List of Northern American nectar sources for honey bees

The nectar resource in a given area depends on the kinds of flowering plants present and their blooming periods.

A good predictor for when a plant will bloom and produce nectar is a calculation of the growing degree days.

Hopkins' bioclimatic law states that in North America east of the Rockies, a 130-m (400-foot) increase in elevation, a 4° change in latitude North (444.48 km), or a 10° change in longitude East (two-thirds of a time zone) will cause a biological event to occur four days later in the spring or four days earlier in the fall.

[1] In botany, the term phenology refers to the timing of flower emergence, sequence of bloom, fruiting, and leaf drop in autumn.

The nectar sources from large cultivated fields of blooming apples, cherries, canola, melons, sunflowers, clover, etc.