A layer of organic or inorganic material spread on soil surface to suppress weeds, conserve moisture, regulate soil temperature, and improve soil structure as it decomposes.
In plain terms
Spread 2-3 inches of mulch around plants and beds. Organic mulch (wood chips, leaves, compost) suppresses weeds, retains moisture, keeps soil cooler in summer, moderates temperature swings, and feeds soil biology as it decomposes. Inorganic mulch (gravel, landscape fabric) doesn't break down but requires no replacement. Organic mulch is superior for garden health; replace annually as it decomposes.
Why this matters
Mulch is one of the highest-return garden investments. It saves watering, reduces weeding, moderates temperature, and improves soil over time.
In practice
Examples
3 inches of wood chip mulch around shrubs; weeds suppressed, water conserved, soil improves yearly.