Dahlias, with their dazzling colors and intricate blooms, are the highlight of many gardens. From late summer until the first frost, these flowers put on a spectacular show. But to ensure a bountiful display year after year, it’s essential to care for the tubers properly as the seasons change. In this guide, we’ll explore why digging up, dividing, and storing your dahlia tubers is crucial and provide step-by-step instructions to make the process simple and effective.
Why Do You Need to Dig and Store Dahlia Tubers?
Dahlias are tuberous plants, which means they store nutrients in underground tubers. In colder climates, dahlias can’t survive frost if left in the ground; the freezing temperatures damage their tubers, preventing regrowth in the following year. Digging up and storing your dahlia tubers allows you to:
- Protect them from frost: Tubers left in the ground during winter may rot or freeze, ending the plant’s life cycle.
- Divide and propagate: Dividing tubers lets you multiply your dahlia collection without purchasing new plants.
- Manage growth and vigor: Dividing tubers helps control the plant size and maintains the vitality of each plant, ensuring healthier, more vigorous blooms.
Here’s a complete, step-by-step guide to digging, dividing, and storing dahlia tubers to keep them in prime condition for replanting.
Step 1: Wait for the First Frost
The first frost will naturally signal the end of the dahlia’s growing season by causing the foliage to wilt and turn brown. Frost is crucial because it triggers the tubers to go dormant, readying them for winter storage. Once you see signs of the plant “dying back,” wait a few days before digging to ensure the plant’s energy has moved fully into the tubers.
Note: In warmer climates, where frost doesn’t naturally occur, allow the plants to reach the end of their season or when growth naturally slows.
Step 2: Cut Back the Stems
Once the foliage has died back, cut the stems to about 4-6 inches above the ground. This trimming makes it easier to lift the tubers and handle them without damaging them. Use clean, sharp pruners to avoid introducing disease or tearing the stems.
Step 3: Dig Up the Tubers
Using a garden fork or shovel, carefully dig around the base of each dahlia plant, starting several inches away from the stem. Dahlia tubers are fragile and can be easily damaged, so work gently, lifting the soil to loosen and lift the tuber clump. Carefully pull the entire root system from the ground, doing your best to avoid breaking or bruising the tubers.
Step 4: Clean the Tubers
Shake off excess soil, but avoid rough handling. Lightly rinse the tubers with water to remove any remaining dirt. Allow them to air-dry, placing them in a shaded, cool area for a day or two. Proper drying reduces the risk of mold and rot, keeping the tubers healthy through winter.
Step 5: Identify and Mark “Eyes”
Eyes are the small buds on each tuber where new growth will emerge in spring. These eyes may be small and difficult to see at first. Sometimes, setting the tubers aside for a day or two helps make the eyes more noticeable as they begin to “pop.” If you’re planning to divide the tubers, make sure each section you cut has at least one eye—this is essential for growth.
Step 6: Divide the Tubers
Dividing your dahlia tubers encourages better growth and gives you the added benefit of propagating more plants. Using a sharp, sterilized knife, separate each tuber from the main clump. Make sure each section contains an eye, as well as a portion of the original stalk or “neck,” which holds the nutrients the plant needs to grow.
Tip: Some gardeners choose to leave the tubers undivided until spring to make the eyes easier to identify.
Step 7: Cure the Tubers
After division, curing the tubers is essential. Place them in a dry, well-ventilated area out of direct sunlight. Curing allows the tuber skins to toughen, which helps prevent rot and disease. Curing should take 1-2 weeks. Afterward, you’ll notice the tubers feel slightly firmer and have developed a protective skin.
Step 8: Prepare for Storage
Once cured, your tubers are ready for storage. Choose a storage container that allows some air circulation, like a cardboard box or wooden crate. Line the container with peat moss, vermiculite, or sawdust, which will insulate the tubers and help prevent them from drying out. Nestle each tuber carefully, ensuring they are not touching to minimize the risk of mold or rot spreading.
Step 9: Store in a Cool, Dark Place
Find a storage area that stays cool and dark through winter, ideally at 40-50°F. Basements, garages, or crawl spaces often work well. Extreme cold or heat can damage the tubers, so aim for a consistent temperature. Check on your tubers every few weeks to ensure they’re not drying out or rotting. If they look shriveled, lightly mist the packing material.
Step 10: Inspect and Replant in Spring
As the growing season approaches, take your tubers out of storage to inspect them. Remove any that have become soft or moldy, and give the healthy tubers time to “wake up” by moving them to a slightly warmer area. Once the danger of frost has passed, you can plant your dahlia tubers in your garden or containers to enjoy another season of beautiful blooms.
Additional Tips for Successful Dahlia Care
- Labeling: Label each tuber variety to keep track of different colors and types.
- Spacing: When planting, give dahlias ample space, as they thrive with good air circulation.
- Mulching: Adding mulch in spring helps conserve moisture and prevent weeds.
Common Issues and Solutions
- Rot: Prevent rot by ensuring tubers are properly cured and not stored in overly moist conditions.
- Fungal Diseases: Treat any visible mold on tubers with a fungicide before storing.
- Temperature Swings: Maintain a consistent storage temperature to avoid stressing the tubers.
Conclusion
Digging, dividing, and storing dahlia tubers may take a bit of time, but the reward of healthy, vibrant dahlias blooming in your garden year after year makes it worthwhile. By following these steps, you’ll not only protect your dahlia plants but also expand your collection, as each divided tuber can grow into a stunning new plant. Share your dahlia care tips, photos, and experiences with fellow gardening enthusiasts!