Table of Contents
- Introduction
- The Ideal Temperature for Canna Storage
- Temperature for Curing: The First Step
- How to Prepare Canna Rhizomes for Storage
- Choosing the Best Storage Medium
- Finding the Perfect Spot in Your Home
- Storing Cannas in Containers
- Checking Your Rhizomes Throughout the Winter
- Transitioning Cannas in the Spring
- Conclusion
- FAQ
Introduction
Few plants bring the vibrant, tropical energy of the cannas to a summer landscape. Their lush foliage and bold, colorful blooms turn any garden into a personal paradise from midsummer until the first frost. While these beauties are easy to enjoy during the warm months, gardeners in cooler climates often wonder how to keep them safe through the winter. Storing these tender plants is a rewarding way to save your favorite varieties and enjoy even bigger displays year after year.
At Longfield Gardens, we want to make the process of overwintering your plants as simple and successful as possible. Many gardeners find the idea of storing bulbs a bit mysterious, but it really comes down to getting a few environmental factors right. This guide will walk you through the specifics of timing, preparation, and the exact temperatures needed to keep your cannas healthy until spring.
The key to success lies in understanding the dormancy needs of the plant and providing a stable environment. By following a few straightforward steps, you can ensure your canna rhizomes survive their winter nap. Learning what temperature to store canna bulbs is the most important part of this seasonal transition.
The Ideal Temperature for Canna Storage
When you bring your canna rhizomes indoors for the winter, your primary goal is to keep them in a state of deep sleep, also known as dormancy. To achieve this, you must keep them in a cool, stable environment. The sweet spot for storing canna bulbs is between 40°F and 55°F.
Staying within this range serves two purposes. First, keeping the temperature below 60°F prevents the rhizomes from trying to grow too early. If the storage area is too warm, the canna may use up its stored energy trying to push out sprouts in the dark. Second, the temperature must stay above freezing (32°F). Cannas are tropical plants, and their fleshy roots contain a lot of water. If the temperature drops below freezing, the water inside the cells will expand and destroy the plant tissue, leading to mushy, dead rhizomes.
Staying Within the 40°F to 55°F Range
Most home gardeners find that an unheated basement or a cool crawl space naturally sits within the 40°F to 55°F range. If you have an attached garage, the area near the interior wall often stays at a safe, cool temperature. However, it is a good idea to use a simple thermometer to check the spot before you commit your plants to it for the season.
If your storage area stays closer to 40°F, the plants will remain perfectly dormant. If the area trends closer to 55°F, you may want to check them more frequently toward the end of winter to ensure they aren't starting to wake up. Consistency is better than a specific number within that range, as wild swings in temperature can stress the dormant plant.
Why Temperature Fluctuations Matter
Extreme shifts in temperature can signal to the plant that the seasons are changing. If a storage room gets warm during a sunny week and then drops back down to near-freezing, the rhizome may begin a cycle of starting and stopping its growth process. This drains the energy the plant needs for a strong start in the spring.
Choosing a spot that is well-insulated from the outdoors is the best way to maintain a steady temperature. Interior closets in a cool part of the house or the center of a basement are usually more stable than a spot near a window or an exterior door.
Key Takeaway: For the best results, aim for a consistent storage temperature between 40°F and 55°F. This range keeps the rhizomes dormant without the risk of freezing or premature sprouting.
Temperature for Curing: The First Step
Before you settle your cannas into their long-term winter home, they need a short period of higher temperatures. This process is called curing. Curing allows the outer "skin" of the rhizome to toughen up and any small nicks from the digging process to heal over.
After you have dug up your cannas and gently cleaned off the excess soil, move them to a well-ventilated area where the temperature stays between 70°F and 80°F. This might be a garage, a shed, or even a spare room in your home. Let them sit in this warm spot for about seven days.
This curing phase is vital because it helps the rhizome resist rot and disease during the months of storage. It also allows any remaining moisture on the surface of the plant to evaporate. Storing "wet" rhizomes in a cool environment is a recipe for mold, so this week of warmth is a simple way to set yourself up for success.
How to Prepare Canna Rhizomes for Storage
Proper storage starts with how you handle the plants at the end of the season. At us, we believe that timing and gentle handling make all the difference. You don't need to rush the process; in fact, waiting for the right signals from nature will result in healthier plants.
Digging and Cleaning
The best time to dig your cannas is shortly after the first light frost has turned the foliage brown or black. This frost serves as a natural signal to the plant that it is time to move its energy down into the roots for winter. Once the leaves have withered, cut the stalks down to about 2 to 4 inches above the ground.
When you are ready to dig, use a garden fork or a shovel and start several inches away from the base of the plant. Canna rhizomes can spread quite wide, and you want to avoid slicing through them. Gently lift the entire clump out of the soil. Shake off the loose dirt, but don't feel the need to scrub them perfectly clean. A little bit of dry soil won't hurt, but deep scratches can invite rot.
Air-Drying and Toughening
Once the clumps are out of the ground, move them to your curing area. Lay them out in a single layer so air can circulate around each piece. After the seven-day curing period at 70°F to 80°F, you can trim off any remaining dried roots or long stalks. If the clumps are very large and unwieldy, you can gently break them into smaller sections, making sure each section has at least one or two "eyes" or growth points.
What to do next:
- Wait for the first frost to blacken the leaves.
- Cut the stems to a few inches above the soil line.
- Carefully lift the rhizomes with a garden fork.
- Cure the rhizomes in a warm, dry spot for one week.
Choosing the Best Storage Medium
Once your cannas are cured and the temperature in your storage area is confirmed, it is time to pack them away. You should not simply leave the rhizomes exposed to the air all winter, as they can dry out too much and become shriveled. On the other hand, you don't want them to stay damp.
The goal is to provide a "buffer" that maintains a tiny bit of moisture while allowing the plant to breathe. Common materials for this include:
- Peat Moss: This is a classic choice because it holds just enough moisture to keep the rhizome plump without being wet.
- Vermiculite: This mineral provides excellent aeration and moisture control.
- Sawdust or Wood Shavings: These are easy to find and work well, though you should avoid shavings from treated lumber.
- Newspaper: Wrapping individual rhizomes in several layers of dry newspaper is a simple, effective method for small collections.
Place a layer of your chosen medium in a cardboard box, plastic bin (with the lid left cracked open), or a breathable mesh bag. Lay the rhizomes on top so they aren't touching each other, then cover them with more of the medium. This separation prevents a single bad rhizome from spreading rot to its neighbors.
Key Takeaway: Use a packing medium like peat moss or vermiculite to keep your rhizomes from drying out. Store them in a way that allows for some air circulation to prevent mold.
Finding the Perfect Spot in Your Home
Every home has different microclimates. Finding the right spot for your cannas might require a little bit of exploration. Since you now know that the goal is a dark, cool spot between 40°F and 55°F, you can evaluate different areas.
The Basement
A basement is often the most reliable spot. If your basement is finished and heated, look for a utility room or a corner far away from the furnace. If it is unfinished, it is likely already at the perfect temperature. Avoid placing the boxes directly on a concrete floor, as the floor can sometimes get much colder than the air. Placing the box on a shelf or a wooden pallet is a smart move.
The Attached Garage
Attached garages are great because they benefit from the heat of the house but usually stay much cooler than the living quarters. The best spot is usually against the wall that shares a side with the house. However, be careful if you live in a region with extremely harsh winters. If the temperature in the garage drops below freezing for an extended period, your cannas will need extra insulation or a move to a warmer spot.
Closets and Crawl Spaces
In warmer zones, like Zone 7, an unheated closet on the north side of the house might stay cool enough. Crawl spaces under the home can also be excellent, provided they are dry and protected from rodents.
Storing Cannas in Containers
If you grow your cannas in large pots or decorative containers, you have a shortcut available to you. You don't necessarily have to dig the rhizomes out of the soil. This is often called the "lazy gardener" method, and it works surprisingly well.
Once the frost has hit and you’ve cut back the foliage, simply move the entire pot into your cool storage area. The soil in the pot acts as a natural insulator for the rhizomes. You don't need to water the pot at all during the winter; you want the soil to stay dry so the plant remains dormant.
In the spring, about six weeks before the last frost, you can move the pot back into a warm, sunny spot and begin watering it to wake the plants up. If you want more container advice, see our How Many Canna Bulbs Per Pot? guide. This method is a great time-saver if you have the space to store large containers.
Checking Your Rhizomes Throughout the Winter
Gardening doesn't completely stop in the winter; it just moves indoors. It is a good habit to check on your stored canna bulbs about once a month. This small effort can save your entire collection.
When you check them, look for two things: rot and excessive drying.
- If you see rot: If a rhizome feels soft or mushy, or if you see fuzzy mold growing, remove that piece immediately. If the rot is only on a small tip, you can sometimes cut it off and let the healthy part dry out. Discard any completely rotten pieces so they don't infect the rest of the box.
- If they look shriveled: If the rhizomes look very wrinkled and feel light or brittle, they are getting too dry. Use a spray bottle to lightly mist the packing medium with water. You don't want the medium to be "wet," just slightly damp to the touch. This will provide enough humidity to keep the rhizomes plump.
Most gardeners find that they lose a small percentage of their bulbs over the winter. Don't be discouraged if one or two don't make it; it’s a normal part of the process. If you find that the majority of your bulbs are struggling, it is a sign that you might need to adjust the temperature or the moisture level of your storage spot for next year.
Winter Care Checklist:
- Check storage boxes once a month.
- Remove any rhizomes that feel soft or show signs of mold.
- Lightly mist the packing material if rhizomes appear shriveled.
- Confirm the temperature remains between 40°F and 55°F during cold snaps.
Transitioning Cannas in the Spring
As the days get longer and the ground begins to warm, it’s time to think about bringing your cannas back to life. You don't want to move them directly from a 45°F basement into the garden if there is still a risk of frost.
About four to six weeks before your area’s average last frost date, you can "pre-start" your cannas indoors. This gives you a head start on the growing season, which is especially helpful in northern states where the summer is short. Move the rhizomes into a warmer room (65°F to 70°F) and plant them in pots with moist potting soil. Place them in a sunny window or under grow lights. If you want a deeper look at planting depth, read our How Deep for Canna Bulbs? guide.
By the time the weather is consistently warm and the soil outside has reached about 60°F, you will have healthy, sprouted plants ready to go into the ground. If you prefer a simpler approach, you can wait until the danger of frost has passed and plant the dormant rhizomes directly into the garden. Just remember that it will take a few weeks for them to poke their heads above the soil.
At Longfield Gardens, we always recommend checking your local weather patterns. Nature is unpredictable, so it is better to wait an extra week for warm soil than to rush and have your plants struggle in the cold mud.
Conclusion
Storing canna rhizomes is a simple and rewarding way to keep your garden glowing year after year. By focusing on the correct temperature—keeping things between 40°F and 55°F—you provide the perfect environment for these tropical beauties to rest. Whether you choose to store them in peat moss in the basement or leave them in their summer pots in a cool garage, the effort you put in now will pay off with a spectacular display next summer.
- Wait for the first frost to signal dormancy before digging.
- Cure rhizomes for a week at 70-80°F before packing them away.
- Store in a cool, dark, and dry location to prevent premature growth or rot.
- Perform a quick monthly check to ensure they stay healthy through the winter.
Overwintering your plants is a great way to grow your garden without extra cost. With a little bit of care and the right storage conditions, your cannas will be ready to transform your yard into a tropical retreat once again. If you are ready to expand your collection, we invite you to browse our selection of premium Canna Assorted Collection and Tall Cannas at Longfield Gardens.
"Finding the right balance of temperature and moisture is the secret to a successful winter storage routine for all tender garden bulbs."
FAQ
Can I store canna bulbs in a refrigerator?
It is usually not recommended to store canna rhizomes in a kitchen refrigerator. Refrigerators are often kept at 35°F to 38°F, which is slightly too cold for cannas and can lead to tissue damage. Additionally, refrigerators have very low humidity, which can cause the rhizomes to dry out and shrivel quickly. For shipping and timing details, review our Shipping Information before you plan your order.
What happens if the storage temperature drops below 32°F?
If the temperature falls below freezing, the water inside the fleshy rhizome will freeze and expand. This causes the cell walls to burst, effectively killing the plant. Once a rhizome has frozen, it will become mushy and black when it thaws, and it will no longer be viable for planting in the spring.
How can I tell if my storage spot is the right temperature?
The most reliable way is to use a simple indoor/outdoor thermometer or a "min-max" thermometer. Place it in your chosen storage spot for a few days during a cold spell. This will tell you exactly how low the temperature gets at night, ensuring it stays within the safe 40°F to 55°F window. If you want a broader climate reference, check the Hardiness Zone Map.
Should I water my cannas while they are in storage?
In most cases, you should not water them. The goal is to keep the rhizomes dormant and dry enough to prevent rot. However, if you notice the rhizomes are looking extremely shriveled during your monthly check, you can very lightly mist the packing medium (like peat moss) to add a tiny bit of humidity back into the box. If you want more seasonal guidance, see How to Overwinter Canna Bulbs and How to Winterize Canna Bulbs.