MULCHING AROUND - The New News
- Mulch is as much a part of gardening as soil, fertilizer,
watering, planting and pruning. It is often even more important
- Mulch is applied to the surface of the soil, it conserves
moisture, moderates soil temperature, controls weeds, maintains
physical structure of the soil, and prevents soil erosion,
...just like leaf litter in a forest.
- Mulch can be organic (leaves, shredded bark, pine needles,
straw, recycled ground wood waste or tree trimmings) or inorganic
(stones, plastic film, aluminum foil). Organic mulches improve
the soil while inorganic mulches do not.
- Mulch conserves moisture by blocking the sunlight and insulating
the soil. When sunlight hits unmulched soil the soil heats
up and speeds evaporation. Mulch shields the soil surface
from wind slowing evaporation
- Studies have shown that a thick layer of mulch prevents
rapid swings in soil temperature. The mulch buffers the temperature.
Plants grow better when temperature is relatively constant,
extremes or rapid changes in soil temperature halt root growth.
Also prevents soil heaving in freezing temperatures.
- Saves a lot of work and time spent weeding. Many types of
weed seeds need light to germinate. Mulch does not allow light
to reach the soil surface hence the weed seeds do not germinate.
Weeds that do germinate are easy to pull out.
- Over time organic mulches improve the fertility and physical
structure of the soils they cover. As they decay they release
the nutrients they hold (the original slow release fertilizer).
- Mulch helps prevents soil erosion. Rain (or sprinkler) droplets
hit unprotected soil forcefully enough to shatter soil aggregates
allowing the soil to wash away. A mulch layer breaks the fall
of water droplets and keeps the soil intact. It also prevents
mud from splattering onto plant leaves (looks bad and might
spread disease organisms), foundations and walks. Mulch slows
the flow of water allowing it to soak into the soil and not
runoff as waste. Mulch provides food and shelter for earthworms
whose tunnels greatly increase absorption of rain by the soil
preventing runoff and reducing erosion.
- Many insects such as cutworms must lay their eggs directly
on the soil, having a thick mulch stops the reproductive cycle
and reduces or prevents the pest.
- Mulches help prevents soil crusting thus increases in-soak
and aeration. This is done by preventing moisture from moving
up in the soil and evaporating in the air leaving behind the
dissolved minerals as a crust.
- Organic mulches provide shelter for frogs, toads, lizards
and other beneficial animals and insects. These animals and
insects help control the bad insects.
- Organic mulches attract and provide food for earthworms.
Earthworms are a valuable resource in the garden. Earthworms
tunnel deep into the soil allowing air and water to easily
reach plant roots. As mulch and soil pass through the earthworm
they are transformed into castings that are rich in minerals
that plants need. Many species of earthworms actually eat
the bad microbes (fungi, bacteria, etc.) that are plant pathogens
and in the process they also increase the good beneficial
microbes. Chemicals in the earthworm cause the castings to
form aggregates in the soil that are resistant to erosion.
Some species of earthworms even eat many types of weed seeds.
- Compost is excellent mulch and contains microorganisms that
help prevent damping off disease. The microorganisms in the
compost are competitors of the pathogens such as Pythium and
- Mulches increase the size and depth of the root zone of
- Provides walkways to keep feet from getting muddy.
- Decomposes slowly and helps to improve the condition of
soil. A good mulch will loose 2/3 of it volume be decomposition
in one years time along the Gulf coast improving the soil
in the process.
- Organic mulches increase the organic acids (i.e. humic,
fulmic, etc.) in the soil that help to release the nutrients
contained in the soil.
- Organic mulches improve the appearance of any flowerbed
- Bare ground, without mulch or plants is an invitation to
weeds...natures abhors bare ground.
- Scientists from the Agricultural Research Service found
that grass and leave mulched plots had twice as many earthworms
as those mulched with cornstalks. Water penetrated the earth-worm
filled soil up to 4 times faster.
- Mulch helps trees withstand stress better. After the 1993
flood in the Midwest it was found that trees that were mulched
and well established had the highest survival rate. Michael
Hopps, Urban Forests, 1994
- If compost is applied as a mulch in winter, the dark color
helps warm the soil by absorbing heat from the sun stimulating
plant growth and the release of nutrients in the soil by microorganisms.
EXTRA BENEFITS OF NATIVE MULCHES
- Native Mulch is the highest quality mulch available. It
protects and improves soil better than other types. It also
resists erosion better and protects the soil better than most
mulch. Since it is made from recycled tree limbs it is also
good for the environment.
- Scientists have found that mulch from shredded tree limbs
does a better job of resisting soil compaction than plywood
or any other traditional approaches. Course ground trimmings
6" or deeper to 18" can be used without hurting
deciduous trees provided that the soil has good drainage.
Morton Arboretum, Lisle, Illinois
- Mixed hardwood mulches or native mulches (not bark) encourage
the growth of fungus fibers that glue mulch fragments together
and to the soil thus preventing erosion.
- Mulches as they rot provide the preferred food of many insects
and organisms whom eat plants if mulch is not available (i.e.
they attack plants only if they cannot find enough natural
food). Mulches made from natural wood materials are the best
- Homeowners are advised that natural wood chip mulches attract
other ant species that prey on the queens of imported Fire
Ants. Avant Gardener, April 1994
- Thick mulch made from ground plant material is home to billions
of beneficial microbes. These microbes help digest the organic
material releasing the nutrients and creating valuable humus
in the process. Mulch also stimulates the growth of other
microorganisms that release minerals stored in rock particles
in the soil increasing soil fertility.
- Mulches made from ground up tree and vegetative material
is many times higher in nutrients than barks (i.e. pine bark).
Native or natural mulches from recycled materials have a high
percentage of buds, shoots, leaves, and cambium bark layers
in them. These materials are rich in protein and other nutrients
which is the reason deer and other animals eat them as a food
- Mulches made from ground up tree and vegetative material
tends to lock together (both physically and by fungus fibers)
and not float off in a hard rain as most barks do.
- Thick mulches made from ground up tree and vegetative material
has many uses
- they can be used to prevent injuries on playgrounds
- they are used for jogging/hiking trails
- powerful erosion control material
- used as silt screens to filter runoff
- Mulches in the shape of flakes or nuggets tend to wash away
easily in heavy rains (i.e. pine bark). While fibrous native
mulches tend to lock together and stay in place better.
that copy nature work best. Biodegraded mulch (i.e. composted)
next to the soil surface with newer and less degraded material
(fresh) on the surface. A variety of mulch particle sizes
also works best (just like what occurs on a forest floor:
leaves, twigs, limbs, and logs).
- Use of native mulches helps save valuable landfill space
by recycling grass, leaves, trees limbs and other woody material
that would otherwise be buried and wasted.
- University of Tennessee research has shown that the use
of loose or coarse mulches provides an environment attractive
for beneficial spiders. These resident spiders were found
to reduce insect damage 60-80%. None of the spiders attracted
to test plots were poisonous, half were not web builders,
and many were small and stayed out of sight. Texas Organic
News, Vol II No. 2
- Researchers have found that mulches made from yard waste
(wood chips, grass and leaves) were the best type of mulch
for Avocado and Citrus trees. The mulch increased the growth
and health of the trees and encouraged the growth of beneficial
microorganisms (biocontrol agents) that prevent soil borne
diseases of these trees. Journal of Horticultural Science
(1995) 70 (2) 315-332
- Mulches made from recycled partially composted wood wastes
that have lots of "fines" or small particles sizes
are easier for worms to use (swallow and eat) increasing earthworm
populations. The increased particle surface area of the small
sizes also allows for greater microbial activity that is preferred
- Research at the U.S. National Arboretum has found that large
pile composting of wood waste eliminates (kills) the pathogenic
fungus Botryosphaeria dothidea, a canker causing fungus known
to infest Cercis (Redbuds), Rhododendrons (Azaleas), Syringa
(Lilacs) and Prunus (Peaches, Plums, Cherries, etc.) species.
It also found that similar pathogenic fungus is also killed
by composting at temperatures over 122EF. This method is also
used for wood chips that line paths, in mulches and in soil
amendments. Nursery Management and Production, September,
- According to California Agriculture, published by University
of California, composted yard trimmings (lawn clippings and
tree trimmings) applied as a mulch deserve credit for reducing
brown rot disease in a San Joaquin Valley research plot. Adjacent
plots treated with traditional composts and fertilizers. Compost
amended trees had 0% brown rot and unamended control had 2.5%
while the trees in the conventional grown plot had 24%. Fruit
grown with compost had millions of yeast spores on the fruit
surface which is believed to block or prevent brown spot.
BioCycle, December 1995.
- Researchers at Auburn University have found that the type
of mulch applied significantly affected yields of collards.
The highest yields were obtained with a native wood chip mulch.
HortScience, Vol. 31(5), September 1996
- Experiments with Gleditsia tricanthos inermis ("Honey
Locust") have found that destructive necteria cankers
are greatly reduced when grown with a native mulch. Avant
- Trees worldwide are having a decline problem that results
in increased disease and pest problems and in eventual tree
death. This problem has been linked to unhealthy soil caused
by over use of synthetic chemicals and improper soil management.
The recommended treatment is composted wood and/or leaves
applied around the base of the tree. Dr. Alex Shigo, Tree
Care Industry, October 1996.
- Using mulch saves money ($$$) both directly and indirectly.
The US EPA says eroded sediments account for 80% of the pollution
of the nation's streams. This cost billions of dollars in
extra treatment of drinking water, infilling of water supplies,
hydropower and flood control reservoirs, increased dredging
of shipping channels, and other impacts too numerous to mention.
This does not include destruction of wildlife habitat, lagoon,
marsh and wetland destruction, or human health risks/costs.
Erosion Control, Nov./Dec. 1995.
- In Texas, it is estimated that we loose 4,000 pounds of
humus per acre every year do to breakdown in the soil as a
result of our high temperatures (Neil Sperry's Gardens, Nov.-Dec.
1996). Hence it is critical for soil health to keep it covered
with a thick layer of mulch. Native mulches rapidly increase
the humus content of soils.
- Plants grown in substrates rich in biodegradable organic
matter support microorganisms that induce systemic resistance
to disease. American Nurseryman, October 1, 1997. Note: Composted
Native Mulches have extremely high levels of beneficial microorganisms
while bark mulches like Pine and Hardwood have chemicals that
prevent/reduce biodegradability and even suppress beneficial
- A 20 year study by the University of Quebec has found that
native mulches improve soil quality better and faster than
any other material.
- Mulches are extremely cheap for the benefits they provide.
Studies have shown that if people whom use or specify synthetic,
cancer causing, agricultural chemicals, who are destroying
the soils, polluting the air and water, destroying our health,
increasing erosion of our soils, etc. would take full responsibility
for their actions, then the cost of using synthetic chemicals
would cost hundreds to thousands of times more than natural
techniques. The benefits, both cost and function, of mulches is so overwhelming
that several states have now passed legislation requiring
the use of mulches.
The Mulch Book - A Complete Guide For Gardeners, Stu Campbell,
Revised and updated by Donna Moore, Storey Publishing, Copyright
1991, ISBN 0-88266-659-2
The Rodale Book Of COMPOSTING, Deborah L. Martin and Grace
Gershuny, Editors Rodale Press, Emmaus, Pennsylvania, Copyright
1992, ISBN 0-87857-990-7.
"Worm Composting and Mulches", EcoGardener, Acres,
USA, March 1996
"The Many Benefits of Mulching", Malcolm Beck, Garden-Ville
Inc., Copyright 1996ÅNew research on the additional
benefits and qualities of Native Mulches.
Native Mulches are available from Nature's Way Resources, located at 101 Sherbrook
Circle in the Woodlands area.