Ferretti also points out that vegetables are highest in vitamins and minerals such as potassium, magnesium and iron when they are fully ripe. They will be cool and firm and will not have absorbed any natural field heat. Ferretti says home growers can become savvy harvesters by remembering just a few tips about each crop. The ripening tomatoes will have slightly lower amounts of vitamins and minerals than the fully ripe fruits. Green peppers are picked and used before full ripeness, so Ferretti recommends that gardeners gauge ripeness by the size estimate on a seed packet or in a seed catalog.
Firmness also is a ripeness indicator.
If the pepper feels as though it has thin walls, it is not ripe. If peppers have ripened to full color, use them quickly because they have only a few days of shelf life at that stage. Ferretti says zucchini tastes best when harvested at lengths from 6 to 10 inches. After 8 to 10 inches, zucchini gets tough and develops more seeds. Longer zucchini that escaped your attention during picking can be grated, or breaded and fried.