How to Take a Dahlia Cutting: A Step-by-Step Guide

We are now at that point during the winter season where the days are slowly getting longer and darkness no longer dominates our days.  We have hope that Spring is just around the corner, but, the groundhog saw his shadow and is predicting 6 more weeks of winter.  And all we want to do is to start gardening and to start making those dahlia garden visions we have in our head come true!

Well, not all is lost.  It's the perfect moment to inspect how your tubers are storing. While it might not be the most thrilling activity, take this opportunity to retrieve some dahlia tubers for pre-sprouting and take some dahlia cuttings to expand your collection of your coveted varieties.

In this blog, we’ll explore why gardeners take dahlia cuttings, the tools you’ll need, and a step-by-step guide to successfully propagate your dahlias.  

Why Take Dahlia Cuttings?

Taking dahlia cuttings offers several advantages:  

1. Preserve Desirable Traits:  Storing dahlias during the winter is one of the most complicated activities we do when growing dahlias.  Cuttings ensure that you will have this variety to grow this summer should something happen to your tubers in storage.
2. Cost-Effective Propagation:  Tubers can be quite costly and instead of buying new tubers of the same variety or waiting for a summer or two to get multiple tubers you can create multiple plants from a single parent dahlia by taking a cutting.
3. Faster Blooms:  Cuttings often produce flowers sooner than plants grown from tubers. 
4. You get to garden during the winter months!

Tools and Equipment Needed

Before you start, gather the following tools and materials to pre-sprout the tuber.

For pre-sprouting the tubers:

• Small pots or seed trays with drainage holes 
• Well-draining potting mix

To take cuttings:

• Sharp, scalpel or cutting blade.  
• Rooting hormone (powder or gel) - we use Garden Safe TookRoot rooting hormone.  It doesn’t cost much and it works well for us.  There are many other options and some people swear by those.  But, we have also had good success without any rooting hormone as long as the other growing conditions are met.
• Well-draining potting mix or growing plugs like Root Riot or Qplugs.  We use Qplugs as they are compostable and we don’t get the mess you get with soil.
• A clean workspace and disinfectant(10% bleach to water solution).  Viruses can be transferred from your scalpel or cutting surface from one cutting to another.  To further mitigate virus transfer we can take cuttings without a scalpel or cutting blade or work surface, but, we don’t cover that process in this blog.
• A spray bottle for misting.
• A warm, bright location or grow lights.

Step-by-Step Guide to Taking Dahlia Cuttings

1. Choose the Right Time

• The best time to take dahlia cuttings is in early spring when the tubers are getting ready to sprout.  The entire process from pulling a tuber out of stock to a ready to plant cutting can take 8-12 weeks.  So, count back from your planting time accordingly.

2. Plant the Tuber

• Inspect the tuber for any signs of rot or damage.
• Fill your pot or tray with the well-draining potting mix.
• Moisten the soil lightly so it’s damp but not soggy.  
• Place the tuber horizontally in the soil with the eye (growth point) facing upward.  
• Cover the tuber with about 1-2 inches of soil, leaving the eye slightly exposed or just barely covered.
• If planting multiple tubers, space them 4-6 inches apart to allow room for growth. 
• Place the pot or tray in a consistently warm(65 to 70 degrees F) location. 
• Light - Place the pot in a bright location with indirect sunlight or under grow lights.
• Watering - Keep the soil lightly moist but not waterlogged. Overwatering can cause the tuber to rot. 

3. Monitor Growth 

• Sprouts should emerge within 2-4 weeks, depending on the variety and conditions.
• Once the sprouts are 3-4 inches tall and have at least two sets of leaves, they are ready for cuttings.  

4. Prepare Your Tools and Workspace

Sanitation is critical to prevent the spread of viruses or diseases. Sterilize your cutting blade or with a 10% bleed to water solution.  We have 10 scalpels to insure our blades are sterile and have been in the solution for at least 2 minutes.  Clean your pots or trays as well.

5.  Take Cuttings

• Gently remove soil from around the base of the sprout and the crown of the tuber.
• Using your sterilized scalpel, cut the sprout just above the tuber, but, below the first set of leaves.
• Trim the cutting to within a 1/8th inch from the first set of leaves, removing the lower leaves to expose the stem.  This leaf node is where the cutting will develop roots.  If the  sprout has 3 sets of leaves we also remove the 2nd set of leaves and this will become a 2nd rooting point.
• We then reduce the size of the leaves by 1/2 to reduce the loss of moisture due to transpiration.

6. Apply Rooting Hormone

• Dip the cut end of the stem into rooting hormone to encourage root development. Shake off any excess powder or gel.  

7. Plant the Cutting

• Fill your pots or trays with well-draining potting mix.  Moisten the soil.
• Make a small hole in the soil and insert the cutting, ensuring the exposed stem is buried.  
• Gently firm the soil around the cutting. 
• If you are using a Root Riot or a Qplug as show in the picture the small hole is premade and you simply insert the cutting into the hole in the plug.

8. Provide Optimal Conditions and monitor daily

• Place the trays in a warm, bright location with indirect sunlight or under grow lights(14 hours of light per day).
• Mist the cuttings daily if you observe dryness to maintain humidity.
• Once roots develop(usually in 2-4 weeks), you can transplant the cuttings into larger pots.   

9. Potential Complications and How to Mitigate Them

1. Cuttings rot - soil is too wet or soil isn’t well draining.
2. Wilting cuttings - not enough humidity or temperatures are too high.  Continue misting.
3. Slow rooting - low temperatures or inadequate light.

Conclusion  

Taking dahlia cuttings is a rewarding and cost-effective way to expand your garden. By following these steps and paying attention to sanitation and care, you can successfully propagate healthy, vibrant dahlia plants. Whether you’re a seasoned gardener or a beginner, this method allows you to enjoy more of these stunning blooms while preserving the unique qualities of your favorite varieties.  

Happy gardening! 🌸