The
Many Benefits of Mulching
Study
and mimic the forest floor and the plants in their native habitat.
In areas such as rain forests, plants have a thick layer of mulch
around them. As much as six inches of plant debris is piled around
these lush plants. In desert areas, on the other hand, there is very
little mulch. Most plants require mulch between these two extremes.
Four inches of loose fibrous materials works well around trees and
shrubs. The finer and smaller the particle size, the thinner the layer
needs to be. Thick layers of very fine material block air to the roots
of plants. In their search for air the roots will grow up into the
mulch, which can be harmful to the plants if the layer of mulch is
not constantly maintained.
The
shredded branches from tree trimmings and large two-inch bark would
be considered a fibrous or loose mulch. Leaves or leaves mixed with
some grass clippings and one-inch size bark would be a medium mulch.
When using medium mulch, the layer should be about two inches thick.
One-half-inch and smaller materials, like fine-screened and double-ground
barks should be used thinner, only up to one inch. These tiny particles
quickly settle together and prevent air and water from penetrating
properly. This finer, smaller material should be used around small
flowers and vegetables. Note: Small, fine-ground, fresh pine bark
releases phonols, trepans and tannins that can be toxic to certain
plants and can slow their growth considerably.
The
mulch on the forest floor is never a pure product. Instead, it is
a mixture of grass, leaves, a few sticks or twigs, and a very small
percent of manure and dead animal life. The homeowner and gardener
will have an accumulation of material in similar ratios. If an abundance
of green grass clippings, kitchen scraps, manure or other high-protein
products accumulate; it is best to compost them before using them.
The compost can be put down under a fibrous, dry-brown, high-carbon
mulch. This duplicates the profile of the forest floor.
When
applying mulch around plants, cover as much of the root area as possible.
Do not pile the mulch up against tree trunks. It isn't needed against
the trunk and may do harm.
Mulch
is helpful in flower and vegetable gardens as a weed deterrent. Weed
seeds that blow onto bare earth quickly sprout and become a problem.
Weeds that blow onto mulched areas are less likely to sprout, and
weeds that come up through a layer of mulch are much easier to remove.
Although
it is mostly ignored, research and common sense has shown that a high-organic
content in the soil is needed for soil microbes to detoxify pesticides
after they are used and also to furnish the energy the microbes need
to make high-analysis fertilizers available to plants without the
fertilizer itself becoming toxic. Again, we discover another great
benefit and the importance of using organic mulches. The toxic materials
in pesticides and fertilizers kill the microbial life of the soil.
Mulch and the organisms that live in it can help reduce that toxicity.
MULCHING
THE LAWN:
The
Don't Bag It program and the new mulching lawn mowers are the best
and most natural things to do for the lawn. Why did it take so many
years to figure that out? Most lawns, however, would still benefit
from additional mulching. Naturally, you wouldn't use the same mulch
you put around flowers, shrubs, and trees on your lawn. One-half inch
of fine-screened compost applied in the fall or early winter after
the grass has stopped growing is a good mulch. Water in thoroughly
and you'll find the thatch improves dramatically. It never fails.
Even a fine horticulturist like Dr. Parsons found that mulching with
compost improved his lawn.
The
improvements to lawns from mulching with compost are very quickly
evident. The contrast between the mulched and un-mulched areas are
so visible that many people have brought me pictures of mulched and
un-mulched areas. They are amazed.
People
tell me: "My lawn stays greener in the fall and comes out earlier
in the spring ." "I have no freeze damage." "The
lawn is thicker, no weeds, no diseases." "I can fertilize
less or not at all." "I have fewer grub worms, no chinch
bugs." The one thing they all say is, "I water less."
Most tell me they water about half as much as they did before mulching.
Lawns
are our biggest water consumers, making them the most important place
to practice water conservation.
An
experience a friend of mine had illustrates the immediate water saving
of compost mulch on a lawn. When Jim moved to San Antonio, he spread
Dillo Dirt (sludge that has been composted with yard waste by the
city of Austin) over the lawn of his new home. At the same time, Jim's
neighbor was out spreading topsoil and fertilizer. When the neighbor
learned Jim had spread sludge, he wasn't too happy. Time went by;
the hot, dry season came, and Jim's lawn continued to look great.
The neighbor's lawn and all the other surrounding lawns began to show
late summer stress. Jim happened to meet the neighbor outside one
day and mentioned that his lawn looked better. The neighbor replied,
"Your lawn looks great, and my water bill is killing me just
to keep my lawn alive!" The neighbor told Jim that his water
bill had been in excess of $200 per month for the past two months.
Jim was slightly embarrassed to tell him that his own water bill was
$38 and $42 for the same two dry months.
The
two yards were the same size. Jim has a wife and two young daughters.
Four people were using water in their home; only the neighbor and
his wife were using water at their house. Jim watered every 10 days,
while the neighbor watered daily. Both lawns have the same species
of lawn grass.
The
neighbor's yard probably had no crumb structure, no humus, no beneficial
soil life, or root colonizing microbes. The grass probably had fewer
roots, which grew shallower, and the grass was more susceptible to
insects and diseases.
Jim's
yard probably has all the benefits and good things provided by mulching
and decaying organic matter I have mentioned earlier. But there is
more. Science now tells us that the carbon in humus-decayed organic
matter in the soil can attract moisture from the air on humid days,
and the mycorrhizal fungi can collect it and supply the roots of the
plants. Also, as the microbes break down organic matter, they release
carbon dioxide (CO2), which is slightly heavier than
air. The CO2 tends to stay low near the grass before
it finally defuses into the air. The green leaves of all plants feed
from CO2. They take out the carbon and release the
oxygen, which we need. When there is an abundance of CO2
for the leaves to feed from, they utilize water a lot more efficiently.
Conserving
moisture, slowing flood waters, slowing global warming, lessening
the need for pesticides, healthier plants, smothering weeds, saving
money, recycling materials considered waste-and on and on. And we
still have not yet discovered all the benefits of mulching.
In
order for mulch to perform all these miracles, it must continually
be decaying at the surface of the earth, so we must continually be
adding new layers on the top.
If
we just practice what we now know about mulching, we could cut the
pumpage from our aquifers and reservoirs by one half or more. Our
lawns would always be green and our springs would always flow.
The
Garden-Ville Method - Lessons in Nature