Table of Contents
- Introduction
- Storing Dahlia Tubers for the Winter
- Waking Up Dahlias: Containers and Soil for Spring
- Planting in the Garden: Soil and Permanent Containers
- Essential Elements for Your Containers
- Practical Scenarios for Different Gardeners
- Conclusion
- FAQ
Introduction
There is nothing quite like the late-summer magic of a dahlia garden in full bloom. Whether you are mesmerized by the dinnerplate-sized petals of a "Cafe au Lait" or the perfect geometric shapes of pompon varieties, these flowers bring a level of excitement that few other plants can match. At Longfield Gardens, we believe every gardener should experience the joy of harvesting a fresh bouquet of dahlias from their own backyard.
This guide focuses on the practical side of dahlia care, specifically answering what to put dahlia tubers in at every stage of their life cycle. We will cover the best materials for winter storage, the ideal soil for starting tubers in the spring, and the right containers for your permanent summer display. For a closer look at our dahlias, this guide is designed for home gardeners who want to ensure their tubers stay healthy, hydrated, and ready to perform.
Success with dahlias is achievable for gardeners of all skill levels when you get the basics right. For a closer look at PomPon Dahlias, choosing the correct containers and packing materials provides the foundation for vibrant, healthy plants.
Storing Dahlia Tubers for the Winter
Once the first frost arrives and your dahlia plants turn dark, it is time to think about winter storage. In most parts of the United States, dahlia tubers must be lifted and stored indoors to survive the cold. The goal of storage is to keep the tubers dormant, cool, and just hydrated enough so they do not shrivel. Choosing the right container and packing medium is the most important part of this process. For when to dig them, see our When to Bring Dahlia Bulbs In: Timing for Winter Storage guide.
Packing Materials for Storage
The material you use to surround your tubers acts as an insulator and a moisture regulator. You want a medium that is breathable but can hold a tiny bit of moisture if the air gets too dry.
- Pine or Cedar Shavings: Common wood shavings, like the kind used for animal bedding, are a favorite choice. They provide excellent airflow and help prevent the spread of rot between tubers.
- Vermiculite: This mineral is excellent at regulating moisture. It can absorb excess water if the tubers are too damp or release a little humidity if the environment becomes too dry.
- Peat Moss: This is a classic choice for many gardeners. It is lightweight and easy to handle, though it can be dusty. If you use peat moss, make sure it is very slightly damp—not wet—before packing your tubers.
- Newspaper: If you prefer a simpler approach, wrapping individual tubers in several layers of dry newspaper can be quite effective. This prevents tubers from touching each other, which stops potential rot from spreading.
Choosing the Right Storage Container
The "what" you put your tubers in depends largely on the humidity of your storage space. Most gardeners find success in a basement, crawl space, or cool garage where temperatures stay between 40°F and 45°F.
If your storage area is naturally damp, you should use breathable containers like cardboard boxes, paper bags, or open plastic crates. These allow excess moisture to escape, reducing the risk of mold. If your storage area is very dry, like a climate-controlled basement, you may prefer plastic bins or heavy-duty plastic bags. When using plastic, it is a good idea to leave the lid slightly cracked or poke a few small ventilation holes in the sides to ensure the tubers can still "breathe."
What to do next:
- Wait for a killing frost to blacken the foliage before digging.
- Gently brush off excess soil and let the tubers air-dry for a day in a protected spot.
- Place a layer of your chosen packing material in the bottom of a box or bin.
- Layer the tubers so they aren't touching, covering each layer with more material.
- Label every container or individual tuber with the variety name.
Waking Up Dahlias: Containers and Soil for Spring
Many gardeners choose to "pre-start" their dahlias indoors about four to six weeks before the last frost date. This gives the plants a head start and leads to earlier blooms in the summer. For timing, see our When is the Best Time to Plant Dahlia Bulbs? guide. At this stage, what you put your dahlia tubers in changes from a dry storage medium to a growing medium.
Potting Media for Starting Tubers
When you move tubers from storage to a pot, the soil should be light and well-draining. We recommend using a high-quality, professional potting mix rather than garden soil. For a step-by-step walkthrough, see our How to Plant and Grow Dahlia Tubers: A Step-by-Step Guide. Garden soil is often too heavy for pots and may contain pathogens that can harm young sprouts.
Look for a mix that contains a high percentage of composted bark, perlite, or peat. A "bark-heavy" mix is particularly helpful for dahlias because it provides the drainage they need while they are still forming new roots. During this early stage, the tuber has no roots to take up water, so the soil should be only slightly moist.
Ideal Pots and Trays
For individual tubers, a 4-inch to 6-inch plastic nursery pot is usually sufficient. This size provides enough room for the first flush of roots without requiring too much space under your grow lights or on a sunny windowsill.
If you are starting a large number of dahlias, you can use shallow nursery flats or plastic trays. Arrange the tubers closely together and cover them with an inch or two of potting mix. Once the sprouts are a few inches tall and have developed a small root system, you can carefully move them into individual pots or directly into the garden if the weather is warm enough.
The Plastic Bag Method for Blind Tubers
Sometimes it is hard to tell where the "eyes" (the growth points) are on a tuber after it has been in storage. If you have a tuber that looks healthy but shows no signs of sprouting, you can put it in a clear, one-gallon plastic bag with a handful of damp potting mix. Seal the bag and place it in a warm room. The humidity and warmth inside the bag will often encourage the eyes to pop within a week or two. Once you see a sprout, move the tuber into a traditional pot.
What to do next:
- Check your tubers for "eyes" or small green sprouts in late March or April.
- Fill a 6-inch pot halfway with lightly pre-moistened potting mix.
- Lay the tuber horizontally and cover it with 1-2 inches of soil.
- Place the pot in a warm, bright spot (around 65°F to 70°F).
- Do not water again until you see green growth poking through the soil.
Planting in the Garden: Soil and Permanent Containers
When the soil outside has warmed to at least 60°F and the danger of frost has passed, it is finally time to put your dahlias in their permanent summer home. This is the most exciting step, as it sets the stage for the coming floral display.
Choosing the Best Garden Spot
In the ground, what you put your dahlias in is all about the quality of the soil. Dahlias are "heavy feeders," meaning they need plenty of nutrients to produce those spectacular blooms. They also require excellent drainage. If your garden soil is heavy clay, the water may sit around the tubers and cause them to fail.
The best way to prepare a garden bed is to mix in a generous amount of finished compost or well-rotted manure. This improves the soil structure and provides a slow-release source of nutrients. We have found that dahlias perform best in a sunny spot that receives at least six to eight hours of direct sunlight each day.
Growing Dahlias in Containers
If you have limited garden space or want to decorate a patio, dahlias grow beautifully in large pots. However, because dahlias can grow quite large, you must choose a container that can support their weight and root system. For smaller border dahlias, a 2 or 3-gallon pot may be enough.
Make sure any container you use has large drainage holes. Because potted plants dry out faster than those in the ground, you will need to water more frequently once the plants are established. However, the same rule applies: wait until the plant is a few inches tall before you start a regular watering schedule.
Using Raised Beds
Raised beds are an excellent middle ground between garden soil and containers. They offer superior drainage and allow you to control the exact composition of the soil. When filling a raised bed for dahlias, use a mix of roughly 60% topsoil, 30% compost, and 10% potting medium or perlite. This blend provides the stability of native soil with the aeration of a potting mix.
Key takeaway for permanent planting: Success in the garden comes down to "right plant, right place." Ensure your dahlias are in a sunny spot with soil that drains well, and they will reward you with blooms all season long.
Essential Elements for Your Containers
Regardless of what you put your dahlia tubers in—whether it is a winter storage bin or a summer patio pot—there are three factors that will always determine your success: drainage, moisture, and temperature.
Proper Drainage
This is the most important rule for dahlia success. Dahlias do not like "wet feet." In storage, excess moisture leads to mold. In the garden, it leads to rot. Always ensure your pots have holes and your garden soil is loose enough for water to move through freely. If you are planting in a spot where water tends to puddle after a rain, consider a different location or use a raised bed.
Moisture Control
Watering is a skill that comes with observation. For tubers in storage, you want the medium to feel like a wrung-out sponge—barely damp. For newly planted tubers in the spring, the soil should be moist at planting time, but then left alone until the green shoots appear. Once the plant is growing vigorously and the weather is hot, dahlias will appreciate a deep watering once or twice a week.
Managing Temperature
Dahlias are tropical plants at heart. They love the warmth of the sun but need protection from freezing temperatures.
- In Storage: Keep them between 40°F and 45°F.
- In Spring: Use a warm room or a heating mat (set to 70°F) to wake them up.
- In Summer: Plant out only when the soil is warm.
If you live in a very hot climate, your dahlias might appreciate a little afternoon shade to keep the roots from overheating in their containers.
Practical Scenarios for Different Gardeners
The way you handle your dahlia tubers often depends on your specific living situation. Here are a few common scenarios and the best containers for each:
The Apartment Gardener If you only have a balcony, stick to dwarf or border varieties. Put your dahlia tubers in 3-gallon plastic or ceramic pots. These varieties don't require heavy staking and will provide plenty of color in a compact space. Use a high-quality potting mix with added perlite for the best results.
The Cold-Climate Gardener If you live in the North, your growing season is short. To get the most out of your dahlias, put your tubers in 6-inch pots indoors in April. By the time the ground is warm enough to plant in late May or June, you will have a sturdy plant that is ready to start budding. If you're ordering online, check our Shipping Information for timing.
The Flower Farmer or Large-Scale Hobbyist If you are growing dozens of dahlias, individual pots may be impractical. Instead, put your tubers in large plastic bulb crates lined with newspaper. This allows you to "pre-sprout" hundreds of tubers at once in a relatively small space. For a closer look at flower forms, see our Dahlia Forms for Garden and Vase.
Conclusion
Getting the most out of your dahlias starts with understanding what to put them in at each phase of their growth. From the cedar shavings and cardboard boxes of winter storage to the nutrient-rich compost and large patio pots of summer, each container serves a specific purpose. By matching the right vessel and material to the plant's needs, you ensure a healthy life cycle for these spectacular flowers, backed by our 100% Quality Guarantee.
At Longfield Gardens, we want to help you fill your home and garden with beauty. Growing dahlias is a rewarding journey that offers a wonderful return on your time and effort. With the right containers and a little bit of patience, you will soon be enjoying a season filled with incredible color.
- Select breathable containers for damp storage and sealed containers for dry storage.
- Use light, bark-based potting mix for starting tubers in the spring.
- Ensure permanent garden spots or large pots have excellent drainage.
- Wait for green growth before starting a regular watering routine.
"Dahlias are incredibly resilient. Once you provide them with the right environment and a sturdy container, they do the hard work of creating some of the most stunning blooms in the botanical world."
Order your favorite Dahlia Collections today and get ready for a spectacular summer display!
FAQ
What is the best material to pack dahlia tubers in for winter?
The most popular materials are pine or cedar shavings, vermiculite, and peat moss. These materials help regulate moisture and insulate the tubers. If you have a very humid storage area, wood shavings are often the best choice because they allow for better airflow.
Can I store dahlia tubers in plastic bags?
Yes, you can use plastic bags if your storage area is very dry, such as a climate-controlled basement. However, it is important to poke a few small holes in the bag or leave the top slightly open to prevent moisture from building up, which could cause the tubers to rot.
What kind of soil should I use when planting dahlias in pots?
Use a high-quality, well-draining potting mix rather than garden soil. A mix that contains composted bark or perlite is ideal, as it ensures that water can move away from the tuber easily. This is especially important in the early spring when tubers are prone to rot if kept too wet. For a broader overview, see our All About Dahlias guide.
How big should a pot be for a full-sized dahlia?
For standard, tall Dinnerplate Dahlias, you should use a container that holds at least 5 to 7 gallons of soil. The pot should be approximately 12 to 15 inches deep and wide. This provides enough weight to prevent the plant from tipping over and enough room for the roots to support a large, blooming plant.