Dahlias are the mascot of the Growing Kindness Project™ for many reasons, including the incredible way their tubers multiply each year. Each year, Growing Kindness Ambassadors are given a garden of dahlia tubers to grow. Each fall, they dig, divide and share these tubers, paying forward the opportunity to grow and give away flowers. Perhaps you’ve been gifted tubers. We’re here to help you grow them! Below, you’ll find a simple guide to planting, tending and harvesting dahlias.
After you’ve purchased dahlia tubers, open the bag and store your tubers in a cool, dry place until you are ready to plant. (A basement or unheated garage is a great place.)
*Choose the best growing site: dahlias require at least 8 hours of sun each day and well- drained soil.
To become part of The Growing Kindness™ team or for more resources click here.
Prepare your soil by tilling or digging. Dahlias prefer rich soil. Add compost and a balanced organic fertilizer. Dahlias are a “hungry” plant: adding a small handful of bonemeal to the bottom of each whole will help them get a strong start.
*Wait until your Last Frost Date has passed before planting your tubers. As a rule of thumb, the ideal time to plant dahlias is when the lilacs are blooming. (The soil is warm and less saturated at this time.)
*Plant dahlias 12-18 inches apart and 3-4 inches deep with the tuber laying on its side and the eye (sprout) facing up. (If you can’t see the eye , no worries...it will find its way up!)
*DO NOT water your dahlias until the first green sprouts emerge. (Over-watering can cause your tubers to rot before they can grow.) Begin watering once leaves emerge. Water thoroughly every 2-3 days, or as needed based on your soil and precipitation.
*When your plants are 12-18 inches tall, give them a “hard pinch”, cutting out 4-6 inches of the main shoot. This will encourage your dahlias to put on more and taller stems. *Dahlias grow between 3 and 5 feet tall: be sure to provide support for each plant. Each plant can be individually staked or you can “coral” several plants by staking around a row or group of plants and wrapping the group with three rows of twine (just like a coral!).
*Manage pests. Sluggo Plus is a great organic option to help manage slugs and earwigs. To combat aphids, spray them with a mixture of soap and water. (One capful dishsoap to one bottle of water.)
*Harvest the blooms when petals are about 3⁄4ths open but before the petals on the back of the bloom have begun to fade or shrivel. The more stems you cut, the more your dahlias will bloom! It’s best to cut early in the morning or later in the evening when it’s cool. Place blooms directly in cool water and enjoy!