The chapter mentions interplanting with things that don't compete for space, and then compares that to companion planting, which capitalizes on how plants can benefit each other. This is a step in the right direction, but is still a little too close to monoculture. Jocelyn brings up that plant communities are dynamic, and not static, so it is important to create a real plant community. Polycultures are self-organizing, and multi-organism plant communities. Paul and Jocelyn talk about Ianto Evans' gardens. Ianto invented the rocket mass stove. Yield is greater in a polyculture than in the same sized monocrop.
Toby's advice is: to seed several varieties of each species; don't sow seeds too thickly; begin harvest early; mix plant families, (not just species); include many seeds of fast growing, shallow rooted species; overlap the harvest; avoid root-light competition; harvest whole plants; save a few plants for seed; and examine it every day. Paul talks about Sepp Holzer's approach. Paul describes what a guild is. Toby talks about the 3 sisters. Guilded corn yield can be 3 times larger than monocropped corn. Paul brings up his debate with Helen Atthowe. And lastly, Paul and Jocelyn talk about the "4th sister," in the southwest, the rocky montain bee plant. With diversity comes greater (and more quality) yield.