How to Propagate Dahlias How to Propagate Dahlias
You can easily propagate dahlias by means of seeds, cuttings, or tuber division.
Step 1 – Dig Up a Dahlia Bulb
After the first frost of the season has darkened the foliage of a dahlia plant, you must dig it out and store it indoors, because dahlia bulbs are not frost hardy. First, cut the dahlia plant to a stem about 6 inches in height. Use a shovel or garden fork to dig the soil around the plant, taking care not to damage the tubers in the process. Once the soil is loose, carefully remove the dahlia with the bulb. Check the bulb for any signs of softness or rot. If the bulb is not firm and healthy looking, it must be discarded. Make sure the tubers have prominent buds or eyes, which are small growths, white in color.
Step 2 – Store the Dahlia Bulb
Clean and divide the tubers. Gently tap off the soil around the tubers and wash the bulb. Divide the bulb into several parts, making sure each division is healthy, has buds, and includes a part of the stem. Discard the central tuber from which the plant has sprouted. Store the divisions in a dark and cool area, by placing 5 or 6 of them in a plastic bag with some shredded paper. Prick several small holes in the bag so that the tubers will be aerated. Keep the tubers moist by sprinkling small amounts of water as required. Excess water will cause rot. Inspect the tubers once in a while and discard any that look damaged or diseased.
Step 3 – Plant the Dahlia Tubers
When you plant the dahlia tubers in spring, make sure the ground has warmed up, and that there is no chance of frost. Amend the planting site in advance, by de-weeding it and amending it with compost and bonemeal. Plant the tuber with the eye facing upwards and backfill with soil. Water till the soil is moist. The plant will soon send up shoots. You can now use cuttings from a healthy dahlia plant to grow new plants. To prepare a cutting, first select a healthy shoot that is 3 to 4 inches in height. Use a sharp, sterilized knife to remove it with a piece of the underlying tuber. Remove the lower leaves of the shoot, while neatly trimming and evening out its base. Brush some rooting hormone on the bottom of the cutting, and plant it about an inch deep in a small pot filled with potting mix. Cover the pot with a plastic bag. After the cuttings form roots in 3 to 4 weeks, you can transplant them into larger pots. You can collect seeds from finished blooms and propagate dahlias as well, by sprinkling the seeds on potting mix, and later transplanting the seedlings to larger pots.