a covering, as of straw, compost, or plastic sheeting, spread on the ground around plants to prevent excessive evaporation or erosion, enrich the soil, inhibit weed growth, etc.
Origin: 1650–60; noun use of obsolete mulch (adj.), Middle English molsh soft, Old English myl(i)sc mellow; cognate with dialectal German molsch soft, overripe
1650s, from M.E. molsh (adj.) "soft, moist" (early 15c.), from O.E. melsc, milisc "mellow, sweet" (cf. Du. mals "soft, ripe," O.H.G. molawen "to become soft," Ger. mollig "soft"), from PIE base *mel- "to rub, grind." As a verb, attested from 1802. Related: Mulching.