Chiggers go through a complete metamorphosis life cycle and contain four separate and distinct stages: egg, larva, nymph, and adult.
In the spring, Adult female mites lay from one to five eggs per day in leaf litter, vegetation and lawns. After five to seven days, the eggs hatch into 6-legged chigger larvae.
Chigger larvae will feed on the skin tissue of a warm-blooded host for 3-4 days and then drop off the host to molt.
After a week or ten days in the ground, the larvae molt into a nymph with eight legs.
After two weeks to one month, nymphs molt into adults. An adult chigger mite resembles the nymph, but is larger.
Chigger mites are active when the ground temperature is between 77°F and 86°F.
Adult chiggers overwinter in protected places. They will die if exposed to temperatures colder than 42°F.
In total, the life cycle of the North American chiggers require 50 to 70 days to develop from egg to adult.
In Minnesota there is only one generation per year.