Dahlias are generally easy plants to grow, and will reward you with bright, beautiful blooms that bring a splash of color to your garden. By paying attention and learning how to grow dahlia, you can enjoy these delightful blooms all summer long.
The best time to plant dahlia tubers is from mid-April throughout May, when the ground temperature is about 60 degrees. Choose an area that receives about eight hours of sunlight daily. If you live in a hot climate, choose a location that will provide sunlight in the morning, but shade in the afternoon.
Preparing Your Soil
Your soil needs to have good drainage and plenty of nutrients. If you are concerned about the nutrient level of your soil, adding peat moss, compost or other organic material will help improve the quality of your soil. Adding bone meal to the soil before planting the tubers is also a good option. The tuber should be planted about 4 to 6 inches deep, horizontally, about two feet apart. Cover the tubers with soil, but do not water them. Your dahlias should not be watered until the first sprouts appear. If you have chosen a variety of dahlia that grows over 3 feet tall, you will need to provide stakes.
Watering and Fertilizing
Once your dahlias are well established, providing a deep, 30-minute watering about two to three times weekly will suffice, with more frequent watering during hot or dry spells. Low-nitrogen fertilizer is best for dahlias – high nitrogen causes weak stems and small blooms. Choose one that is appropriate for vegetables for best results. Dahlias should receive their first fertilizer application within 30 days of their planting. After that, you can repeat the feeding in about three to four weeks, but be careful not to overfeed.