Gladiolus bulbs (corms) should generally be planted about 4 to 6 inches (10 to 15 cm) deep. The exact depth depends on the size of the corm:
- Large corms: 4 to 6 inches deep
- Medium-sized corms: 3 to 4 inches deep
- Small corms: 2 to 3 inches deep
Planting deeper (around 6 inches) helps support the tall flower spikes and prevents the plants from falling over. On sandy soils, planting slightly deeper can improve stability. It is important not to plant too shallowly, as this can cause the production of many small offspring corms instead of a strong main corm for the next year
. When planting, place the corm upright with the pointed side facing up and space them about 3 to 6 inches apart, depending on the variety and planting method. For rows or trenches, spacing around 6 inches apart is common. In containers, corms can be planted closer together but still deep enough to ensure stability
. In summary, aim for about 4 to 6 inches deep for most gladiolus bulbs, adjusting slightly based on corm size and soil type to ensure healthy growth and strong flowering stems.
