Many hunter-gatherer societies know all they need to know about growing plants, but don't. Some gatherers do plant seeds. Some gatherers replant parts of root crops. Most cultures based on seeds, not root crops. Many root crops important in the lowland tropics.
Some gatherers also irrigate.
Gatherers learned how to cook and to detoxify foods in many cases. This might have been especially true around houses or cattle pens. Both are also disturbed areas. Parts of the plants that were utilized were often discarded. Carl O. Sauer felt man had to be sedentary first.