Compost and mulch. Both are great soil conditioners, but how do they differ?

Each serves as a time-release fertilizer and insulator.

When augmented with livestock and poultry manure, nutrient-rich compost leaches into the earth and feeds countless microorganisms, earthworms and fungi.

With time, watering and mixing, discarded green kitchen scraps, yard litter and garden wastes decay into crumb-textured "brown gold" -- a greatly enhanced growing medium.

Mulch, meanwhile, is a protective cover that also works its way into the topsoil. It's made up of natural or synthetic substances -- everything from crushed rock and plastic sheeting to wood chips, discarded newspapers and straw.

Mulch minimizes gardening chores by smothering weeds, conserving moisture, eliminating erosion and aerating packed soils. It also protects tender plants from frost and cold in winter and from evaporation and heat stress in summer.

Compost generally is applied as a soil amendment in late fall or early spring in layers 2.5 to five centimetres deep. Coarse mulch then can be layered over the enriching compost to protect young plants from the elements. Both are available for little or no cost.