What You Will Need
Top quality dahlia tubers
- Organic fertilizer
- 4ft t-posts
- Drip irrigation or soaker hoses.
- Dahlias require full sun (at least 8 hours daily) to thrive and bloom abundantly. Southern growers might need to provide plants with afternoon shade if summer temperatures are extreme. Dahlias are cold sensitive and should not be planted until the soil has warmed to above 60* and all danger of frost has past. Check with your local county extension office to find out the date of your last spring frost.
- Select a sunny garden spot with freely draining soil and prepare it thoroughly before planting. Amend beds with 2-4 inches of high quality compost or well rotted manure, a light dusting of bone meal and a balanced organic fertilizer. Mix all ingredients into the soil to distribute evenly.
- To plant, dig a hole 4-6 inches deep and place the tuber on its side, horizontally with the growing eye facing up. Once in place, refill the hole with soil. Dahlias get quite large, so allow at least 12-18 inches of space between plants.
- Dahlias require consistent water throughout the growing season, so install soaker hoses or drip irrigation while they are still young. Dahlias should not be watered until you see the first green shoots poking through the ground. Overwatering before shoots are visible can lead to tuber rot. After plants reach a foot tall, give them a hard pinch by snipping out 3-4 inches of the growing center to encourage low basal branching, which increases flower production and overall stem length.
- Slugs and snails damage young plants and earwigs ruin the flowers. Put down bait at planting time and periodically throughout the season. Sluggo Plus is an organic option that’s safe for both children and pets, and works well against all three pests.
- By midsummer, tall plants will require staking to keep them from falling over. For home gardeners with just a few plants, place tall, sturdy posts next to tubers at planting time so you can tie stems to them as they grow. For flower farmers the corral method is recommended, which involves placing a metal T-post every 8 feet along the outside edges of the beds and stringing a double layer of bailing twine from post to post.
- While dahlias are not a terribly long lasting cut flower, you can get 5-7 days from stems picked at the proper stage. Since dahlias don't open much after they've been harvested, it’s important to pick them almost fully open, but at the same time not overly ripe. Check the back of each flower head, looking for firm and lush petals versus papery or slightly dehydrated ones, which is a sign of age. Be sure to use floral preservative in the water.