Congratulations! You have a dahlia tuber! Now what? Here are basics to help you get growing!
- Store your tuber in a cool, dark place until ready to plant. Keep the bag open so it can breath. Dahlias will rot with too much moisture before they grow.
- Dig a 4 to 5 inch deep hole in well draining soil in a location that gets at least 6 hours of direct sunlight per day. If planting more than one side by side then space them at the minimum of 12 inches apart. 18” is great if you have the space and 24” to 36” apart is usually recommended for dinner plate size dahlias. However, I have managed to grow dinner plate size dahlias 12” apart with success and found they supported each other well. To some degree, planting distance depends on your personal preference.
- Place tuber horizontally with the eye (where the plant will grow from) facing up. If you accidentally plant the eye a different direction the plant will make its way up. It might take a bit longer though. If you are growing in a pot then make sure it is deep and wide rather than tall and narrow. Allow 12” width minimum per dahlia in a pot. If it is a tall variety, be sure to stake your potted dahlia. Also keep in mind that potted dahlias require more frequent watering when they are growing. DO NOT WATER YOUR DAHLIA UNTIL IT IS GREEN ABOVE THE GROUND. Also consider using Slug bait. Slugs eat baby dahlias!
- If you have a dahlia that will grow taller than 3 ½ ‘ then put a sturdy stake in the ground with your tuber at planting time. Waiting to stake your dahlia after planting could cause damage to your tuber when you pound the stake into the ground. Alternatively, you can plant near a structure such as a fence or flag pole. Something sturdy to tie your dahlia to will help prevent the plant from falling over or breaking in high winds or intense rain.
- Adding bone meal to your soil under the tuber at planting time is beneficial but keep in mind that dogs are attracted to bone meal. My neighbor’s dog dug-up my tuber due to this attraction.
- When your dahlias are growing green above ground give them a very deep drink of water and then let them dry out. Repeat. Water more frequently during extremely hot temperatures. Dahlias don’t like soaking in water puddles so make sure you amend your clay soil to drain well.
- When your dahlia is about 12-18” tall you can pinch off the main stem to promote more side shoots & blooms. Cut your blooms frequently to promote more blooms! You can add a floral hydration fluid to your water to help extend vase life.
- After the 1st fall frost your dahlia plant will turn black. If you plan to lift your tubers for storage, let them sit for about 2 weeks after the 1st killing frost to build good dormancy skin. If there is a hard freeze in the forecast below 28° go ahead and lift them. A hard freeze can kill the tubers. Especially after a rain. If leaving in the ground then cut the stem below the soil line and mulch over the area heavily