Spring Tulip Displays Start Now
If you want big blooms that last more than one season, you’ll need to dig deep
This is bulb-planting time. But if you plant tulips following the package instructions, the plant will reach its full potential only in the first year. That’s because those instructions were written for growing tulips in cooler regions. Here in Southern Maryland, tulip bulbs should be planted at least two inches deeper than recommended by the distributors.
Tulips are perennials, but when planted only six inches deep in our soils, they will only flower well the first year. If you leave them in the ground a second year, the flowers will generally be smaller and the plantings will degenerate. This is because the soil warms quickly in the spring, resulting in higher oxygen levels in the upper layer and promoting the production of daughter bulbs instead of promoting the growth of the mother bulb.
Bulb growers in the Netherlands and in Michigan utilize this knowledge for producing daughter bulbs and for growing large bulbs for sale. Since larger bulbs produce larger flowers and larger bulbs sell for a higher price, it behooves bulb growers to grow larger bulbs and make more money.
To propagate tulip bulbs, growers plant the mother bulbs only three to four inches deep. To produce high-quality large bulbs for market, growers plant the daughter bulbs eight to 10 inches deep. The deeper the bulb is planted, the cooler the soil and the lower the oxygen level. Both discourage the bulbs from multiplying, thus forcing them to grow larger. To produce extra-large tulip bulbs, growers leave them in the ground through a second growing season.
I prefer planting tulip bulbs in circular clumps rather than in rows. Clumping makes maximum use of a limited number of bulbs. Position the flat side of each bulb against the outside wall of the planting hole.
Dig a hole 12 to 14 inches in diameter and 10 to 12 inches deep. The walls of the hole should be smooth and perpendicular. In the bottom of the planting hole, place a two- to four-inch layer of compost and thoroughly incorporate it into the soil in the bottom of the hole. Press each bulb one to two inches around the edge, and in the middle place two bulbs about an inch apart with the rounded part of each bulb toward the other.
Mix the excavated soils with one-third by volume of compost before filling the hole. When the planting hole is about two-thirds full, flood it with water to properly compress the amended soil around each bulb.
Leaves of bulbs planted with the flat side against the hole wall will bend outward, resulting in larger looking clumps. This technique is used by commercial growers who flower potted tulip bulbs for Easter.
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