Dahlia Care & Growing Info
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Depending on your climate and region, Dahlias grow best in full sun to part shade. They should get at least six hours of sunlight per day. In warmer climates like mine, afternoon shade can help the flowers by keeping them cooler. Afternoon shade can give the bloom a more accurate color to its variety. For growers in warm climates – shade cloth will be your best friend!! Dahlias shut down when temperatures reach 90 degrees. They do not like it and must conserve energy that slows growth or blooms. I will post details on my setup for the warm South Carolina climate. I have used 40% shade cloth and had great results.
Plant tubers 4-6 inches deep in well-drained soil – I can't talk enough about well-drained and the impact that has on success. The soil pH should be around 6.5. Dahlias are heavy feeders at the beginning of the season. Dahlia plants are also foliar feeders that can take in nutrition through their leaves. Spray fertilizers can be used on dahlias. When left in the ground over winter, tuber loss is frequently due to the tubers freezing or too much water collecting around the tuber. To avoid this, add a nice layer (4-6") of compost in the fall after you have cut down the old stalks. When digging and dividing tubers for winter, make sure they are dry before you store them and store them in a cool, dark spot that will not freeze during the winter.
Before planting - move stored tubers into a warm, dark spot around April 1st to get tubers to "eye up" and sprout. Around April 15th, go through tubers and toss those damaged or rotted. For earlier blooms, plant in pots and keep protected until the last frost, then plant outside based on your last frost dates. I'm in South Carolina, so my planting date is April 15th through May 1st. Spring rains will also occur – cover your beds or areas with a tarp if you have clay soil or soil that does not drain well. This is critical. Newly planted tubers are highly susceptible to rot. Dahlias may take 90 to 120 days to bloom but will continue until they are killed by a frost in the fall.
In the fall, cut all stalks to about 6-9 inches tall after the first frost or November 1st. Dig and divide two weeks later, or add mulch to protect against freezing if left in the ground. Again, if your soil does not drain well, cover or dig! It's not just the cold that is the mortal enemy—it's moisture! I learned this the hard way during my first and second years of planting in spring!
Plant tubers 4-6 inches deep in well-drained soil – I can't talk enough about well-drained and the impact that has on success. The soil pH should be around 6.5. Dahlias are heavy feeders at the beginning of the season. Dahlia plants are also foliar feeders that can take in nutrition through their leaves. Spray fertilizers can be used on dahlias. When left in the ground over winter, tuber loss is frequently due to the tubers freezing or too much water collecting around the tuber. To avoid this, add a nice layer (4-6") of compost in the fall after you have cut down the old stalks. When digging and dividing tubers for winter, make sure they are dry before you store them and store them in a cool, dark spot that will not freeze during the winter.
Before planting - move stored tubers into a warm, dark spot around April 1st to get tubers to "eye up" and sprout. Around April 15th, go through tubers and toss those damaged or rotted. For earlier blooms, plant in pots and keep protected until the last frost, then plant outside based on your last frost dates. I'm in South Carolina, so my planting date is April 15th through May 1st. Spring rains will also occur – cover your beds or areas with a tarp if you have clay soil or soil that does not drain well. This is critical. Newly planted tubers are highly susceptible to rot. Dahlias may take 90 to 120 days to bloom but will continue until they are killed by a frost in the fall.
In the fall, cut all stalks to about 6-9 inches tall after the first frost or November 1st. Dig and divide two weeks later, or add mulch to protect against freezing if left in the ground. Again, if your soil does not drain well, cover or dig! It's not just the cold that is the mortal enemy—it's moisture! I learned this the hard way during my first and second years of planting in spring!