Start dahlias indoors to get early blooms
Sooners were settlers who entered what is now the state of Oklahoma before or “sooner” than March 2, 1889, when the land was free to anyone who entered and occupied an area.
Many Sooners hid in ditches at night to abruptly appear to stake their claim hours ahead of legal settlers. We gardeners always want things sooner rather than later.
You can get flowers sooner by potting up dahlia tubers, growing them indoors until it’s warm enough to transplant them out into the garden after the weather warms up. Pot them up in rich soil and give them plenty of light.
Fill a flat or pot with a well-drained potting mix. Lay the dahlia tubers on their side and cover with potting soil. Water well, but don’t let the soil get soggy.
Keep them indoors in a warm, sunny spot. Once the leaves appear, you can fertilize with a weak liquid organic food. Harden off the dahlias before you plant them outdoors. Keep in mind that you’ll have to acclimate the young dahlias gradually to the outside.
Once the nights have warmed up, and you are ready to plant them outdoors, set the pots outside every day for a few hours in a shaded spot, then take them back inside at night. Every day for a week to 10 days, increase the amount of direct light and the time they spend outdoors. This will prevent them from getting sunburned once you put them into the garden.
Dahlias bloom from midsummer until killed by the first frost. Their blossoms come in all colors except blue and range in size from the huge 10-inch “dinner plate” blooms to the 2-inch lollipop-style pompons. You can find dahlias that will stay reasonably small or others that grow up to five feet high. For bushier plants, pinch the growing tips when they get six inches tall. If you kept your own tubers over the winter, only plant those that are not moldy or shriveled.
In the garden, dahlias do best in rich, well-drained soil in full sun. Because they can get quite tall, look for a spot out of direct wind. If you are growing dahlias for cut flowers, plant them in rows right in the vegetable garden. The shorter dahlias can be mixed into any sunny flowerbed.
Your dahlias will start blooming in just six to eight weeks after you set them out. Because dahlias don’t do well in cold soil, you often can’t set the tubers out until late May or early June.
Plant dahlia tubers whole, with the growing points, or “eyes” facing up. Bury them six to eight inches deep. Go easy on the water until you see the first green shoots. Too much water will rot the tubers.
Dahlias are heavy feeders, meaning they need plenty of fertilizer to grow well. Start out with a high-nitrogen liquid, fertilizing every week in early summer, then switch to a high-potassium fertilizer to encourage blooms.
After your dahlia foliage blackens with the first frost, carefully dig them up to store them over the winter. Come next spring you will be ready to pot them up and get them off to a good start once the soil warms up. You will get dahlia blooms a lot sooner by starting them indoors, and as any Oklahoman knows, sooner is better than later.