The best time to plant daffodil bulbs is when the ground has cooled off. September through November is the usual time for planting daffodils, depending on your location. The American Daffodil Society (ADS) recommends visiting display gardens in the spring to see what colors and forms appeal to you, and then ordering them from bulb companies and catalogs. The companies will ship the bulbs when it is time to plant them in your particular USDA plant hardiness zone. The ADS has other tips for successful daffodil growing.
Daffodils need well-drained soils to thrive. Planting them in raised beds or on hillsides generally works well. Dig 12 inches deep, and amend clay types of soil with compost, soil amendment or planting mix. Daffodils prefer soil that is slightly acidic. You can ask the local cooperative extension to test a sample of soil to find out what the pH level is. Soils that are too alkaline can be amended with soil sulfur.
Plant the daffodil bulbs twice as deep as their height. If the bulbs are 2 inches, plant them 4 inches deep. Keep the pointed ends up. If the soil is sandy, they can be placed a little deeper. After the leaf tips emerge, top dress the plants with a low-nitrogen fertilizer. Fertilizer that is 5-10-10, 0-10-10 or 0-0-50 is appropriate for use on daffodils.
Daffodils require a lot of water. Water them after planting, and keep them moist until rainy weather begins. Daffodils need adequate watering until 3 weeks after bloom time. It is during this time period that the bulb is preparing a bloom for the following season. Never cut the foliage until it begins to yellow. The daffodils will continue to bloom each spring for 3 to 5 years. If they skip a year, dig them up and move them to a new spot.