Tulip bulbs can be forced to bloom indoors during winter months if you plant them in a pot in the fall and give them a good chill for a few months. The process takes three to four months from planting until the flowers bloom. If you plant a few pots of tulip bulbs every week during October and November and bring the chilled pots into warmth a few at a time, you’ll have a continuous supply of blooming tulips for six to eight weeks beginning in January.
Choose shallow pots or use “bulb pans” or “bulb pots,” which are terra cotta or plastic pots specifically made for forcing bulbs indoors. They are similar to regular indoor plant pots, except they are a little shorter. Depending on their size, plant seven to nine tulip bulbs in a 6- to 8-inch pot.
Put a rock or broken pot shard over the drainage hole in the bottom of the pot. Fill pots to within three inches of the top with regular indoor potting soil. Rap the bottom of the filled pot on a hard surface to settle the soil. Gently firm and level the surface of the soil.
Set the tulip bulbs on the surface of the soil, with pointed ends up. Place the bulbs close together but not touching. The tops of the bulbs should be slightly below the rim of the pot.
Add more soil to fill in around the bulbs and bring the level of the soil up to within about a half-inch of the top of the pot. Rap the bottom of the pot on a hard surface to settle the soil. The tips of the bulbs should be just poking out of the surface of the soil.
Water thoroughly, until the water runs out of the bottom of the pot.
Chill bulbs for 10 to 12 weeks. During this time the tulip bulbs will grow roots and begin to grow leaves and a stem. Store the pots where the temperature is between 32 to 45 degrees Fahrenheit. An unheated garage is ideal if you live in an area with mild winters. In more severe climates, an unheated closet or basement works well. You can also put the pots in a cold frame and surround them with 12 to 24 inches of dried leaves.
Bring the pots of tulip bulbs into bright, indirect light at a temperature of 50 to 55 degrees Fahrenheit after 10 to 12 weeks of the cold treatment. Water the pots well when bringing into warmer temperatures. Water again only when the surface of the soil is dry to the touch.
Move the pots of tulips into bright sunlight and regular room temperatures in the upper 60s after seven to 10 days at temperatures in the 50s. During this phase, move the pots to a cooler area with temperatures in the low 60s during the night until flower buds form. Once the buds are set, leave the pots at room temperature all the time. The tulips will bloom approximately two weeks after first moving the pots to warmer daytime temperatures.