Dahlias on balconies and terraces can overwinter very well in pots. This guide has all the information you need on how to prepare dahlia bulbs for winter, store them properly and overwinter them without digging them up. Care tips explain how to start the new season successfully.
How can you overwinter dahlia bulbs in a pot?
To overwinter dahlia bulbs in pots, stop fertilizing from September onwards, water less in October and cut off dead plant parts after the first frost. Store the pots in a frost-free, dark room at 5° to 8° Celsius.
Preparation begins in September
Preparations for dahlias to overwinter in pots begin in October. By stopping nutrient supply and reducing water supply, you prepare dahlia bulbs for the upcoming winter. How to do it right:
- Beginning/mid September: Stop fertilizing dahlias
- Beginning/mid October: water more sparingly, but do not let the soil dry out
Please continue with this modified care until the first frost.
Putting away dahlia bulbs – How to do it right
After the first few nights of frosty temperatures, dahlias wilt in the pot. This is the signal to move into winter quarters. Here's how to do it without digging:
- Cut off dead dahlias until they are hand-width above the pot substrate
- Dispose of clippings in the compost or in organic waste
- Don't dig up dahlia bulbs
- Place the pot in a frost-free, dark room with temperatures of 5° to 8° Celsius
Windowless, cool basement rooms are ideal for winter quarters. Alternatively, dahlia bulbs can overwinter in a dark garage or in a shady spot in the storage room. Temperatures well below 10° Celsius are the most important requirement for dahlia bulbs in pots. Otherwise the tubers will sprout far too early, exhaust themselves completely in the darkness and deny the hoped-for flower festival next year.
Overwintering dahlia bulbs in pots – care tips
Care is reduced to a minimum when dahlia bulbs overwinter in pots. Cool, dark conditions cause the tubers to grow dormant for months. However, you shouldn't completely ignore your winter guests. Regular checks and a change of location at the end of February set the course for a season full of flowers:
- Check dahlia bulbs regularly for premature sprouting
- Monitor temperatures and, if necessary, relocate to a cooler winter location
- Repot dahlia bulbs into fresh, loose substrate from the end of February/beginning of March
- Change location to the bright window sill in a temperature-controlled room with 10° to 15° Celsius
Dahlia bulbs come to life in a bright, cool location. Water very sparingly in the first few weeks. Start fertilizing in mid-April.
Tip
If there is a lack of space in your winter quarters, you can stack dahlia bulbs in a large, airy container. Fill a layer of peat sand into a wooden box lined with newspaper, place prepared dahlia tubers on top at a distance of 2-3 cm and cover the bulbs completely with substrate. You can overwinter additional tubers on this substrate layer.
