How to grow bulbs

Planting Bulbs: With very few exceptions, bulbs require soil that drains well the year round. To improve the drainage of heavy soil, dig in organic matter such as compost, aged manure, leafmold, peat moss, or (in the South) shredded pine bark. If you garden in very heavy clay, consider constructing raised beds to provide well-drained conditions.

Bulbs are easy to plant. With a trowel or a bulb planter, dig a hole to the depth indicated on the plant label (use the label, which is 6in long, as a rough measuring stick). Set the bulb in the hole with the roots or the remnants of roots pointing down. Some bulbs—Spanish Bluebells, for example—don’t have visible roots but have a pointed or tapered top, which should be planted facing up. After you’ve placed the bulb in the hole, fill the hole with soil.

Bulbs grown in large, deep pots should be planted at the recommended depth. In small pots, plant bulbs at half the normal depth.

Watering Bulbs: Although there may be no sign of life above ground, bulbs begin sending out roots soon after planting—as long as the soil is sufficiently moist. Unless you expect a soaking rain within a day or two of planting, we recommend that you water thoroughly after you plant. Water newly planted bulbs again only if rainfall is scarce. Once established, most want ample moisture— 1/2 to 1in of rain per week—while in active growth (which begins in fall, slows or stops in winter, and resumes in late winter or early spring) and require soil that is on the dry side during summer dormancy. Do not plant bulbs near soaker hoses, sprinklers, or automatic watering systems.

Fertilizing Bulbs: The best time to fertilize bulbs is in fall, when they are sending out new roots. The next best time to fertilize is in early spring, just as the foliage begins to push through the soil. Heavy feeders such as Lilies and hybrid Tulips perform best if fertilized in both fall and spring. We recommend using a slow-release fertilizer formulated especially for bulbs, such as a granular Daffodil fertilizer. It’s an easy matter to apply the fertilizer to the surface of the soil (not in the planting hole) above the bulbs after planting and then every fall thereafter. We do not recommend using bone meal. It contains only one primary nutrient (phosphorus) and attracts dogs and rodents, which may dig up the bulbs.

Bloom Time: The bloom times printed on our labels are typical of bulbs grown in Litchfield, Connecticut. Where spring comes earlier, bloom will generally be earlier. Likewise, in colder climates, flowering will be delayed. Please note that the first spring after planting, most bulbs (particularly those imported from cool summer climates such as those of Holland and England) bloom later than established bulbs of the same variety. This is not unusual. In subsequent years, they will bloom at the appropriate time.

Aftercare of Bulbs: Most of the bulbs we offer go dormant within about 8–12 weeks after flowering. The period between the end of flowering and the withering of the foliage is crucial to the future vigor of the plant. If you cut, fold, or braid the leaves before they have yellowed and collapsed, you may prevent the bulb from storing the energy required to bloom the following year. You can hide curing foliage by interplanting bulbs with leafy perennials such as Hostas, Daylilies, and Ferns or with annuals or ground covers. If you plant bulbs in a lawn, do not mow the grass until the bulb foliage begins to yellow.

The best time to move or divide bulbs is when their foliage has all but withered, signaling the end of active growth. Lift them with a digging fork or a spade, taking care to avoid injuring the bulbs, and replant them immediately at the same depth and about three times their diameter apart.

Prechilling bulbs in mild-winter areas: In parts of the country where winters are mild, certain bulbs may not receive enough natural cold to stimulate proper growth and flowering. We recommend treating these as annuals and replacing them with new bulbs every year. Check with your local USDA Cooperative Extension Service to find out whether any bulbs require prechilling before planting in your area. Place the bulbs in a refrigerator, away from fruits and vegetables (these produce ethylene gas, which harms the embryonic flowers inside the bulbs). Make sure the bulbs remain dry. The usual prechilling time is 8–10 weeks at 40–45°F. Once the bulbs are removed from cold treatment, plant them right away. Bloom occurs about 6–8 weeks after planting. Discard the entire plant after bloom.