Dahlia can be produced from seed that is sown early indoors and transplanted outside after frost, from seed that is put directly in the garden after frost, or from potted plants or tubers. Planting Seeds Indoors: Use a seed starting kit to start seeds inside 8 weeks before the final frost. Seeds should be sown 1/4 inch deep in seed starting soil. Keep the soil moist but not wet. When the seedlings reach 4 inches tall, transfer them to larger pots. Set out when the soil has warmed up. Seeds can also be started outdoors using cold frames or under glass if the weather is cold enough. Remember to protect young plants from deer. When planting outside in the garden, provide some protection for the seedlings against rabbits, birds, and other predators.
Dahlias like well-drained soil with a high phosphorus content (15-20 pounds per 100 feet). In areas where this is a problem, try using sand instead of soil for planting dahlias. The silica in the sand helps supply nutrients as the plant grows.
Some varieties of dahlia need to be planted at least 10 years before they will produce flowers. Other varieties may be planted every year and still remain vegetative. If you want to grow dahlias for their flowers, start with these types. Otherwise, go with those listed as perennial.
Dahlias are very drought-tolerant once they have been watered regularly during dry periods.
Dahlias thrive in well-drained, sunny conditions. They like warm temperatures and will not endure frost. Plant dahlia tubers outside when the earth has warmed up after the latest frost date. By summertime, most dahlias will be in bloom. Let the blossoms fall where they may and cut the stems back to about 6 inches for another season of flowers.
Dahlias are hardy plants that can be divided every three years or so to keep them under control and to produce more flowers. Divide the tuber after it has been planted for at least two years. The new divisions should be planted 15 inches apart in average soil with adequate moisture. Dahlias need to be fertilized regularly with nitrogen-rich foods such as wheat bran or soybean meal.
There are many varieties of dahlias.
Dahlias are sensitive tubers that must be started under protection in early spring before being planted out after the frosts. Planting them out before the frosts have passed may cause them to become iced and die, so pot them up in March or early April. If you wait until later in the season to plant them, keep in mind that they need all-day sunlight to grow and will start to bolt (develop flower buds) when exposed to cold temperatures at night. Dahlias like well-drained soil with a high pH (8-9.5). When planting bulbs, don't cover them up completely, but rather leave an inch or two of green tissue showing above the ground for the first year after planting.
As far as varieties are concerned, there are three main groups: single flowers, which usually range in color from red to white; double flowers, which usually contain eight petals that are either red or white; and quadruple flowers, which often reach a height of over one foot and contain 16 large petals that can be any color except yellow. There are many more varieties than this, however, so you should get some good choices if you search around.
If you want to grow dahlias for sale, it is best to choose varieties that are popular and sell well because they are expensive to buy and grow. This way, you know you'll make money back on your investment.
Allow a few dahlia flowers to set seed so that you may pick them at the end of September. So, during the winter, store them in an envelope to seed in February. The emerging plants will have a fantastic variety of flower forms and colors. For example, there are red, orange, yellow, and green-and-white-striped varieties.
Dahlias are popular in cut flowers because of their large showy blooms that last for several weeks. However, unlike many other flowers that need to be replaced after they've faded, dahlias will keep getting better with age.
There are two types of dahlias: summer and winter. Summer-blooming dahlias should not be planted in temperatures below 55 degrees F. At these temperatures, the roots will not grow well. If you live in a cold region, consider purchasing "summer-warming" plants, such as daisies, when planting dahlias.
Winter-blooming dahlias do not require such low temperatures and can be planted any time of year. They usually bloom for only one week, but some continue to produce new flowers until frost kills the plant. Dahlias like full sun and average soil conditions. Average soil contains about 70 percent sand, 20 percent clay, and 10 percent organic matter. Well-drained soil is best.
Keep an eye on the weather in your area. Plant tubers only when the soil temperature is rising and the risk of frost has passed. Dahlias may be planted as early as September in frost-free coastal locations and will bloom three months later. They're sensitive to cold temperatures, so don't plant them where there was ice on the ground during the winter.
In warmer climates, you can start seeds indoors about 10 weeks before the expected last frost. Keep the plants outside under glass until the danger of frost has passed. Then move the plants into a garage or other unheated area for the remainder of the growing season.
Dahlias are drought-tolerant once they've reached 6 inches in height. Let the soil dry out between waterings if you want to encourage more flowers. Don't overdo it though - keep the soil moist but not wet.
Dahlias like full sun and average soil that's rich in nitrogen. If you live in a region with hot summers, choose varieties that do well with heat. Check out our list of hardy varieties if you need help choosing ones that will survive in your environment.
Dahlias are very popular and there are many different types to choose from. It's easy to grow your own, and they make great cut flowers too!