Seasonality

You don't need to memorize a diversity chart. Just let the seasons rotate your ingredients for you. What grows in your region in spring is different from what grows in autumn — and that difference alone will widen your microbial ecosystem across the year.

Seasonal food is also usually cheaper, fresher, and richer in flavor. This is one of the few places where 'traditional wisdom' and 'modern nutrition science' point in exactly the same direction.