Dahlias are among the easiest flowers to grow, and all tubers regardless of size, will produce equally strong plants and prolific blooms.
After purchasing your dahlias, remove them from the plastic bag you may have received them in and store the tubers in a cool (50 degrees is ideal) dark place until planting time.
LOCATION: Dahlias grow best in well-drained soil protected from wind. Full sun is ideal, but they will tolerate some shade.
SPACING: Space your dahlias according to the size of the blooms: giants and mediums should be 2' to 3' apart. Small, miniatures, and pompon dahlias about 2' apart.
SOIL PREPARATION: About two weeks before planting, broadcast 5-10-10 (potato fertilizer) over the soil, and spade it in. Add sand to improve drainage: peat moss or compost to loosen clay soils. Avoid nitrogen fertilizers (for lawns) they cause excess leaf growth and weaken the blooms.
PLANTING: Plant after last frost, from May 1st to June 15th. Remove about 4" to 6" of soil, place tuber flat with the growing point upward. For taller varieties, place a stake 6" from the tuber. Cover the tuber with soil.
SUMMER CULTIVATION: Since dahlias have many surface roots, only light weeding is needed. After July, cultivate no deeper than 2" and no closer than 1" from the stalk. Unless the weather is very dry, dahlias will need very little water until they begin to bloom. Then water thoroughly: soak ground every 10 days if needed. if a low, compact bush is desired, pinch out the center growing point when the plant is about 2' high. For larger blooms, pinch out the two side buds, leaving the central bud to grow at the end of each branch. In areas where slugs are common, use slug bait regularly until plants are 2" high. For leaf eating insects and aphids, spray plants when infestations occur with diaznon and/or insecticidal soaps. For best results spray early in the morning or late in the day.
CUT FLOWERS: Depending on the variety, you can expect to have from 8 blooms (giants) to over 100 blooms (pompon's) per tuber this summer. To ensure continuous blooming from August until frost remove all dead blossoms. Cut flowers very early or late in the day, place blooms in warm water (100 degrees) for 1/2 hour, then place in cold water. If displayed in a cool part of the home (not in direct sunlight) and the water in the vase is changed daily, the dahlias will last a week.
DIVIDING DAHLIAS: You can divide tubers in the fall, or in the spring. If you have never divided before, spring is best as it is the easiest time to see the eyes. If eyes are difficult to see, we recommend dividing the clump in half, or quarters. Not all tubers will have an eye. Cut surfaces should be allowed to dry thoroughly before storing, or planting if dividing in the spring. Tuber size does not affect plant growth so even the smallest tuber will produce a full size plant if it has a live eye. Different varieties produce different size and shape tubers.
AIR CLEANING TUBERS:
About 3 years ago, instead of using water to wash my tubers, I switched to air cleaning (air compressor) my tubers. When I washed my tubers with water I lost 15 to 20 percent of my tubers. Since I began air cleaning, my loss of tubers is less than 1 percent. I dig one day, air clean, cut, air dry and put the tubers into storage the next day. I have sandy loam soil and this works for me. I maintain 40-45 degree Fahrenheit temperature in my storage room. I put the tubers in cedar shavings in plastic grocery bags and then into cardboard boxes with tops of bags and boxes left open. In 6-8 weeks I check the tubers for rot and shriveling.