Just till two inches for tulip bulbs, study finds
October 27, 2011 —
REGION — A Cornell University study shows that “top planting” is a much easier method of planting tulip bulbs and just as effective as digging the traditional six- to eight-inch holes for each bulb.
To top plant: Till the soil about two inches deep, place the bulbs on top of the soil and then cover them with a two-to-four inch layer of mulch and water to achieve successful tulips that will thrive year after year. No strenuous digging is needed.
“Top planting is a good way to go,” said William B. Miller, professor of horticulture and director of Cornell’s Flower Bulb Research Program.
Top planting is an old, yet underused method. Miller’s three-year study of the process demonstrated that it definitely works. He used this method to plant “Ad Rem” and “Negrita” tulip cultivars, which are known as good perennializers, in plots testing four different depths of mulch. Bulbs that were covered with two to four inches of mulch yielded the most flowers in 2009, 2010 and 2011. In the study, a slow-release fertilizer was used, which Miller recommends.
Optimum planting in Central New York is from mid- to late September through mid November. Bulbs root readily as long as soil temperatures are in the range of 40-50 degrees Fahrenheit. Visit blogs.cornell.edu/hort/2011/07/07/top-planting-tulips-cuts-labor.