You can learn now when farmers are spraying pesticides near your home. Here’s how.

After years of health concerns and advocacy from residents who live near farms, California has launched a first-in-the-nation program to let the public know beforehand when pesticides are going to be applied on agricultural fields.

The program, called “Spray Days,” was started last month by the state Department of Pesticide Regulation.

It allows people to enter their address and sign up to receive an email or text message alert at least 24 hours before farmers apply “restricted material...