It’s hard to imagine preparing for another garden season as the summer growth is barely behind us. However, now is the time to get our bulbs ready for the spring. For some species that means it’s time to plant and for others it’s time to pull them out of the ground. Here are some tips for getting it right and having a beautiful spring and summer flower garden.
How do you know whether bulbs should be planted in the fall or spring? Bulbs are categorized as either tender or hardy. Tender bulbs should be planted in the spring for summer blooming, while hardy bulbs should be planted in the fall for spring blooms. Examples of tender bulbs include: Amaryllis, Canna, Gladiolus, Begonia and Caladium. Examples of hardy bulbs include: tulips (Tulipa sp.), daffodils (Narcissus sp.), hyacinth (Hyacinthus sp.), Crocus, Allium, Fritillaria, grape hyacinth (Muscari sp.).
Why do bulbs need to be planted in the fall if they aren’t going to bloom until spring? Hardy bulbs require a chilling period, which should ideally be at least 10 to 13 weeks with temperatures below 40 degrees Farhenheit. Planting the bulbs in the fall, before the ground freezes, allows time for roots to develop giving the plant a better chance at healthy growth.
Can you still plant hardy bulbs if you miss the fall planting period? If you plant the bulbs in spring, they likely will not flower. However, if you save them for the next fall, the bulbs are likely to become soft and rot while in storage. Additionally, the food supply stored in the bulbs will start to deplete during the time they are out of the soil. One solution is to plant the bulbs as soon as the soil thaws. There will still be days of cold temperatures so the bulbs will still get some chilling period. Though the bulbs will likely not bloom in the spring, they may bloom during the summer.
Another option is to create an artificial chilling period. Plant the bulbs in containers and keep them in a refrigerator or other space that is below 40 degrees Fahrenheit for the required 10 to 13 weeks. After that time, move the containers to a location where it is 65 to 70 degrees F. This change imitates the spring temperatures and the bulbs will bloom within a few weeks.
What do I do with tender bulbs in the fall? Tender bulbs should be dug up once the foliage dies back. Take care not to damage the roots as you dig and remove the soil. Care for the bulbs varies depending on the species. Dahlias and Cannas can be washed and dried, whereas Gladiolus should not be washed. Dry the bulbs in a dark room where temperatures are between 60 and 70 degrees. After a few weeks the bulbs can be labeled and stored in a cool, dry room until the temperatures outdoor are warm enough for planting in the ground.
Where is a good spot to plant bulbs outdoors? Sandy loam soil is best for bulbs, but any soil will suffice if you mix in compost. Healthy soil allows for proper drainage which prevents the bulbs from rotting. Choose a location that receives full to part sun. Be sure to follow the planting recommendations for the specific plant type. Typically, smaller bulbs should be planted shallower. Also consider the arrangement of the bulbs for the most attractive spring display.
One final tip is to make a garden map so you remember where you planted your hardy bulbs and where you plan on incorporating the tender bulbs after the cold season. A little planning will go a long way for next year’s garden.
Cynthia Domenghini is an instructor and coordinator for K-State’s horticultural therapy online certificate program.