How to Grow Dahlias from Cuttings Step by Step

Table of Contents

1. Introduction
2. The Benefits of Growing Dahlias from Cuttings
3. When to Start Your Dahlia Cuttings
4. Essential Supplies for Success
5. Step 1: Waking Up the Mother Tubers
6. Step 2: How to Take the Cutting
7. Step 3: Sticking and Rooting
8. The Importance of Light and the 14-Hour Rule
9. Caring for Your New Cuttings
10. Potting Up and Feeding
11. Moving to the Garden
12. Summary of the Cutting Process
13. Common Questions and Realistic Expectations
14. Conclusion
15. FAQ

Introduction

There is a unique sense of wonder that comes with watching a tiny green shoot transform into a spectacular, dinnerplate dahlia bloom. While most gardeners are familiar with planting tubers in the spring, there is another rewarding way to fill your garden with even more color: growing dahlias from cuttings. This simple technique allows you to turn a single tuber into a dozen or more identical plants, ensuring your garden is overflowing with your favorite varieties.

At Longfield Gardens, we love helping home gardeners discover new ways to make their yards more beautiful. Growing from cuttings is a budget-friendly and highly effective method for increasing your flower production without needing extra space for winter storage. Whether you want to create a dedicated cutting garden or simply want more of a rare variety, this process is accessible to gardeners of every skill level.

In this guide, we will walk you through the entire process, from waking up your tubers early to the moment you transplant your new starts into the garden. You will learn the best environment for rooting and how to ensure your new plants grow strong and healthy. By the end of this article, you will have the confidence to multiply your dahlia collection and enjoy a more productive growing season than ever before.

The Benefits of Growing Dahlias from Cuttings

If you have ever found a dahlia variety that you absolutely love, you know the desire to have it everywhere in your landscape. Growing from cuttings, often called "vegetative propagation," is the most efficient way to achieve this. Unlike growing from seeds, which results in a brand-new hybrid that won't look like the parent plant, cuttings are exact clones. You get the same height, the same petal structure, and the exact same color you fell in love with.

One of the most surprising benefits of this method is the vigor of the resulting plants. Many professional growers find that plants grown from cuttings often bloom earlier and more profusely than those grown directly from a tuber. This is likely because the plant doesn't have to spend energy waking up a large, dormant tuber; instead, it starts its life with a fresh, active root system.

Additionally, taking cuttings is an excellent insurance policy. If you have a variety that is known to be a "poor tuber maker"—meaning it produces small or thin tubers that are difficult to overwinter—taking cuttings ensures you don't lose that variety if the original tuber fails to sprout the following year. It is a productive, enjoyable way to spend the late winter months while waiting for the ground to thaw.

When to Start Your Dahlia Cuttings

Timing is everything when it comes to successful propagation. To have plants that are large enough to go into the garden by late spring, you need to start the process indoors while the weather is still cold. For most gardeners in the United States, this means bringing your tubers out of storage in late February or early March.

The goal is to give yourself about 8 to 10 weeks before your last expected frost date. This window provides enough time for the tuber to sprout, for you to take several "flushes" of cuttings, and for those cuttings to develop a robust root system before they move outdoors. If you start too late, your cuttings may still be quite small when it’s time to plant; if you start too early, they may become root-bound and leggy before the soil is warm enough for them.

We recommend checking your local frost dates and working backward. For example, if your last frost is in mid-May, aim to start "waking up" your tubers in late February. This schedule allows you to take your first cuttings in March and have sturdy, 6-inch plants ready for the garden by the time the soil temperature reaches a consistent 60°F.

Essential Supplies for Success

You don't need a professional greenhouse to grow dahlias from cuttings. Most of these items are already in your garden shed or can be easily found at a local garden center. Keeping your workspace clean is the most important factor, as young cuttings are more susceptible to rot than established plants.

• Healthy Tubers: Start with firm, plump tubers that have visible "eyes" or have already begun to sprout.
• Trays or Shallow Pots: You’ll need these to "wake up" the mother tubers.
• Rooting Medium: A sterile, soil-less mix is best. You can use a mix of peat moss and perlite, or professional seed-starting mix. Avoid heavy garden soil, which can harbor bacteria.
• Sharp, Sterile Knife: A dedicated garden knife or even a simple box cutter works well. Just be sure to clean it with rubbing alcohol between different varieties.
• Rooting Hormone: While not strictly necessary, a rooting powder or gel can speed up the process and increase your success rate.
• Small Pots or Plug Trays: For the individual cuttings to grow in once they are taken.
• Humidity Dome or Plastic Bags: These help keep the air around the cuttings moist while they develop roots.
• Heat Mat: Providing gentle bottom heat (around 70°F) encourages faster root development.
• Grow Lights: Since you are starting in late winter, natural windowsill light is usually not strong or long enough.

Key Takeaway: Success starts with cleanliness. Always use sterile potting mix and clean your cutting tools frequently to prevent the spread of soil-borne issues to your vulnerable new starts.

Step 1: Waking Up the Mother Tubers

Before you can take cuttings, you need shoots. To get these, you must encourage your dormant tubers to start growing. We call the tuber you take cuttings from the "mother tuber."

Fill a shallow tray with a few inches of damp potting soil or vermiculite. Lay your tubers on the surface. You don't need to bury them deep; in fact, leaving the "neck" and "crown" of the tuber exposed makes it much easier to see the shoots as they emerge. Place the tray on a heat mat in a bright spot.

Keep the soil lightly moist but never soggy. Within 10 to 14 days, you should see small, reddish-green bumps appearing at the crown. These are the eyes beginning to push. Soon, they will grow into sturdy green stems. Once these stems are about 3 inches tall and have at least two sets of leaves, they are ready to be harvested as cuttings.

Step 2: How to Take the Cutting

This is the most critical part of the process. There are two common ways to take a dahlia cutting: the "heel" cut and the "node" cut.

The Heel Cut

The heel cut is highly recommended for beginners because it includes a tiny sliver of the mother tuber’s skin at the base of the stem. This area is packed with natural growth hormones that help the cutting root very quickly. To do this, use your sharp knife to slice just slightly into the tuber itself, taking the stem and a small "heel" of tuber tissue with it.

The Node Cut

If you want the mother tuber to continue producing more shoots from the same spot, you can perform a node cut. Instead of cutting into the tuber, you cut the stem just above the lowest pair of leaves (the node). The piece you remove becomes your cutting. The "stump" left behind on the tuber will often sprout two new stems, allowing you to take even more cuttings later.

Once you have removed the shoot, look at the base. If there are leaves very close to the bottom, gently snip them off. You want about an inch of bare stem at the bottom to insert into your rooting medium. If the top leaves are very large, you can cut them in half horizontally. This reduces the amount of moisture the plant loses through its leaves while it doesn't have roots to drink with.

Step 3: Sticking and Rooting

After taking your cutting, work quickly so the stem doesn't wilt. If you are taking many cuttings at once, keep them in a glass of shallow water until you are ready to "stick" them into their pots.

1. Dip the Stem: Dip the bottom half-inch of the stem into rooting hormone. Tap off any excess.
2. Prepare the Hole: Use a pencil or a small stick to make a hole in your damp rooting medium. Never push the cutting directly into the soil, as this can wipe off the rooting hormone.
3. Insert and Firm: Place the cutting into the hole and gently press the soil around the base to ensure good "soil-to-stem" contact.
4. Label Everything: This is vital! Cuttings all look the same when they are small. Use a waterproof marker to label the variety name and the date you took the cutting.

What to do next:

• Place the pots on a heat mat set to 70°F.
• Cover with a humidity dome, leaving a small gap for airflow.
• Position under grow lights for 14–16 hours a day.
• Check daily for moisture; the soil should feel like a wrung-out sponge.

The Importance of Light and the 14-Hour Rule

One of the most common reasons dahlia cuttings fail is a lack of light—specifically, the duration of light. Dahlias are photoperiodic, which means they react to the length of the day.

In nature, dahlias begin to form tubers when the days get shorter in late summer and fall. If your young cuttings only receive 10 or 12 hours of light, their biology tells them it’s time to make a tiny tuber rather than growing roots and leaves. This can cause the cutting to "stall" or stop growing entirely.

To keep your cuttings in "growth mode," they need at least 14 to 16 hours of light every day. Since the sun isn't up that long in March, you must use supplemental grow lights. A simple shop light with LED or fluorescent bulbs works perfectly. Keep the lights just a few inches above the tops of the plants to prevent them from stretching and becoming "leggy."

Caring for Your New Cuttings

For the first week, your cuttings are essentially on life support. Because they have no roots, they cannot take up water. They rely on the humidity in the air to stay hydrated. If you see them wilting significantly, mist the inside of the humidity dome with water.

After about two weeks, you should see signs of life. The most obvious sign is new growth at the very top of the cutting. This usually indicates that roots have begun to form underneath. You can also give the cutting a very gentle tug. If you feel resistance, the roots are holding onto the soil.

Once roots are established, you can gradually remove the humidity dome. Start by taking it off for an hour a day, then two, then four, until the plants can sit in the open air without wilting. This "hardens" the leaves to the lower humidity of your home.

Potting Up and Feeding

When you see roots coming out of the bottom of your plug tray or small pot, it is time to move the cuttings into a slightly larger container—usually a 3-inch or 4-inch pot. Use a high-quality potting mix that contains some nutrients, as the sterile rooting medium you used earlier likely has none.

This is also the time to start a gentle fertilization routine. Because these young plants are growing rapidly, they need fuel. Use a balanced, water-soluble fertilizer diluted to half-strength once every two weeks. This will help them develop strong stems and deep green leaves.

If your cuttings start to grow very tall and thin, don't be afraid to pinch them. Once the plant is about 6 to 8 inches tall and has three sets of leaves, snip off the very top growing tip. This might feel counterintuitive, but it encourages the plant to branch out from the sides, resulting in a much bushier, sturdier plant with more flowers later in the season.

Moving to the Garden

The transition from a cozy indoor environment to the great outdoors is a big step for a young dahlia. You cannot move them directly from your grow lights to the full sun, or the leaves will sunburn and die. This transition period is called "hardening off."

Wait until all danger of frost has passed and the soil is warm. Start by placing your pots in a sheltered, shady spot outside for just two hours on the first day. Each day, give them an hour or two more of dappled sunlight. By the end of a week, they should be able to handle a full day of sun.

When you are ready to plant dahlias, dig a hole slightly larger than the pot. We recommend planting the cutting a little deeper than it was in the pot—up to the first set of leaves. This encourages the plant to develop a deeper root system and can even result in a better crop of tubers at the end of the year.

Summary of the Cutting Process

Growing dahlias from cuttings is a cycle of patience and observation. While it requires a few more steps than simply burying a tuber in the dirt, the rewards are worth the effort. You gain a deeper understanding of how these plants grow and end up with a full line of dahlias for a fraction of the cost.

Key Takeaway: The secret to successful dahlia cuttings is the combination of warmth (70°F), high humidity during the first two weeks, and at least 14 hours of consistent light to prevent premature tuber formation.

• Start mother tubers 8–10 weeks before the last frost.
• Take 3-inch cuttings with a "heel" of the mother tuber whenever possible.
• Use sterile medium and rooting hormone to prevent rot.
• Provide long "days" using grow lights to keep the plant growing upward.
• Harden off gradually before planting in the garden.

Common Questions and Realistic Expectations

Gardening is a partnership with nature, and results can vary based on your local climate and indoor conditions. Not every cutting will take, and that is perfectly okay! Even professional growers expect a small percentage of loss. If a cutting turns black at the base, simply remove it, clean your tray, and try again.

The most important thing is to keep the environment consistent. Fluctuations in temperature or letting the rooting medium dry out completely are the most common setbacks. With a little practice, you will find a rhythm that works for your space.

Many gardeners ask if these cuttings will produce tubers for next year. The answer is a resounding yes! By the end of the growing season, a plant started from a cutting will have developed its own cluster of tubers underground. You can dig, store, and replant these just like any other dahlia.

Conclusion

Mastering the art of growing dahlias from cuttings is one of the most satisfying skills a gardener can develop. It turns a single purchase from Longfield Gardens into a lifetime of beautiful blooms and allows you to share your favorite varieties with friends and neighbors. By following these steps—focusing on timing, light, and clean technique—you can significantly expand your garden and enjoy the vibrant colors of dahlias from mid-summer until the first frost.

The process may seem detailed at first, but once you see those first tiny roots appear, the "magic" of propagation becomes addictive. Remember to take it one step at a time, observe your plants closely, and enjoy the journey of creation.

• Start your tubers early to give cuttings a head start.
• Prioritize light duration to keep plants in the growth phase.
• Transition plants slowly to the outdoors to avoid shock.

Ready to start your dahlia journey? Explore our wide selection of premium dahlia tubers at Longfield Gardens and find the perfect varieties to multiply in your own backyard.

FAQ

How long does it take for a dahlia cutting to root?

Under ideal conditions—with bottom heat and high humidity—most dahlia cuttings will begin to form roots within 10 to 14 days. You will know they have rooted when you see new leaf growth at the top of the stem or feel resistance when giving the plant a very gentle tug. Some varieties root faster than others, so don't worry if a few take up to three weeks.

Do I need to use rooting hormone for dahlia cuttings?

While dahlias are vigorous and can root on their own in damp soil, using a rooting hormone (powder or gel) significantly increases your success rate. It helps the cutting seal the "wound" where it was cut and provides the chemical signal the plant needs to stop making stem cells and start making root cells. It is a small investment that makes the process much more reliable for beginners.

Can I take cuttings from a dahlia plant growing in the garden?

Yes, you can take cuttings throughout the summer, but they are generally harder to root than the soft, succulent growth that comes off a tuber in the spring. Summer stems are more "woody" and the air is often drier, which makes wilting a bigger problem. If you take summer cuttings, ensure you keep them in a very shaded, humid environment until roots form.

Will a plant grown from a cutting bloom in its first year?

Absolutely. In fact, plants grown from cuttings often grow faster and bloom sooner than those grown from tubers because they don't have to break dormancy; they are already in an active growth state. They will produce the same size and quality of flowers as the mother plant and will also form a brand-new clump of tubers by the end of the season.