Table of Contents
- Introduction
- Why Grow Dahlias From Cuttings?
- The Best Time to Start Your Cuttings
- Essential Supplies for Success
- Step 1: Waking Up the Tubers
- Step 2: Taking the Cutting
- Step 3: Planting and Rooting
- Step 4: Providing the Right Environment
- Potting Up Your Rooted Cuttings
- Hardening Off: The Transition to the Outdoors
- Planting in the Garden
- What to Expect: Blooms and Tubers
- Troubleshooting Common Success Steps
- Summary of the Cutting Process
- FAQ
Introduction
There is a unique kind of excitement that comes with seeing the first green sprouts of a dahlia tuber emerge in the spring. For many of us, dahlias are the highlight of the summer garden, offering an incredible variety of colors and shapes that last until the first frost. If you have ever wished you had five or ten more plants of your favorite variety, you are in luck.
At Longfield Gardens, we believe that gardening should be a rewarding and accessible hobby for everyone, and our dahlia collections are a great place to start. Taking dahlia cuttings is one of the most satisfying ways to expand your flower beds without a lot of extra effort. It is a simple technique that allows you to turn a single tuber into several healthy, blooming plants in just one season.
This guide will explain the step-by-step process of growing dahlias from cuttings, from waking up your tubers to planting your new starts in the garden. Whether you are a beginner or a seasoned grower, you will find that this method is an easy win for a more beautiful yard. Growing dahlias from cuttings is a practical and enjoyable way to multiply your garden's beauty while ensuring your favorite varieties thrive year after year.
Why Grow Dahlias From Cuttings?
The most common way to grow dahlias is by planting tubers directly in the ground. However, taking cuttings offers several advantages that make it a favorite technique for enthusiasts. Understanding why this method works so well can help you decide if it is the right choice for your garden this year. If you want to explore compact forms, browse our Single Dahlias.
Multiply Your Flower Count
The most obvious benefit is the ability to create more plants. A single healthy dahlia tuber can produce several sprouts. If you let that tuber grow naturally, you get one large plant. If you take cuttings from those sprouts, you can often get three, four, or even five separate plants from that same tuber. By the end of the summer, your garden will be filled with even more blooms for cutting and enjoying. If you want a ready-made mix, see our Dahlia Dinnerplate Daybreak Collection.
Healthier Plants and Faster Blooms
Cuttings often grow with surprising vigor. Because they start with a fresh root system and are usually started indoors in a controlled environment, they can sometimes outpace plants grown from tubers. Many gardeners find that plants grown from cuttings actually begin blooming a week or two earlier than those grown from tubers planted at the same time. The stems are often strong, and the flowers are just as large and vibrant as you would expect.
Overwintering Difficult Varieties
Some dahlia varieties are known for producing small or "grassy" tubers that can be difficult to store through the winter. If you have a favorite variety that doesn't seem to survive well in the cellar, taking cuttings in early spring is a great insurance policy. It allows you to "rescue" the variety and ensure you have a healthy plant ready for the new season.
Saving Space
When you take cuttings, you are essentially creating clones of the mother plant. This is a very space-efficient way to start your garden. You can keep several dozen cuttings in a small area under grow lights during the chilly weeks of early spring, whereas planting all those tubers in large pots would require a much larger setup.
Key Takeaway: Taking cuttings is a budget-friendly and space-efficient way to multiply your favorite dahlias, often resulting in plants that bloom earlier and grow more vigorously than traditional tubers.
The Best Time to Start Your Cuttings
Timing is everything in gardening, and dahlia cuttings are no exception. To have plants that are ready to go into the ground once the weather warms up, you need to start the process while there is still a chill in the air.
In most parts of the United States, the best time to start "waking up" your dahlia tubers for cuttings is late winter or early spring, typically February or March. This gives the tubers enough time to sprout and the cuttings enough time to develop a strong root system before the last frost date. If you're not sure which zone you garden in, check our hardiness zone map.
Since these young plants are sensitive to cold, they must stay indoors or in a heated greenhouse until all danger of frost has passed. Starting about 8 to 10 weeks before your local last frost date is usually the "sweet spot" for success. If you start too early, the plants may become too large for their indoor pots. If you start too late, they won't have much of a head start over tubers planted directly in the garden.
Essential Supplies for Success
You do not need a laboratory or expensive equipment to grow dahlias from cuttings. Most of what you need can be found at a local garden center or in your own potting shed. Keeping things simple ensures the process remains fun and stress-free. If you're ordering from Longfield Gardens, our Shipping Information page explains the schedule.
- Healthy Tuber: Start with a firm, healthy dahlia tuber that has at least one visible "eye" or sprout.
- Shallow Trays or Pots: You will need a container to hold the tubers while they sprout. A shallow plastic tray or a wide, 1-gallon pot works well.
- Potting Mix: Use a lightweight, sterile potting soil or a mix of peat and perlite. Avoid using heavy garden soil, as it doesn't provide enough air for new roots.
- A Sharp, Clean Knife: A small craft knife or a dedicated gardening knife is essential for making clean cuts.
- Rooting Hormone: While not strictly necessary, a quick dip in rooting powder or gel can help the cutting establish roots faster.
- Small Pots or Cell Trays: These will hold your individual cuttings once they are removed from the tuber.
- Light Source: Because you are starting these indoors, you will need a grow light or a very bright, south-facing window.
- Humidity Dome or Plastic Bag: This helps keep the air around the cuttings moist while they are forming roots.
Step 1: Waking Up the Tubers
Before you can take a cutting, you need a sprout. To get your tubers growing, you must provide them with a little bit of warmth and moisture. This process is often called "pre-sprouting" or "potting up."
Fill a shallow tray with a few inches of damp potting mix. Lay your tubers on top of the soil. You do not need to bury them deeply; in fact, leaving the "neck" and "head" of the tuber exposed makes it much easier to see the sprouts as they emerge. For more on tuber anatomy, read Dahlia Tubers: What You Need to Know.
Place the tray in a warm spot, ideally between 65°F and 70°F. You don't need bright light at this exact moment, but as soon as you see the first green tips appearing, move the tray under your grow lights. Keep the soil lightly damp but never soggy. Excess water can cause the tuber to rot before it has a chance to grow.
Step 2: Taking the Cutting
Once your dahlia sprouts are about 3 to 4 inches tall, they are ready to be harvested. This is the most exciting part of the process, and it is much simpler than it sounds. If you like a classic dinnerplate look, browse our Dahlia Dinnerplate Cloud Nine Collection.
Identifying the Best Stems
Look for stems that are sturdy and have at least two sets of leaves. You want to avoid very thin, spindly sprouts, as they may struggle to root. The best cuttings are those that look healthy and vibrant.
Making the Cut
There are two ways to take a cutting. The first is called a "basal cutting." This involves using your sharp knife to take a tiny sliver of the tuber's skin along with the sprout. Cuttings taken with this small piece of tuber "flesh" often root the fastest because the growth hormones are highly concentrated in that area.
The second method is a "nodal cutting." For this, you simply cut the sprout just above where it meets the tuber, or just below a "node." A node is the bump on the stem where leaves emerge. Dahlias have a high concentration of natural rooting hormones at these nodes.
Preparing the Cutting
Once you have removed the sprout, gently trim off the lowest set of leaves. This leaves a bare section of stem that will go into the soil. If the remaining leaves are very large, you can cut them in half with your scissors. This sounds counterintuitive, but it actually helps the plant. Large leaves lose moisture quickly through a process called transpiration. By reducing the leaf size, you help the cutting stay hydrated while it doesn't have roots to drink with.
What to do next:
- Select a sprout that is 3–4 inches tall.
- Use a sterilized knife to cut the sprout near the base.
- Remove the bottom leaves to expose the stem.
- Optionally, dip the end of the stem in rooting hormone.
Step 3: Planting and Rooting
Now that you have your cutting, it needs a home where it can grow its own roots. Fill your small pots or cell trays with a fresh, damp potting mix. If you're building a color mix for later, try the Dahlia Dinnerplate Berry Spritz Collection.
Use a pencil or a small stick to poke a hole in the soil. This prevents the rooting hormone from being rubbed off when you push the stem into the dirt. Insert the cutting so that at least one node (where you removed the leaves) is buried beneath the soil surface. Gently firm the soil around the stem to ensure there are no air pockets.
The Importance of Humidity
Since the cutting has no roots, it cannot take up water from the soil yet. It must stay hydrated by absorbing moisture from the air. This is why humidity is the "secret ingredient" for success.
Place a clear plastic dome over your tray, or put the entire pot inside a clear plastic bag. This creates a miniature greenhouse effect. Place the cuttings in a bright spot, but avoid direct, hot sunlight, which can cook the tender sprouts inside the plastic.
Watching for Signs of Life
In about 10 to 21 days, your cuttings should begin to develop roots. You will know they are successful when you see new, bright green growth at the top of the plant. Resist the urge to tug on the cuttings to check for roots! This can snap the delicate new fibers. If the plant looks perky and is growing new leaves, the roots are doing their job.
Step 4: Providing the Right Environment
To ensure your cuttings grow into strong, garden-ready plants, you need to manage three main factors: light, temperature, and water.
The 14-Hour Light Rule
One interesting fact about dahlias is that they are sensitive to the length of the day. This is known as photoperiodism. When the days are short (less than 12 hours of light), dahlias naturally want to produce tubers. When the days are long (more than 14 hours of light), they focus on growing leaves and roots.
To get your cuttings to form strong "feeder roots" rather than tiny, premature tubers, you should provide at least 14 to 16 hours of light per day. A simple shop light or LED grow light on a timer is the easiest way to achieve this. Keep the lights just a few inches above the tops of the plants to prevent them from getting "leggy" or stretched out.
Temperature and Airflow
Dahlias love a comfortable room temperature. Aim to keep your growing area between 65°F and 75°F. If the room is too cold, growth will stall. If it is too hot, the plants may wilt.
Once the cuttings have rooted and you have removed the humidity dome, it is a good idea to have a small fan nearby to provide gentle airflow. This strengthens the stems and helps prevent common indoor plant issues like mold or "damping off," which is a condition where young stems rot at the soil line.
Watering Wisely
Watering is a balancing act. The soil should feel like a wrung-out sponge—moist but not dripping. If the soil is too dry, the young roots will wither. If it is too wet, the stem may rot. Check your plants daily by sticking your finger an inch into the soil. If it feels dry, give them a gentle drink. For a deeper dive, see How Much to Water Dahlia Tubers.
Potting Up Your Rooted Cuttings
Once your cuttings have filled their small starter cells with roots, it is time to give them a little more room to grow. This is usually about 3 to 4 weeks after you first took the cutting.
Carefully move the young plant into a 3-inch or 4-inch pot filled with high-quality potting soil. This is also a great time to start a light feeding schedule. At Longfield Gardens, we recommend using a balanced, water-soluble fertilizer at half-strength every two weeks. This provides the nutrients the plant needs to build a strong structure before it heads out to the garden.
When you pot them up, you can plant the stem slightly deeper than it was before. This encourages more roots to form along the buried portion of the stem, leading to a sturdier plant. Don't forget to move your labels! It is very easy to lose track of which variety is which once they are out of their original trays.
Key Takeaway: Moving your cuttings into slightly larger pots and providing a gentle fertilizer gives them the boost they need to transition from a delicate sprout to a robust garden plant.
Hardening Off: The Transition to the Outdoors
Your dahlia cuttings have lived a pampered life indoors. They have had perfect temperatures, consistent light, and no wind. Before they can survive in the garden, they need to be toughened up. This process is called "hardening off." For more on when young plants are ready to move, see How Big Should Dahlias Be Before Planting Out?
Wait until the nighttime temperatures in your area are consistently above 50°F. Start by taking your plants outside for just an hour or two, placing them in a sheltered, shady spot. Bring them back inside before the temperature drops in the evening.
Every day, increase the amount of time they spend outside and gradually move them into more direct sunlight. Over the course of 7 to 10 days, the plants will develop a thicker "skin" and stronger stems that can handle the elements. By the end of the week, they should be ready to stay outside overnight and be planted in their permanent home.
Planting in the Garden
When it is finally time to plant, treat your dahlia cuttings much like you would any other garden transplant. Choose a spot that gets at least 6 to 8 hours of direct sunlight. Good drainage is essential, as dahlias do not like "wet feet." If you are shopping for a bigger display, our Dahlia Dinnerplate Summer Lovin Collection is a nice next stop.
Dig a hole slightly larger than the pot. A helpful tip for cutting-grown dahlias is to remove the very bottom set of leaves and plant the cutting deep enough so that the node where those leaves were is buried under the soil. This specific technique encourages the plant to grow a large cluster of tubers underground, which you can then dig up and store at the end of the season.
Water the new plants in well and provide them with a stake if they are a tall variety. Because cuttings often grow faster than tubers, they may need support sooner than you expect.
What to Expect: Blooms and Tubers
One of the most common questions gardeners ask is: "Will a cutting actually produce a tuber for next year?" The answer is a resounding yes!
The First Season
In its first summer, a dahlia grown from a cutting will look identical to one grown from a tuber. It will reach its full height and produce an abundance of flowers. In fact, because the plant doesn't have to rely on the energy stored in an old tuber, it often develops a very efficient and healthy root system that results in beautiful, high-quality blooms.
The Fall Harvest
When frost arrives in the autumn and the foliage turns brown, it is time to dig up your dahlias. When you lift a plant that was started from a cutting, you will find a brand-new clump of tubers waiting for you. These tubers are clones of the original plant. You can store these over the winter just like any other dahlia tubers, and next spring, you can start the whole process over again with even more stock!
Troubleshooting Common Success Steps
Even the most careful gardener can run into a few hurdles. Here is how to handle the most common situations with a positive, simple approach.
If Cuttings Wilt
If your cuttings look droopy right after you take them, don't panic. They have just lost their main water source. Ensure your humidity dome is tight and the soil is damp. Usually, they will perk back up within 24 hours as they adjust to their new environment.
If Roots Take a Long Time
Some varieties are simply slower to root than others. If your cutting still looks green and healthy but hasn't shown new growth after two weeks, just be patient. As long as the stem isn't mushy, it is likely still working on those roots. Ensure the temperature is warm enough, as cold soil is the number one cause of slow rooting.
If Stems Look "Leggy"
If your plants are getting very tall and thin, they are telling you they need more light. Move your grow lights closer to the plants—usually 2 to 4 inches above the leaves is ideal. You can also "pinch" the top of a leggy plant once it has three sets of leaves to encourage it to grow bushier rather than taller.
Summary of the Cutting Process
Growing dahlias from cuttings is a rewarding journey that turns one tuber into a garden full of flowers. By following a few simple steps, you can master this technique and enjoy more dahlias than ever before. For a broader overview, see All About Dahlias.
- Start Early: Wake up tubers indoors 8-10 weeks before the last frost.
- Take Clean Cuttings: Use a sharp knife and include a node or a bit of tuber.
- Focus on Humidity: Keep cuttings covered until they develop roots.
- Provide Long Days: Use 14+ hours of light to ensure root growth.
- Harden Off Gradually: Take a week to introduce plants to the outdoor world.
Taking dahlia cuttings is one of the most effective ways to fill your garden with color. By following the natural rhythms of the plant and providing a little extra light and warmth in the spring, you can easily multiply your favorite varieties.
At Longfield Gardens, we are here to help you succeed in every step of your gardening journey. Whether you are planting your first tuber or taking your hundredth cutting, the joy of watching these spectacular flowers bloom is something every gardener should experience. For more tips on growing beautiful flowers, we invite you to explore our other guides and planning resources. Learn more about our approach on our About Us page.
FAQ
Can I take cuttings from a dahlia plant growing in the garden?
While it is possible, it is much harder to get these to root successfully because the plants are often already focused on blooming. It is much easier and more reliable to take cuttings from young sprouts in the early spring while the plant is in its most vigorous vegetative growth phase.
Do I need to use rooting hormone for dahlia cuttings?
It is not strictly required, but it does help. Rooting hormone contains auxins, which are natural plant chemicals that signal the stem to stop growing leaves and start growing roots. Using it often results in a higher success rate and faster root development, especially for beginners.
Will a cutting bloom the same year it is planted?
Yes! One of the best things about dahlia cuttings is that they mature very quickly. They will typically reach full size and begin blooming at the same time as, or even earlier than, dahlias grown from tubers. You won't have to wait an extra year for flowers.
How many cuttings can I take from one tuber?
This depends on the variety and the health of the tuber. Generally, you can safely take 3 to 5 cuttings from a single tuber. After you have taken your cuttings, you can even plant the original tuber in the garden, and it will grow a new set of sprouts and bloom just like normal.