Spring or summer plantings of daffodils run the risk of rot, rodents and other ills, but with good drainage and careful attention, it can be done. Planting spring bulbs, such as daffodils, is best done in the fall, before the first frosts hit and while the ground is still easy to till. If you plant in the spring, fertilize well--and expect to wait a year or more, before they will next flower for you.
Choose a sunny location and, ideally, one where you will enjoy these harbingers of spring from your kitchen window. Daffodils, jonquils and paperwhites are early-spring bloomers, known by the botanical name "Narcissus." These bulbs require good drainage and periodic feedings of a general fertilizer. Some gardeners add bone meal, as well. It is best to plant bulbs that are not already in bloom.
Plant the bulbs with the dried roots at the bottom (flatter side down) and the more pointed side up. Consider the landscaper's trick of planting in groupings of threes and fives, for a more professional appearance. Daffodils look great in clumps, and they will increase and divide, over the years.
Use a bulb planting tool (like a wide cylinder or tube of metal, with a handle) or use your hand-held garden spade to make holes of about four inches to six inches in depth. The bulb should be planted at least as deep as the bulb is high--so if you have a two-inch bulb, plant it at least four inches deep. Shallower plantings will increase (and need to be divided) sooner.
Protect the bulbs before winter hits, by mulching well with dried leaves, a commercial mulch or pine needles. In the spring, after danger of frost is past, gently remove the mulch around the emerging plants.
Check the plants periodically, especially if you have planted in the springtime. Continue to fertilize and water, over the summer months.
Mulch well, before winter, and cross your fingers for next year. You may skip a summer, before the next blooms appear, but continue to water and fertilize, to help the bulbs store food for the next blooms.