Are Dahlias Grown From Seeds or Bulbs?

Table of Contents

1. Introduction
2. The Short Answer: Tubers vs. Seeds
3. Growing Dahlias from Tubers
4. Growing Dahlias from Seeds
5. Right Plant, Right Place: Which Should You Choose?
6. Essential Care for All Dahlias
7. Understanding Your Climate and Timing
8. Common Simple Fixes
9. The Joy of the Harvest
10. Conclusion
11. FAQ

Introduction

There is a unique kind of magic in watching the first dahlia of the season unfurl its petals. Whether it is a massive dinnerplate dahlia the size of a dinner plate or a perfectly symmetrical ball dahlia, these flowers are the crown jewels of the late-summer garden. At Longfield Gardens, we believe every yard has room for these spectacular bloomers. They offer a rewarding experience for gardeners of all skill levels, providing an explosion of color just when other summer flowers begin to fade.

If you are planning your garden, you might find yourself wondering: are dahlias grown from seeds or bulbs? The answer is actually both, but the path you choose depends on what you want to achieve in your backyard. In this guide, we will explore the differences between growing from seeds and growing from tubers—which are often referred to as bulbs—to help you decide which method is right for your space.

Understanding the biology of these plants makes gardening feel less like a mystery and more like a fun, achievable project. By the end of this article, you will have a clear plan for adding these vibrant flowers to your landscape.

The Short Answer: Tubers vs. Seeds

When people ask if dahlias grow from bulbs, they are usually thinking of tubers. While they look a bit like potatoes, tubers are thickened underground stems that store energy for the plant. True bulbs, like tulips or daffodils, have layers like an onion. Tubers are solid.

You can grow dahlias from either seeds or tubers, but the results are very different. Most home gardeners prefer tubers because they provide a predictable result. If you buy a specific variety, such as the creamy-pink Cafe au Lait, a tuber ensures you get that exact flower.

The deep purple Thomas Edison is another classic example.

Seeds, on the other hand, are a bit of a biological lottery. Because dahlias have a complex genetic structure, a seed gathered from a specific plant will not look like its parent. It will be a brand-new variety that has never existed before. This makes seeds exciting for those who love surprises but less ideal for gardeners who have a specific color palette or garden design in mind.

Growing Dahlias from Tubers

Growing from tubers is the most common way to enjoy these flowers. It is the "gold standard" for anyone who wants large, showy blooms and consistent heights. At Longfield Gardens, we focus on providing high-quality tubers because they are the most reliable way to create a beautiful, planned landscape.

Why Choose Tubers?

The primary reason to choose tubers is consistency. Every tuber is a clone of the mother plant. This means if you plant a row of Kelvin Floodlight dahlias, every single one will be a bright, lemon-yellow dinnerplate variety of the same height. This predictability makes it easy to plan your garden beds.

Tubers also give the plant a head start. Because the tuber contains a large amount of stored energy, the plant grows quickly once the soil warms up. You will generally see larger flowers and a more robust plant in the first season compared to most seed-grown varieties.

Identifying the "Eye"

If you are new to dahlia tubers, the most important thing to look for is the "eye." The eye is a small growth point located on the neck of the tuber, where it connects to the old stem. It looks like a tiny bump or a green sprout.

Without an eye, a tuber cannot grow a plant. We ensure our tubers are healthy and have viable eyes, but if you are looking at your own stored tubers in the spring, it can take a little patience to spot them. Sometimes, placing them in a warm, bright spot for a few days helps the eyes "wake up" and become more visible.

Planting Tubers for Success

Getting your tubers in the ground is a straightforward process. The most important rule is to wait for the right timing. Dahlias are tropical plants and do not like cold soil.

1. Wait for the warmth: Do not plant your tubers until the danger of frost has passed and the soil is at least 60°F.
2. Pick a sunny spot: Dahlias need at least six to eight hours of direct sunlight every day.
3. Check the drainage: Drainage simply means how fast water leaves the soil. Dahlias like moisture but will rot if they sit in soggy earth.
4. Dig a hole: Place the tuber about 4 to 6 inches deep. Lay it horizontally with the eye pointing upward.
5. Hold the water: This is a key tip for beginners. Do not water the tuber immediately after planting unless your soil is bone-dry. Wait until you see the first green shoots peeking through the soil before you start a regular watering schedule.

For a step-by-step refresher, see How to Plant Dahlias.

Key Takeaway: Tubers are clones of the parent plant. Choose them if you want specific colors, shapes, and sizes that match your garden plan exactly.

Growing Dahlias from Seeds

Growing dahlias from seeds is a different experience entirely. It is often more affordable if you want to fill a very large area, and it is a favorite for those who enjoy the "treasure hunt" aspect of gardening.

The Genetic Surprise

As mentioned, dahlia seeds do not grow "true to type." If you plant a seed from a tall, red cactus dahlia, you might get a short, yellow single-petal flower. While you can buy seed mixes that are grouped by certain traits—like "Bishop’s Children," which usually features dark foliage—the flower colors will still be a mix.

Most seed-grown dahlias tend toward "open-centered" flowers. These are flowers where the yellow center is visible to bees and butterflies. Because pollinators can easily reach the nectar and pollen, seed-grown dahlias are fantastic for a pollinator-friendly garden.

Starting Seeds Indoors

Dahlia seeds have a relatively long growing season. To get flowers before the first frost of autumn, you usually need to start them indoors.

• Timing: Start your seeds about 6 to 8 weeks before your last expected spring frost.
• Setup: Use a seed-starting mix and small trays. A heat mat can help speed up germination, which is the process of the seed sprouting.
• Light: Once the seedlings emerge, they need a lot of light. A bright south-facing window or a simple shop light held just a few inches above the plants will keep them from getting "leggy" (tall and weak).
• Hardening off: Before moving them to the garden, spend a week gradually introducing the seedlings to the outdoors. Start with an hour in the shade and slowly increase their time in the sun.

For a full walkthrough, see How to Grow Dahlias from Seed.

Do Seed-Grown Dahlias Make Tubers?

One of the most interesting things about dahlias is that even if you start them from a tiny seed, the plant will grow its own clump of tubers underground by the end of the summer.

If you find a flower you absolutely love among your seedlings, you can dig up those tubers in the fall, store them, and replant them next year. From that point forward, those tubers will produce an exact clone of that new, unique flower you "discovered" in your garden.

Key Takeaway: Seeds are best for gardeners on a budget or those who want to support pollinators. Every seed-grown dahlia is a unique surprise that will eventually produce its own tubers.

Right Plant, Right Place: Which Should You Choose?

Deciding between seeds and tubers is easier when you look at your garden goals. We recommend matching the method to the specific "job" the plant needs to do in your yard.

Choose Tubers If:

• You have a color scheme: If you are designing a "white garden" or a "sunset border," tubers are the only way to ensure the colors match.
• You want massive blooms: The giant dinnerplate dahlias that everyone admires are almost always grown from tubers.
• You are short on time: Planting a tuber in May is much faster than tending to seedlings indoors starting in March.
• You want cut flowers: If you want long-stemmed, florist-quality blooms for bouquets, professional-grade tubers are your best bet.

Choose Seeds If:

• You have a lot of space: If you have a large meadow or a back corner that needs a lot of plants for very little money, seeds are very cost-effective.
• You love pollinators: Single-flowered dahlias grown from seed are a favorite for bees.
• You enjoy the process: If you find the act of starting seeds indoors rewarding and don't mind the extra steps, seeds are a fun winter project.
• You want to "breed" flowers: Every time you grow from seed, you are technically creating a new variety.

Essential Care for All Dahlias

Regardless of whether you started with a tuber or a seed, the care requirements for dahlias are largely the same once they are established in the garden. Getting a few basics right will ensure you have flowers from July through the first frost.

The "Deep Water" Rule

Dahlias are thirsty plants, but they don't like to be "constantly" wet. The goal is to water deeply, letting the moisture soak down to the roots, and then let the top inch of soil dry out slightly before watering again.

If you have sandy soil, you may need to water more often. If you have heavy clay soil, you must be careful not to overwater, as the moisture can get trapped around the tubers and cause them to soften or rot.

Pinching for More Blooms

One of the best "simple wins" in dahlia gardening is a technique called pinching. When your plant is about 12 inches tall, use your fingers or a pair of clean garden snips to remove the very top of the center stem.

This might feel like you are hurting the plant, but it actually does the opposite. It tells the plant to stop growing one tall, thin stalk and instead start growing multiple side branches. This results in a bushier plant with significantly more flowers.

For a step-by-step refresher, see How to Pinch and Stake Dahlias.

Staking and Support

Dahlias can grow quite large, and their flower heads are often heavy. A summer rainstorm or a gust of wind can easily topple a tall plant.

It is best to put your support in place at the time of planting so you don't accidentally poke a hole through the tuber later. For individual plants, a sturdy bamboo stake or a metal tomato cage works well. If you are growing a long row, you can use stakes and twine to create a "corralling" system that keeps the plants upright.

What to Do Next:

• Check your local frost dates to determine your planting window.
• Choose a sunny, well-draining spot in your garden.
• If using tubers, wait for green shoots before starting a regular watering routine.
• Pinch the center stem when the plant reaches 12 inches to encourage more flowers.

Understanding Your Climate and Timing

At Longfield Gardens, we time our shipping based on your USDA hardiness zone. If you are not sure of your zone, check our Hardiness Zone Map.

Dahlias are not "hardy" in most of the United States. This means they cannot survive a freezing winter in the ground. In zones 8 through 11, you might be able to leave them in the ground with a thick layer of mulch. However, for most of us in zones 3 through 7, the tubers must be dug up and stored indoors for the winter or treated as annuals and replaced each spring.

For a step-by-step guide, see How to Lift and Store Dahlia Bulbs.

We ship our tubers to arrive about two weeks before the ideal planting time for your specific zone. For details on delivery timing and rates, see our Shipping Information.

Because weather can be unpredictable, always check your local 10-day forecast before planting. If the ground is still cold and soggy, it is better to wait a week than to rush the tubers into the soil.

Common Simple Fixes

If your dahlias aren't performing quite like you expected, don't worry. Most issues can be solved by looking at three main factors: sun, water, and soil.

1. Plenty of Sun: If your plant is tall and "stretchy" but has very few flowers, it likely needs more sun. Dahlias are sun-worshippers. They need that direct light to fuel the energy required to create those intricate blooms.
2. Air Circulation: If you notice a white, dusty substance on the leaves, this is usually powdery mildew. It isn't a disaster, but it means the leaves aren't drying off fast enough. Next year, try spacing your plants a bit further apart to allow the wind to move through the foliage.
3. Soil Nutrients: Dahlias are heavy feeders. They use a lot of "food" to grow so quickly. Mixing a bit of compost into the soil before planting provides a steady supply of nutrients. If you use a fertilizer, look for one that isn't too high in nitrogen, as too much nitrogen can lead to lots of green leaves but very few flowers.

The Joy of the Harvest

One of the greatest rewards of growing dahlias is the ability to bring them inside. They are one of the most productive cut flowers you can grow. In fact, the more you cut dahlias for bouquets, the more flowers the plant will produce.

When cutting for a vase, look for flowers that are almost fully open. Unlike roses or lilies, dahlias do not open much once they have been cut. Use a clean pair of snips and place the stems immediately into warm water. With fresh water every day, a dahlia bouquet can easily last five to seven days, brightening up your kitchen or dining room.

Conclusion

Whether you choose to plant tubers for a specific, breathtaking look or seeds for a fun and unpredictable garden journey, dahlias are a rewarding addition to any home. They bridge the gap between summer and autumn, providing a final, glorious display of color when the rest of the garden is winding down.

At Longfield Gardens, our goal is to make this process as easy and successful as possible for you. By focusing on the basics—sun, drainage, and timing—you can grow flowers that look like they belong in a professional floral magazine. Gardening should be a source of joy and relaxation, and there is no flower quite like the dahlia to remind us of the beauty that a little soil and sunshine can create.

• Tubers provide clones and consistent, large blooms.
• Seeds offer genetic variety and are excellent for pollinators.
• Timing is everything: Wait for warm soil and the end of frost.
• Simple care wins: Pinching and staking make a massive difference in your results.

"The secret to a successful dahlia garden isn't a green thumb; it's simply matching the plant's needs for sun and warmth with a little bit of patience."

Ready to start your own dahlia journey? Explore our Planning Guide for Dahlias to find the perfect varieties for your garden this season.

FAQ

Can I grow dahlias from seeds I saved from my own garden?

Yes, you can certainly save seeds from your own dahlias once the flower heads have dried on the plant. However, remember that the new plants will not look like the parent plant. They will be unique hybrids created by the bees moving pollen from one flower to another, which can lead to fun and unexpected results.

Do dahlias grown from seeds flower in the first year?

Yes, dahlia seedlings grow very quickly and will typically produce flowers by mid-to-late summer of their first year. While they may start a bit later than plants grown from tubers, they will still provide a beautiful show of color before the first frost of the season.

Is it better to buy dahlia bulbs or seeds for a beginner?

For most beginners, we recommend starting with tubers (often called bulbs). Tubers have more stored energy, making them more resilient to minor mistakes, and they provide the predictable colors and shapes that help a new gardener feel successful and confident in their results.

Are dahlia "bulbs" and tubers the same thing?

In the gardening world, the terms are often used interchangeably, but technically they are different. Dahlias grow from tubers, which are modified roots. True bulbs, like onions or lilies, have fleshy scales. When you see "dahlia bulbs" for sale, they are almost always tubers. For more on the difference, see Dahlia Tubers: What You Need to Know.