nyc compost project: mulching

Mulch is organic material such as wood chips, leaves, or partially composted material that is spread over the surface of the soil. Using mulch is a simple way to recycle yard trimmings and improve your garden.

Mulch reduces evaporation from the soil surface, keeps down weeds, and keeps soil temperatures from becoming too hot or too cold. Mulch also protects sloping ground from soil erosion, and it stops soil compaction caused by driving rain on any soil surface. In addition, mulch provides ideal conditions for earthworms and other soil organisms that are necessary for healthy soil. When mulches break down, they become a compost that feeds the soil.

A good mulch does all this—plus it's readily available, free, and easy to apply! Here's how:

general rules for mulching
mulch materials & their uses
applying mulch
where to find mulch materials
tools for making mulch

flowers SOME GENERAL RULES FOR MULCHING

Annuals and perennials (both flowers and vegetables) should be mulched with a material that breaks down in a relatively short time, such as grass clippings or shredded leaves. Tender plants must be able to break through the mulch surface. You can turn under the mulch on annual beds when the soil is dug up.

Woody plant materials should be mulched with a thick layer of shredded or chipped wood that will look good and require little maintenance. Paths can also be covered with shredded or chipped wood, in as thick a layer as is practical to wear longer and to keep weeds down. To keep paths weed-free even longer, put down layers of cardboard before spreading the mulch.

grass clippings MULCH MATERIALS & THEIR USES

Grass clippings can be spread regularly in thin layers over vegetable and flower beds, or mixed with leaves and spread in a thicker layer. Spread grass clippings no more than one inch thick so that they don't mat and stop water from penetrating into the soil. If you've used a herbicide, it is better to first compost the grass in a hot compost pile.

Whole or shredded leaves of deciduous trees can be spread as mulch in the fall. Evergreen leaves can also be used, but they take longer to turn a dark color and decay.

Chipped or shredded woody waste, if spread 3 inches deep, makes a good-looking, long-lasting mulch or path material. Pine needles make a good mulch for acid-loving plants such as rhododendrons, azaleas, and blueberries.

Local businesses may provide organic by-products such as sawdust free of charge. Sawdust and other finely-ground woody materials can be used on the surface, but don't mix them into the soil. These finely-ground materials that have not been composted may temporarily tie up nitrogen in your soil (see information on fertilizing), causing your plantings to become yellow and stunted.

APPLYING MULCH

Weed the area to be mulched before applying the mulch. Mulch can be spread around any plant as far as the distance of its outermost branching (this is called the drip line), or it can cover the entire garden bed. Mulch can be spread thickly if water is able to penetrate and if it does not smother the roots of the plant being mulched. For any woody plant 3 inches of mulch is safe; more may be placed on paths.

Thick mulches are harmful to shallow-rooted plants such as rhododendrons and azaleas. For any woody plant, don't allow mulch to touch the trunks; this helps prevent bark decay.

leaves WHERE TO FIND MULCH MATERIALS

The best place to look for mulching materials is right in your yard. Every yard has grass, leaves, other green materials, or woody materials that can be made into mulch. Put these materials to use in either compost or mulch.

If you need chipped or shredded woody wastes, try contacting a tree service listed in the Yellow Pages. If they are working in your area, they are often happy to deliver wood chips and avoid extra travel and dumping expense.

Some wood shops and food-related business make their organic by-products available to customers and the general public.

TOOLS FOR MAKING MULCH

A rotary mower run across dry leaves will make a fine-textured mulch for annuals and smaller plants. A small electric chipper will make a fine-textured mulch of semi-woody stalks and woody wastes up to 1-1/4 inch thick. Gas powered shredders of 5 to 8 horsepower that process up to 3 inches in thickness can be rented or purchased. Large gas-powered chippers to handle woody wastes up to 6 inches in diameter are available at rental shops. In general, the larger the machine, the faster the mulch-making..

For more information, see:
• soil health & compost
• seasonal guide to a healthy lawn (naturally)

nyc compost project | how to compost | compost science | nyc compost resources
sitemap