Why Planting Bulbs Need to Be Thinned

Overcrowding

• When bulbs begin to flower less, or the blossoms become smaller and weaker, the plants are likely overcrowded. As the bulbs reproduce beneath the soil surface, more plants begin competing for nutrients, water and sunlight. Eventually this weakens the bulbs and the blossoms become weak or stop completely. Digging up and thinning the bulbs allows you to replant them at optimum spacing so all the plants receive the water and nutrients they need.

Propagation

• Most bulb plants produce new bulbs, called bulblets. The bulblets grow attached to one of the mature bulbs, or mothers, until they are large enough to produce a plant on their own. Remove the bulblets from the mothers when you thin the bulbs, as they provide you with new, free bulbs to plant in new beds. Twist the bulblets gently to snap them off the mother bulb. They have the same cultural requirements as the mother bulbs. Depending on their size, they may not flower the first year, but they will produce foliage that grow into a mature bulb by the following year.

Disease Prevention

• Bulbs are resistant to most diseases, but rot from too much moisture, or can develop fungus. Dispose of any bulbs that have soft spots or that appear shriveled, as these are infected with disease that can spread to nearby healthy bulbs. Thinning regularly allows you to inspect the bulbs and stop a disease problem before it begins.

Age Management

• If bulbs do not flower for two years in a row, it's likely the bulb has aged and weakened to a point where it will no longer be productive. Thin out these unproductive bulbs and replace them with new, fresh bulbs so that the garden bed remains in full bloom each year. While some bulbs, like daffodils, bloom for many years, others like tulips only flower for two to three years before they become to old to bloom well.