Forcing bulbs to grow is done indoors during the winter, when they would not ordinarily grow outdoors. Unfortunately, once you have used the flower bulbs in this manner, they will not always re-bloom, when you replant them outdoors. However, it is an easy process and worth the effort to see if they will come up next spring. Some common bulbs used for forcing are: paper whites, daffodils, amaryllis, hyacinths tulips, narcissus and iris.
Give your bulbs a period of chilling, generally, about 13 weeks (at 35 to 48 degrees). You can place them in the garage, garden shed or even the refrigerator. However, it's important not to let the flower bulbs freeze. This process simulates the bulbs wintering in the ground outdoors.
Decide on the container to be used for the forced bulbs. The most common way of planting indoor bulbs is with a shallow container with holes at the bottom. Throw some gravel or stones on the bottom of the container to help with water drainage.
Add enough commercial potting soil, to the bottom of the container, so that the bulb points will be even or above the top of the pot. Place the flower bulbs close together. In fact, they can be shoulder to shoulder, unlike outdoor planting, where there should be space between them. Loosely cover the bottom part of the bulbs with soil, leaving the points exposed. Do not pack the soil.
Water the container, thoroughly. There is no need for the use of any fertilizer or other feeding as the bulb contains all the nutrients it needs to grow and bloom for one time.
Water the plant on a regular basis, when the soil starts to dry.
Place the planted bulbs in a location that receives direct sunlight.