Fall is the time to plant spring flowering bulbs outdoors. Whichever planting zone you live in, plant bulbs before the ground freezes in your area. Plant bulbs in the ground 3-4 weeks before a hard freeze so they can grow some roots, because even though they are dormant, bulbs do need to draw in moisture over the winter. New roots will also help bulbs in the spring, when they need plenty of moisture fast as their period of rapid growth begins.
Select firm, undamaged bulbs. Buy your bulbs as early as they are offered for sale in your area, and you will have the best selection. Gently squeeze packaged bulbs to make sure they are solid, and examine the root area: it should not be soft or moldy. Most bulbs are covered with papery, onion-like skin; don't worry if it is loose or even missing on small sections of the bulbs.
Prepare the planting site. Till or dig the soil to the proper depth for the bulbs you will plant. The general rule to determine the planting depth for bulbs is that a bulb should be covered with soil at least twice as deep as the bulb is tall. For example, if your tulip bulbs are 2 to 2 1/2 inches from top point to bottom root zone, you should cover them with at least 4-5 inches of soil. Add the height of the bulb, and the planting depth should be about 8 inches.
Use a bulb planting tool for naturalizing or for specimen plantings where you do not want to dig up a large bed. A bulb planting tool is a metal cylinder with a slightly conical shape, and a handle over the top (widest) part of the tool. The cylinder is marked with incremental depth measurements. To use this tool, push and twist it into the ground right where you want to plant the bulb. Pull out the plug of soil, place the bulb root-end down in the hole, and replace the soil. Firm the soil over the bulb.
Water the newly planted bulbs deeply. This provides moisture to get the roots started growing, and it helps the soil settle in contact with the bulb, eliminating undesirable air pockets.