An app that lets people mark the time and GPS location where they found wild berries or mushrooms. In the next season, they get a notification to revisit the location and collect the wild produce again.
Easy, free food every season.
An app that saves a specific location's GPS coordinates, time, a photo or video, and a description that you write about the location.
A few days before the peak of next season (same time next year) you get a notification to remind you that it's time to revisit the same area and pick what has grown.
Some mushrooms grow multiple times per year. If that's the case, you should figure out when the additional season(s) will be and set multiple notification alarms for each location.