Mulching: a simple practice for healthy vegetables, flowers, trees, and shrub

Mulching is one of the simplest and most beneficial practices you can use to promote healthy vegetables, flowers, trees, and shrubs. Mulches can be either organic--such as grass clippings, straw, bark chips, leaves, compost, and similar materials--or inorganic--such as stones, brick chips, landscape fabric, and plastic. Before you decide which mulch is best for you, consider what you hope to achieve by mulching. Do you want to mulch for weed control, moisture retention, soil improvement, or beautification?

Mulch materials

Bark mulches resist compaction, will not blow away, and are readily available

Mulch materials are readily available in your own yard and house! Lawn clippings make excellent mulch in vegetable gardens. The fine texture allows clippings to be spread easily, even around small plants. Three layers of newspaper weighted down with another mulch or other means can effectively keep down weeds, especially in vegetable gardens. Shredded newspaper also works well. Leaves chopped with a lawnmower or shredder and composted over the winter can be used as summer mulch.

Compost, a mixture of decomposing vegetable refuse, manure, etc., makes wonderful mulch, if you have a large supply. Compost not only improves the soil structure, but provides an excellent source of plant nutrients. You can use the following items for compost: grass clippings, leaves, plant stalks, hedge trimmings, old potting soil, twigs, annual weeds without seed heads, vegetable scraps, coffee filters, and tea bags. Do NOT compost these items: diseased plants, weeds with seed heads, invasive weeds such as quack grass and morning glory, pet feces, dead animals, bread and grains, meat or fish.

Bark chips and composted bark make an attractive finish for a garden bed and will eventually improve the condition of the soil. Bark chips and composted bark are excellent for use around trees, shrubs, and perennial gardens. Smaller chips tend to be easier to spread, especially around smaller plants. Bark mulches resist compaction, will not blow away, and are readily available. Some shredded barks, such as cypress, decompose slowly. Bark chunks decompose most slowly, but have a tendency to wash away.

Depending on where you live, numerous other materials make excellent mulches. Hay and straw work well in vegetable gardens, although they may harbor weed seeds. Seaweed mulch, ground corn cobs, and pine needles can also be used. Pine needles increase the acidity of the soil, so they work best around acid-loving plants such as rhododendrons and blueberries.

How to mulch

Summer mulches for annual flowers and vegetable gardens are normally applied in mid-spring, once the soil has warmed enough for active root growth. For best weed suppression in a perennial border, apply mulch in early spring, before the forsythia blooms. For best results, remove any existing weeds before applying mulch. Mulches applied for winter protection should be applied in early winter, once the soil has cooled but before it has frozen.

For trees and shrubs, spread mulch evenly to a depth of two to three inches. For trees and shrubs in beds, mulch the entire bed. For those in a lawn, mulch a wide ring (extending from three to six feet out from the trunk) around each plant. Never pile mulch against tree trunks. Pull mulch back from the trunk about an inch or so. As organic mulches decompose, they may need to be replenished every year, but do not let mulch build up to depths greater than four inches.

For flower beds, mulch can be applied up to three inches deep (after settling), but should be kept back slightly from plant stems. Mulches should thoroughly cover an area to a uniform depth to be most effective. Low or bare spots are prone to weed problems. Grass clippings make good mulch for flower beds. Grass clippings should be spread immediately after cutting to avoid heating and rotting.

Sources of mulch

Check in the Yellow Pages under mulches, nurseries, or garden centers. Your community may also have wood chips from the removal of street trees that are available free to residents. Mulch can often be purchased bagged or in bulk from garden centers. Bulk purchases may be cheaper, if you need a large volume, and have a way to haul it. Bagged mulch is often easier to handle, especially for smaller projects. Most bagged mulch comes in 3-cubic-feet bags.

Note: Mulch is measured in cubic feet. For example, if you have an area ten feet by ten feet and you wish to apply three inches of mulch, you would need 25 cubic feet.