Physical Remedies
Mulch
Examples:
Compost, bark, composted steer manure, wood chips, leaves, dry grass clippings, sawdust.
Effective Against:
Annual weeds such as chickweed, annual bluegrass, bitter cress, etc.
Counteracts these pest(s):
When To Use:
Any time. Let vegetable beds warm up in spring before mulching so as not to slow plant growth.
How To Use:
Vegetable beds, perennial borders or beds, or around shrubs and trees. Follow these general guidelines for mulching.
- For annuals or herbaceous perennials, use a mulch of compost, dry grass clippings, leaves, or sawdust, 1-2 inches thick.
- For shrubs and trees, use coarse wood chips or bark, 2-4 inches thick.
For both methods, add new layers from time to time as mulch naturally decomposes. Keep mulch away from stems and crowns of plants. Don't incorporate bark or wood chips into the soil, spread them on top.
To kill a lawn in place in order to start or enlarge a garden: cover the entire area with sheets of cardboard or newspaper. Pile several inches of compost manure or other material on top.
Benefits:
Easy. Some mulch materials can be obtained free or at low cost. Provides some weed control. Weeds that grow in the mulch are easy to pull by hand because mulch material is loose.
Concerns:
Bark can be expensive. Leaves and wood chips tend to blow around. Wood chips and sawdust can deplete nitrogen if worked into soil; be sure to fertilize well. Add 3 pounds of nitrogen (in other words, 30 pounds of 10:0:0 fertilizer) per cubic yard of material.