That's starting your own flowers and vegetables, inside and out. It's raising shrubs and trees for your property, creating your own orchard - even growing many houseplants from one. You don't need a greenhouse or costly equipment. You can do a lot with a couple of fluorescent bulbs.
Seeds are cheap, some are free.
As for shrubs, trees and houseplants, Lewis Hill explains how to collect, rather than buy, the materials you'll need. It's fun, can be profitable, and, with the help of Lewis Hill plus the many illustrations in this book, is easy. Try plant propagation. You'll be amazed at the results. 168 pages, softcover.