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Using Mulch

 

Illustration of man collecting leaves and woman using mulch in a flower bed

 

WHAT IS MULCH?
Mulch is a protective covering of material that is spread over the soil surface to improve your garden. Organic mulches are made from recycled plant materials, such as compost, yard waste, or chipped woody materials like tree branches and Christmas trees. Organic mulches biodegrade and therefore must be replenished periodically. Inorganic mulches are inert materials such as plastic, fabric, or 
crushed stone.

WHAT DOES MULCH DO?
Mulch reduces evaporation from the soil surface, keeps down weeds, and stabilizes soil temperature. Mulch also protects sloping ground from soil erosion and stops soil compaction caused by driving rain on the soil surface. Organic mulches feed the soil and provide ideal conditions for earthworms and other soil organisms necessary for healthy soil–plus it’s readily available, free, and easy to apply!

WHICH MULCH?
Annuals (both flowers and vegetables): Mulch with finer materials that break down quickly, such as pesticide-free grass clippings or leaves. On annual beds, till the mulch into the soil at the end of the growing season.

Perennials & woody plants (shrubs, trees, etc.): Mulch with a thick layer (2-3 inches) of compost or chipped wood.

Paths: Mulch with a thick layer of shredded or chipped wood. To keep paths weed-free even longer, put down cardboard or several layers of newspaper before spreading the mulch.

HOW TO APPLY MULCH
Mulch can be spread around individual plants as far as the distance of the outermost branching (this is called the drip line); or mulch can cover an entire garden bed.

Weed the area to be mulched. Apply up to 3 inches of mulch, (see chart on back). Use less on shallow-rooted plants such as rhododendrons and azaleas. 

Be sure water is still able to penetrate the mulch; don’t smother the roots of the plants. Make sure the mulch doesn’t touch the stems of plants or the bark of trees as this could cause rot and invite pests and disease.

Winter mulches: Insulate the soil by applying compost, shredded leaves, wood chips, or evergreen boughs in late fall (after the first frost) to keep freeze and thaw cycles from damaging plants.

Summer or growing mulches: Apply lighter, organic mulches in spring (after the final frost) to improve the soil, reduce weed growth, and retain soil moisture.

Any time: Mulch can be applied any time in in perennial beds, around trees and shrubs, or on paths.

WHERE TO FIND MULCH

New York City residents can get free wood chips at at MulchFest in January, or through NYC Parks and Recreation borough offices. Another great place to look for mulch is right in your yard. Grass, leaves, or other green and woody materials can all be made into mulch. You can also use newspapers and cardboard. For chipped or shredded woody wastes, try contacting a tree service in the telephone directory. Some wood shops make their organic byproducts available. Don’t use sawdust or chips from pressure-treated or chemically-treated wood.

HOW TO USE COMMON MULCHES

Table with instructions on using various types of organic and inorganic mulch

HOW MUCH MULCH DO I NEED?

Most mulch is sold in cubic yards. Here’s a formula to figure out how much you need:
1. Multiply your garden’s length by the width (in feet) to find the area’s square footage.
2. Check the chart above to see how deep the mulch should be.
3. Multiply the area of your garden in square feet (from #1) by the depth of mulch in inches (from #2).
4. Divide the number you get (from #3) by 324. This is the number of cubic yards of mulch that you need.

Download a PDF of this Guide

Related Guides

About the NYC Compost Project funded by NYC Sanitation

The Department of Sanitation (DSNY) encourages residents to compost yard trimmings and food scraps in their own backyards and community gardens. This kind of composting is not only the least expensive way to manage organic waste, it also recycles nutrients close to where they can best be used to nourish our city’s soils.

The NYC Compost Project, created by DSNY in 1993, works to rebuild NYC’s soils by providing New Yorkers with the knowledge, skills, and opportunities they need to make and use compost locally. NYC Compost Project programs are implemented by DSNY-funded teams at seven host organizations, including Brooklyn Botanic Garden, Big Reuse, Earth Matter NY, Lower East Side Ecology Center, Queens Botanical Garden, Snug Harbor Cultural Center & Botanical Garden, and The New York Botanical Garden.

If you are interested in composting at home or in your community, the NYC Compost Project provides technical guidance on constructing composting systems and sells low-cost composting equipment. Each site also manages a compost help line to answer questions and to troubleshoot problems over the phone or by email.

NYC Compost Project -- Useful Links

compost project logo