Check the color, and look for a light brownish-white color from top to bottom. If you see dark brown spreading from the base, it could be a fungal disease called basal rot.
You should adjust this based on your soil type — for sandy soil, you'll want to dig deeper than 2 inches. For heavier soil, make the hole more shallow.
Daffodils need 12-16 weeks of dormancy in temperatures ranging from 35-45 degrees. Depending on your growing zone, this time may vary by a week or two.
If small green shoots don't emerge, transfer the bulbs to pots and put them in a dark, cool place. Once shoots appear, move them outside or keep them in a sunny spot indoors.
Choose a sunny spot so the bulbs receive at least six to eight hours of sun daily. Daffodils can tolerate some shade, but they'll perform best if it's afternoon shade.
To avoid this, space your bulbs 4 to 6 inches apart when planting. Vary the types of daffodils and their positioning to create a full look without overcrowding.