How deep should I plant tulips?
Plant spring-flowering bulbs at a depth equal to 3 to 4 times their maximum bulb diameter. Accordingly, tulips and daffodils should be planted 6 to 8 inches deep, crocuses and grape hyacinths 3 to 4 inches deep. Large bulbs, such as tulips and daffodils, should be spaced 6 inches apart. A three-inch-spacing is adequate for crocuses, grape hyacinths, and other small bulbs.