What is seed saving, and why is it important?
Seed saving involves letting a plant go through its entire life cycle in order for it to produce seed, at which point that seed is harvested for use in later plantings. The specifics of how this is done vary from plant to plant. Yes, the steps involved in saving seed from a tomato variety, a lettuce plant, or a chayote are completely different, but the objective is the same: to enable the plant (and, by extension, what the plant produces in terms of edible product) to propagate across space and/or time.
Some of our favorite seed saving resources are provided below.
Seed Saver Reference Chart
A bunch of Seed Freaks from downunder have compiled this very useful snapshot indicating the factors involved in saving seed from the most commonly grown plant types.