The ability to plant bulbs now depends entirely on the bulb type and the current season. A bulb is a plant’s underground storage organ, containing food reserves and a miniature flower bud, allowing it to survive dormancy. While planting is straightforward, successful blooming requires planting at the correct time. Ensuring ideal temperature and moisture levels for root development is the most important factor for a vibrant display.
Understanding Bulb Types and Ideal Planting Seasons
Flower bulbs are divided into two categories based on their required planting time and natural flowering season. This division is determined by the specific environmental conditions each type needs to break dormancy and initiate flowering. Planting the correct type of bulb at the appropriate time ensures a successful bloom cycle.
Spring-flowering bulbs, such as tulips, daffodils, and hyacinths, must be planted in the fall, typically from late September to November. These “hardy” bulbs require a prolonged period of cold, called vernalization, which triggers flower development. Planting them in the cooling soil of autumn allows them to establish a robust root system before the ground freezes, enabling them to bloom when temperatures rise.
Conversely, summer-flowering bulbs, including dahlias, gladiolus, and canna lilies, are planted in the spring. These “tender” bulbs cannot tolerate freezing temperatures, so they should only be placed in the ground once the danger of the last hard frost has passed. Planting them in late spring allows them to establish quickly in warm soil and produce blooms throughout the summer and into early fall.
Preparing the Site and Planting Techniques
Successful bulb planting requires a location that offers excellent drainage, as bulbs quickly rot in wet soil. Integrating organic matter, such as compost or well-rotted manure, improves soil structure and facilitates water percolation away from the bulb. While fertilizer is not necessary at planting time, mixing in bone meal provides a slow-release source of phosphorus to support root growth.
The general rule for planting depth is to bury the bulb two to three times its height, measured from the base to the tip. For example, a two-inch tall daffodil bulb should be planted between four and six inches deep. Planting at the proper depth stabilizes the bulb, regulates soil temperature, and provides protection from cold and digging animals.
Bulbs should be placed in the hole with the pointed end facing upward, where the flower shoot emerges, and the flatter basal plate facing down, where the roots form. A good spacing guideline is to leave a distance of at least two to three bulb-widths between each one to prevent overcrowding. After covering the bulbs with soil, water them thoroughly to eliminate air pockets and settle the surrounding earth.
Temporary Storage and Troubleshooting
If the planting window has closed, or if conditions like frozen or waterlogged soil are unfavorable, temporary storage is necessary to preserve the bulb’s viability. Bulbs must be kept dormant until conditions are right for planting. The best storage environment is a cool, dry, dark, and well-ventilated space, such as a basement, garage, or refrigerator.
Ideal storage temperatures range from 50 to 60 degrees Fahrenheit for many bulb types, though some require cooler conditions. Bulbs should be stored in a breathable container, like a paper bag, cardboard box, or mesh sack, and never sealed in plastic, which traps moisture and encourages rot. Surrounding the bulbs with a dry material like peat moss, vermiculite, or sawdust helps maintain moisture levels and prevents contact between individual bulbs, which can spread decay.
For spring-flowering bulbs that missed the fall deadline, one strategy is to “pot up” the bulbs in containers and place them in a protected, unheated area for cold treatment. This allows them to develop roots and undergo vernalization before being moved to an outdoor display area in the spring. This approach prevents the bulb from rotting if the ground is too wet or from freezing if planted too late.