The following is an excerpt from Window Boxes Indoors and Out by James Cramer and Dean Johnson.
The paperwhite narcissus, with its marvelous heady scent, is easy to force into bloom between October and March. It takes about 5 weeks for the blossoms to appear; once they do, they’ll thrive in a cool room. Plant in early October for Thanksgiving bloom and in November for Christmas. Plant every 2 weeks for a continuous supply of blossoms; the bulbs will bloom faster as spring approaches. This whitewashed wooden window box has a primitive picket fence made of lathe. Because the paperwhites’ bending stems tend to get heavy and flop over as they grow, we made V-shaped cuts in the corner pickets and laid twigs across as supports.
Plastic window box liner
Paperwhite narcissus bulbs
Fit a pretty wooden window box with a plastic liner. Fill half the container with packing peanuts, then top with river gravel. Set upright bulbs on top of the gravel about an inch apart, anchoring them with a few more pebbles. Roots will grow down to hold the paperwhites upright. Add enough water to just reach the base of the bulbs. Top with sheet moss.
Place the window box in a cool dark place for 2 to 3 weeks to encourage root growth and subsequent sprouting. When pale green shoots are 3 to 4 inches tall, bring the container to bright indirect light for a day or two, then move it to a sunny window where the temperature is cooler than 70°F. The paperwhites will bloom in 2 to 3 weeks.
Stems will bend toward the light; rotate the container each day to keep them straight. Monitor the water level so the roots are not exposed.
Photography by Gridley & Graves from Window Boxes Indoors and Out