Taking cuttings is a great way of increasing your stock of favorite dahlias inexpensively. Purchasing tubers can be expensive and often stressful as dahlia mania is real. The project is also a wonderful way of using time in the winter when we all get the itch to work toward the abundance of spring and summer gardens. You will need some basic supplies, including tubers that have been split with eyes. If you have saved some clumps from your own gardens, the clumps will first need to be washed and split. If you don’t know how to do this, please reach out and I will be happy to help with that process. You will also need to start early! Tubers take a fair amount of time to “wake-up.” I usually start the process in late January, but you can start as late as March or even early April.
Supplies needed:
- Tubers
- Small pots; I use square 4 inch that fit easily into 1020 trays
- Standard 1020 tray with no drainage holes
- Standard 1020 plug tray
- Propagation lid (you can find these locally at Blains)
- Potting or Pro Mix soil
- Plant labels.
- Rooting hormone (powdered works fine)
- Exacto knife
- Heat mat for seeding. This is crucial for success.
Steps:
- Select tubers from last year’s stock that have eyes (raised red bumps on the tuber).
- Plant into damp soil with the neck & eyes exposed. Label!
- Place the pot(s) in a warm and sunny place. Don’t water until green sprouts begin to grow from the eyes. If the soil dries out, you can spritz, but don’t water deeply as the tuber will rot. Be patient. Some tubers wake up quickly. Others can take 6 or 8 weeks to wake up.
- Once the sprout is around 3 inches or more, you can take the cutting. First prepare your 1020 trays. Fill the plug tray with damp, not wet, potting soil or pro mix. Fill the 1020 tray with no drainage holes ½ full of water and place the plug tray in it. Take a pencil and make holes in each plug all the way to the bottom. You want to be able to place the cutting so that the bottom tip reaches the bottom of the tray. The pre-made holes are important so that you don’t knock rooting hormone off the cutting as you place it into the tray. Pour a small amount of rooting hormone into the cap.
- Using an exacto knife, cut the new growth right at the tuber, taking care to get all of the new growth without cutting into the tuber itself. Strip off all of the extra foliage, leaving just a leaf or two at the tip. Dip the cutting into the rooting hormone, and then place the cutting all the way into one of the pre-made holes, making sure the cutting touches the bottom of the tray. Label each cutting or each row of the same variety.
- When the tray is full, or you are finished taking cuttings, place the propagation lid onto the tray. Place the tray onto your heat mat, with the temperature controlled at 70 degrees. You will leave the tray on the heat mat for at least 10 days. Around 8 days, you may notice that the cuttings don’t look great…they look like they may die. Don’t panic; this is normal. Usually the cuttings rebound around day 10. After they root, you can take the tray off the heat mat and repot the rooted cuttings and continue to grow under lights or in a very sunny spot until all threat of frost has passed and they are ready to be planted outside.
Don’t worry if your initial attempts don’t yield the results you want. It’s okay to kill plants; we all do. My first year of taking cuttings were very mixed; I probably had more seedlings die than survive. Each time I had a higher success rate, and I now enjoy the process. Seeing the new growth is always inspiring! Chrysanthemums are also easy to propagate through cuttings, so save a few in the fall and take on a fun winter project next year.