chicago newspapers before pursuing freelance work. She enjoys writing about health care topics, in particular obstetrics, pediatrics and nutrition. She received a Bachelor of Arts in journalism from Eastern Illinois University and is now studying for a Master of Science in medicine degree to become a physician's assistant.