Tips for Growing Dahlias:
Dahlias should be planted in an area that receives full sun (at least 6-8 hours of direct sunlight) and has well-drained soil.
Plant after all danger of frost has passed when soil temperature is around 60°F.
Dig a hole wide enough for the tuber and 4"-6" deep. Place tuber horizontally with growing eye facing up.
Cover with soil. Plant tubers 12"-18" apart. Put a label next to the tuber to keep track of where they are and the cultivar.
Most dahlias will need some sort of staking to prevent them from falling over. If you only have a few plants you can do this by putting a single stake next to each plant and tying the stem to it as it grows, being careful not to hit the tuber with the stake. If you’re growing rows of dahlias, we prefer the corral method. Put stakes on both sides of your rows. We space them every 5 feet-we find doing them a little closer like this prevents the string from sagging over time. Tie heavy duty twine around each post, forming a “corral”. We also tie the twine across the rows diagonally after going around the perimeter for extra support. Start your first layer about a foot off the ground, then two more layers about 12 inches apart. Add more if needed.
Wait to water until sprouts are visible above the soil (unless you have very dry soil, and even then, it should be just damp). Watering before this can cause the tuber to rot. Make sure heavy or extended rain isn't in the forecast before planting.
They can be watered once they sprout above the soil and generally need about an inch of water per week once established.
When your plant is around 12" tall and has 3-4 sets of leaves pinch the center shoot. This will cause the plant to form lateral branches, which leads to more blooms. While pinching isn’t necessary, it’s recommended to not only increase the amount of flowers, but also for sturdier plants and more usable stems.
Deadhead spent blooms to promote the growth of more flowers.