Introduction
There is nothing quite like the sight of a tuberous begonia in full bloom. Whether they are cascading from a hanging basket or brightening a shady corner of your porch, these plants are known for their spectacular, rose-like flowers and lush foliage. At Longfield Gardens, we believe that the joy of growing these tropical beauties should not end when the first frost arrives. Because tuberous begonias grow from a thick, energy-storing root called a tuber, they can be saved and enjoyed for many years.
Many gardeners ask us: can you leave begonias in pots over winter? The answer is yes! If you are growing tuberous begonias, they can successfully stay in their original containers through the winter months. Instead of treating them as annuals that must be replaced each spring, you can help them enter a period of rest known as dormancy. This article will guide you through the straightforward process of how to overwinter tuberous begonias, ensuring your favorite varieties return even bigger and better next season. By following a few basic steps, you can successfully preserve your plants and look forward to another summer of vibrant color. For a broader look at tuberous begonia types and care, see our All About Begonias guide.
Understanding Tuberous Begonias and Dormancy
Before you begin the overwintering process, it is helpful to understand how these plants function. Tuberous begonias, such as the popular Begonia Nonstop Mix, are native to the high-altitude forests of South America. Technically known as Begonia × tuberhybrida, these plants—including the popular trailing species Begonia boliviensis—have evolved to handle distinct seasons. During the warm, moist summer, they produce beautiful flowers. When the days grow shorter and the air turns cool, the plant prepares for a period of deep sleep.
This sleep, or dormancy, is a vital part of the begonia’s lifecycle. The plant pulls all its energy from the leaves and stems down into the tuber. This tuber acts like a battery, storing everything the plant needs to sprout again in the spring. If you live in a region where the ground freezes, these tubers cannot survive outdoors. However, according to experts at the American Begonia Society and the RHS, they are perfectly happy spending the winter in a cool, dry spot inside your home.
It is important to distinguish tuberous begonias from other types, like wax begonias or Rex begonias. Wax begonias have fibrous roots and do not go dormant; they are typically grown as year-round houseplants. Tuberous begonias, on the other hand, require a rest period to stay healthy and productive. If you see a thick, potato-like root at the base of your plant, you have a tuberous begonia ready for winter storage.
Preparing Your Potted Begonias for Winter
Success starts with timing. You want to let your begonias enjoy the outdoors for as long as possible, as this allows the tuber to grow to its maximum size. A larger tuber typically produces a more vigorous plant with more flowers the following year. However, you must act before a hard, killing frost hits.
In late summer or early fall, you will notice the plant’s growth slowing down. The flowers may become smaller or less frequent. This is your signal to begin the transition. Start by reducing the amount of water you give the plant. Instead of keeping the soil consistently moist, let it dry out more than usual between waterings. This encourages the plant to start moving its resources down into the tuber.
Before moving them into storage, we recommend a quick sanitation check. Inspect the foliage and the base of the stems for signs of pests or fungal disease. Remove any fallen leaves or spent blooms from the soil surface to prevent rot. Additionally, ensure your storage area is secure from rodents, as mice sometimes find dormant tubers to be an appealing winter snack.
As the nights get cooler, the foliage will naturally begin to yellow or wilt. This is a good sign! It means the plant is entering its natural rest phase. We recommend waiting until the first light frost nipped the leaves or until the foliage has mostly turned yellow before moving the pots to a sheltered area like a porch or garage. For more guidance on timing, see Shipping Information.
Key Takeaway: Tuberous begonias need a rest period to thrive. Start reducing water in late summer to signal to the plant that it is time to store energy for the winter.
Choosing Between Pot Storage and Lifting
When deciding how to overwinter tuberous begonias, you have two primary choices: leave them in their pots or lift the tubers out of the soil.
- Choose pot storage if: You have the space, you want the easiest method possible, and the soil is healthy and pest-free.
- Choose lifting if: You have many plants and limited storage space, you want to divide the tubers, or you need to inspect the tubers closely for signs of rot or disease.
Option 1: Storing Begonias Directly in Their Pots
One of the easiest ways to overwinter tuberous begonias is to keep them right in the containers they grew in all summer. This method is excellent for busy gardeners because it minimizes the work of digging and cleaning tubers. It also protects the tuber from physical damage during the transition.
Drying Out the Soil
The most important rule for overwintering in pots is that the soil must be completely dry. If the soil stays damp during the winter, the tuber is likely to rot. Once you have moved your pots to a dry, frost-free location, stop watering them entirely. If the pots are large, it may take several weeks for the root ball to dry out completely.
Removing the Old Foliage
As the stems and leaves dry out, they will eventually pull away from the tuber with a gentle tug. Do not force the stems off while they are still green and firmly attached. Breaking a green stem can create a wound that allows rot to enter the tuber. Wait until the stems are brittle or have turned mushy and detached naturally. Once the foliage is gone, you can clear any debris from the surface of the soil.
Storing the Containers
Place the dry pots in a cool, dark, and dry location. A basement, unheated closet, or an insulated crawl space is often ideal. The temperature should stay between 40°F and 50°F. If the area is too warm, the tuber might try to sprout too early. If it gets below freezing, the tuber will be damaged. To ensure they stay dry, some gardeners tip the pots on their sides. This prevents accidental watering or drips from reaching the soil.
- Move pots to a dry area before the first hard freeze.
- Stop watering immediately to allow the soil to dry out.
- Wait for foliage to detach naturally before removing it.
- Choose a cool, dark spot that stays above freezing but below 55°F.
Option 2: Lifting Tubers from the Soil
While storing begonias in pots is convenient, some gardeners prefer to "lift" the tubers. This involves removing them from the soil and storing them in a smaller space. This is a great option if you have many plants and limited storage room, or if you want to inspect each tuber for health.
Digging and Curing
Gently lift the tuber and its surrounding root ball out of the pot. Be careful not to nick the skin of the tuber with your tools. Use your hands to brush away the bulk of the soil. You do not need to wash the tuber; in fact, keeping it dry is better.
Next, the tubers need to "cure." Place them on a tray or a piece of newspaper in a warm, dry room out of direct sunlight. Let them sit for about one to two weeks. During this time, the outer skin will toughen up, and any remaining soil will become dry and easy to brush off. This curing process is essential for preventing rot during the long winter months.
Packing for the Winter
Once the tubers are cured and clean, you can pack them away. Use a breathable container like a cardboard box or a paper bag. To keep the tubers from touching each other and to maintain a very slight amount of humidity, nestle them into a bedding material. We find that peat moss, perlite, vermiculite, or even dry sawdust works well. This packing material acts as insulation against temperature changes and prevents the tubers from shriveling up completely.
Key Takeaway: Lifting and curing tubers is the best method if you are short on space. Always allow the tubers to dry for at least a week before packing them in breathable material like peat moss.
Choosing the Best Indoor Storage Location
The environment where you store your begonias will determine how well they survive the winter. Think of the storage spot as a refrigerator for your plants—it should be cool and stable.
Temperature Matters
The "sweet spot" for begonia storage is between 40°F and 50°F. Most modern homes are too warm for dormant plants. A heated living room will cause the tubers to lose moisture and shrivel. Conversely, an unheated shed might drop below freezing, which will turn the tubers to mush. An attached garage that stays cool but frost-free, a root cellar, or a cool corner of a basement are usually the best choices.
Humidity and Light
The storage area should be dark. Light is a signal for plants to grow, and you want your begonias to stay asleep until spring. Humidity should be low to moderate. If the air is too damp, mold and rot become a risk. If the air is extremely dry, you may notice the tubers starting to look wrinkled. If they seem excessively dry, a very light misting of the packing material (not the tuber itself) once or twice during the winter can help.
Checking Your Tubers During the Winter
Gardening in the winter is mostly about observation. Even though your begonias are dormant, it is a good idea to check on them about once a month. This simple habit allows you to catch any potential issues before they become problems.
Troubleshooting Winter Storage Issues
During your monthly checks, you may encounter a few common issues. Here is how to handle them:
- Mushy or Soft Spots: This is a sign of rot. If the rot is widespread, discard the tuber to prevent it from spreading to others. If it is a small spot, you can try cutting it out with a clean knife and letting the area dry.
- Excessive Shriveling: If the tuber looks like a raisin, it is losing too much moisture. Mist the packing material (peat moss or vermiculite) lightly with water. Do not wet the tuber itself.
- Surface Mold: Fuzzy white or grey mold indicates the air is too damp. Increase airflow and brush off the mold.
- Premature Sprouting: If you see pale shoots in January or February, your storage area is likely too warm or bright. Move the plants to a cooler, darker spot to keep them dormant longer.
If you are storing your begonias in pots, check that the soil remains bone-dry. Sometimes, a humid basement can cause the soil to hold onto moisture. If the soil feels damp, move the pot to a location with better circulation. For more watering and care tips, see Will Begonias Grow in the Shade? Best Tips for Low Light.
- Set a monthly reminder to peek at your stored tubers.
- Remove any tubers that feel soft or show significant mold.
- Adjust the humidity if tubers look shriveled (too dry) or fuzzy (too damp).
- Ensure the storage area remains dark and within the safe temperature range.
Preparing for the Spring Revival
As the days begin to lengthen in late February or March, you will notice your begonias naturally starting to wake up. This is an exciting time! You might see small pink or white "eyes" or buds beginning to form on the concave (hollowed out) side of the tuber. This is the plant's way of telling you it is ready to grow.
Waking Them Up
To restart your begonias, bring the pots or individual tubers into a warm, bright room. If you stored them in pots, they need a "spring reset." Carefully scrape away the top 2-3 inches of old soil, being careful not to hit the tuber. Replace it with fresh, high-quality potting mix to provide a nutrient boost. If you stored bare tubers, place them in small pots filled with a light, well-draining mix.
The First Watering
The first watering is the most critical. You want to moisten the soil to signal to the roots that it is time to work, but you must avoid overwatering. Too much water before the plant has leaves to use it can cause the tuber to rot. Give them a light drink and then wait until you see green sprouts emerging from the soil before you begin a regular watering schedule.
Providing Light
Once the sprouts appear, begonias need plenty of bright, indirect light. A south-facing window is usually too intense and might scorch the tender new leaves. An east or west-facing window is often perfect. If you do not have enough natural light, a simple grow light can help keep the plants from becoming "leggy" or stretched out. For more on light levels, read Is a Begonia a Shade Plant? Discover Light Needs & Care.
Moving Begonias Back Outdoors
The transition back to the garden should be a gradual one. Tuberous begonias are very sensitive to cold and should not be moved outdoors until the danger of frost has completely passed and the night temperatures are consistently above 50°F.
Hardening Off
The process of "hardening off" involves moving your plants outside for a few hours each day and bringing them back in at night. Start by placing them in a fully shaded, protected spot. Gradually increase their time outside and their exposure to filtered light over the course of seven to ten days. This allows the leaves to toughen up and adapt to the wind and temperature fluctuations of the outdoors.
Choosing the Right Spot
When you are ready to place your pots in their permanent summer home, remember the "Right Plant, Right Place" rule. Tuberous begonias love bright shade. This means a spot that gets plenty of light but is protected from the direct, midday sun. Under a porch roof, beneath a high-canopy tree, or on the north side of a house are all excellent locations. If you want more help choosing the right bed or container, see Where to Plant Begonias for the Best Blooms.
Key Takeaway: Do not rush the move outdoors. Wait until nights are warm, and gradually introduce your plants to the outdoor air through the hardening-off process.
Common Myths About Overwintering Begonias
There is a lot of advice available online, and some of it can be confusing for beginners. Let’s clear up a few common misconceptions about overwintering tuberous begonias in pots.
One common myth is that you must cut the plants back severely before bringing them inside. In reality, it is much better to let the foliage die back naturally. This ensures the tuber has absorbed all the possible nutrients from the leaves. Another myth is that begonias need to be "fed" or fertilized during the winter. Since the plant is dormant and not growing, it cannot use fertilizer. In fact, adding nutrients during dormancy can actually harm the tuber.
Finally, some people believe that you can simply keep tuberous begonias growing as houseplants all winter without a rest. While they might survive for a while, they will eventually become weak, leggy, and prone to pests. Respecting their need for a three to four-month "nap" is the secret to having huge, healthy blooms every summer.
The Rewards of Overwintering
While it might seem like a few extra steps, the rewards of saving your begonia tubers are well worth the effort. As tubers age, they grow larger. A three-year-old tuber can be twice the size of a new one, producing a massive display of flowers that you simply cannot get from a young plant.
At Longfield Gardens, we have seen how satisfying it is for gardeners to see their "old friends" emerge from the soil each spring. It creates a sense of continuity in the garden and saves you money on replacement plants. Plus, as you become more comfortable with the process, you can even begin to divide your larger tubers to create even more plants for your collection.
For a container-friendly option with a trailing habit, browse our Hanging Begonias collection.
Simple Care Tips for Summer Success
Once your overwintered begonias are back in their summer spots, a few simple habits will keep them looking their best until it is time to overwinter them again.
- Watering: Always check the soil before watering. Stick your finger an inch into the soil; if it feels dry, it is time to water. If it is still damp, wait a day. Begonias have succulent stems that store water, so they are more likely to suffer from overwatering than underwatering.
- Feeding: Use a balanced, water-soluble fertilizer every two weeks during the peak growing season. This provides the energy needed for those large, double blooms.
- Grooming: Remove faded flowers (deadheading) to keep the plant looking tidy and to encourage the production of new buds.
- Airflow: Ensure your pots aren't crowded too closely together. Good air circulation helps prevent common issues like powdery mildew. For spacing help, see How Far Apart Do You Plant Begonias? Tips for Lush Growth.
Conclusion
Overwintering tuberous begonias in pots indoors is a rewarding practice that turns a beautiful summer plant into a long-term garden treasure. By understanding the plant's need for dormancy and providing a cool, dry place for it to rest, you can ensure your begonias return with even more vigor each year. Whether you choose to leave them in their pots or lift the tubers for storage, the key is keeping them dry and protected from the frost.
We are here to help you succeed in every season. With a little patience and these simple steps, you will find that overwintering is one of the easiest ways to enhance your garden's beauty year after year.
- Timing is everything: Start the dormancy process in late summer by reducing water.
- Stay dry: Ensure soil or tubers are completely dry before long-term storage.
- Cool and dark: Store your plants between 40°F and 50°F for the best results.
- Patience pays off: Wait for warm nights before moving your begonias back outside in the spring.
Saving your begonia tubers is an easy win for any gardener. It is a simple way to grow larger, more impressive flowers while building a deeper connection with your garden's natural cycles.
We encourage you to give it a try this autumn! For more helpful guides on caring for your favorite plants, visit our Garden Basics page at Longfield Gardens.
FAQ
Can I overwinter wax begonias the same way as tuberous begonias?
No, wax begonias do not have tubers and do not go dormant. If you want to save wax begonias, you must bring them inside as active houseplants and provide them with plenty of light and regular water throughout the winter.
What should I do if my tuber looks shriveled in mid-winter?
A small amount of wrinkling is normal as the tuber loses a little moisture. If it looks very shriveled, you can lightly mist the packing material (like peat moss) with water, but do not soak the tuber itself, as this can cause rot.
When exactly should I bring my potted begonias inside?
You should bring them into a protected area like a garage or porch when night temperatures start dipping into the 40s. Make sure to move them to their final, frost-free indoor storage spot before the first hard freeze occurs in your area. For more timing details, see Find the Best Begonia Growing Zone for Garden Success.
Do I need to fertilize my begonias while they are stored indoors?
No, you should never fertilize dormant begonias. They are not actively growing and cannot process the nutrients. Wait until the plant has sprouted several inches of new growth in the spring before you begin a light fertilization routine.
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