Characteristics of some weed-free mulches:
Bark chips
•Long-lasting
•Moderately good at smothering small weeds
•Not as good at conserving moisture as most other mulches
•Looks attractive
Compost
•Weed-free if properly made
•Contains a smorgasbord of plant foods
•Helps prevent diseases
•You can plant seeds right into it
Grass clippings
•High in nitrogen
•Thick layers will heat up, so apply only 1 to 2 inches (not near stems of young plants)
•Very good at smothering weed seedlings
Hay
•Meadow hay, if clean of weed seeds, adds nutrients as it decomposes
•Salt hay, gathered from marshes, is clean of weed seeds that will grow in your garden
Hulls and shells
•Includes hulls and shells of peanuts, buckwheat, cocoa beans, and rice
•Fairly rich in nutrients
•Best for smothering weed seedlings or keeping weeds out of weed-free area
•Attractive in formal or informal gardens
•Longevity varies
Leaves
•Weed-free except for occasional tree seeds
•Good at smothering weeds
•Holds soil moisture very well
•Tends to blow away when dry or exposed
Peat moss
•Poor in nutrients
•Attractive
•Tends to blow away when dry
•Repels water when dry, and is hard to re-wet
Pine needles
•Long-lasting
•Moderately good at smothering weeds
•Attractive
•Effect on soil pH is minimal
Seaweed
•Nutrient rich
•Not long lasting
•Excellent at smothering weeds when fresh
Straw
•Weed-free because it includes only the stem and leaves of grain plants, not the seeds
•Must be reapplied annually
•Very good at smothering weeds and holding soil moisture