Known for the ease with which they can be forced indoors, paperwhites (Narcissus spp.), a type of daffodil, produce delicate flowers that add beauty inside the house during an otherwise drab time of year. Because the forcing process depletes most of the energy from the bulbs, paperwhites are usually thrown away after blooming. If you live in U.S. Department of Agriculture plant hardiness zones 8 through 11, though, you can plant them outdoors in the spring. They are unlikely to bloom the first year after planting, but the bulbs should build up enough energy in two or three years to become reliable bloomers in your garden.
Place paperwhites growing in soil in a sunny location indoors. If the bulbs were forced on rocks rather than in soil, plant the bulbs in potting soil so the tips of the bulbs are just under the soil. Then place them in a sunny location.
Fertilize once using a houseplant fertilizer at half strength. If for example, you use a fertilizer with the nutrient analysis 24-8-16, 1/8 teaspoon mixed with 1/2 gallon of water should suffice at watering time.
Maintain moist soil conditions until it’s time to plant the paperwhites outdoors. Cut the foliage to the soil if it dies back. Do not remove paperwhite foliage while it’s still green, because this is when the plant is making and storing energy in its bulbs for future flowers.
Work the soil outdoors in a sunny location 8 to 12 inches deep; work 3 or 4 inches of organic matter into the soil. Paperwhites prefer morning sun and afternoon shade. Also work in a balanced or bulb fertilizer using the rate recommended on the label. For example, apply 1 pound of 5-10-5 fertilizer per 25 square feet of garden area.
Plant the bulbs outdoors after the last spring frost so the bottoms of the bulbs are 5 to 6 inches below ground. If the foliage is still intact, bury it to reach the desired depth. Space bulbs 1 to 3 inches apart, or cluster about 10 to 15 bulbs per square foot, recommends North Carolina State University. Water the bulbs with 1 inch of water after planting.