                        MULCHES SERVE MANY PURPOSES

A mulch is a layer of peat moss, shredded bark or any similar material spread
on the surface of the soil under and around plants. The application of mulches
has many advantages such as improving plant growth, enhancing the appearance of
the landscape and reducing time spent in maintenance.

Value of Mulches

The most common reason for using a mulch is that it will eliminate or at least
retard weeds. Where the mulch layer is sufficiently deep, few weeds will grow.

By reducing the amount of soil water evaporation, mulches conserve moisture,
which is particularly important during droughty periods of the growing season.

Mulches aid in maintaining a uniform soil temperature. They act as insulation in
keeping the soil warmer during cool spells and cooler during the warm months of
the year. By maintaining uniform soil temperatures, freeze-thaw cycles during
winter are retarded, and heaving of perennial plants is reduced.

Mulching materials increase water-holding capacity of light, sandy soils and 
increase aeration of heavy clay soils as they gradually become mixed with the 
basic soil. 

Organic mulches serve as food for many micro-organisms found in the soil.  
During decomposition of the organic material, soil micro-organisms secrete a 
sticky material that promotes the granulation of the soil. The mulch also 
maintains more stable temperatures so the actively of the micro-organism can 
prevail at an even rate. 

Mulching aids in preventing surface soil erosion, particularly if mulch has been
established a few weeks.

In addition, mulches help keep leaves, flowers, and fruits free from soil, which
is important with strawberries, tomatoes, rock garden plants, etc.

Application of Mulches

The time to apply a mulch is in mid-spring when the soil has sufficiently warmed
up for active root growth. As applied before this, the mulch will keep the 
ground cool and root growth may be slow. If planting is done in autumn, apply 
the mulch immediately so that the soil temperature will be kept warmer longer. 

Most mulches should be applied at least 2 to 3 inches deep over the whole area.
Herbaceous plants that require winter protection may need an additional 1 to 2
inches in autumn around the crown or base of the plant.

Problem of Mulches

Weed seeds maybe introduced into the landscape with hay, straw and strawy 
manure and may serve as a source of weeds. Various kinds of hulls or corn cobs 
may have grain or seed mixed in. 

Molds often develop on cocoa bean and buckwheat hulls when they are kept too 
moist or in shady locations.  Stirring the surface of the mulch to aid in 
drying will eliminate molds. 

Several materials used for mulching require an addition of fertilizer to reduce
the chance of nitrogen deficiency of the growing plants. Wood chips, sawdust,
crushed corncobs, straw and shredded bark need additions of fertilizer. Apply
a complete lawn or garden fertilizer at the rate of 2 pounds per 100 square feet
before application of the mulch. If the foliage of the plants become yellow
during the growing season, additional fertilizer should be applied.

Types of mulches

Sphagnum peat moss is generally available and ideal for mulching evergreens and
other plants that grow best in acid soil. Its color is pleasing, it is free of
weed seeds, and it remains effective for one to two years,'depending on the
thickness applied.

Shredded bark makes an excellent mulch that lasts as long or longer than peat
moss. Bark chunks are available in various sizes and are valuable in 
beautification. 

Straw is used for winter protection and as a summer mulch in fruits and 
vegetable plantings. It may carry weed seeds and is flammable, so use it away 
from areas where cigarettes may be thrown. 

Crushed stone, gravel chip and pebbles are excellent in the landscape for 
effect in highlighting plants or garden features. They are available in 
various colors and can be selected to blend in with the features of the home, 
patio or landscape. 

Black polyethylene is used primarily in vegetable gardens, and both black and 
clear poly have been used in landscaping. Neither should be used in the 
landscape, however, as drying is reduced and wet soils and woody plants are 
not compatible. 

Crushed corncobs are used extremely extensively in some areas but do require 
supplemental fertilizer applications. Buckwheat hulls are fine textured and 
may blow in windy areas but have a good neutral color and are long lasting. 

Sawdust is commonly used where readily available. Nitrogen deficiency is 
almost certain if fertilizer is not applied regularly. Wood chips or shavings 
decompose slowly and may need additional fertilizer. 

Fiberglass mats, inorganic in nature, will not rot, corrode or burn and are 
long lasting but should be covered with bark or similar organic mulch. Salt 
hay, spent hops, lawn clippings, leaves, sugar cane, cocoa-bean hulls, leaf 
mold and paper pulp have all been satisfactorily used for mulching and, if 
available, should be considered. 

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Another text file from STONEHENGE BBS [415] 479-8328
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