Fall leaves: They're a goldmine of mulch, compost
By: Mark Bowen
leaves have already started falling around my house, so I am
eyeing spots in the landscape that need mulching. I always think
it's such a shame when I see homeowners with lots of trees using
store-bought bark mulches on their landscapes in early to
mid-fall. What usually happens next is the leaves start falling.
Then as they are raked off or blown off, the leaves are often
wasted and much of the store-bought mulch ends up being raked
off or blown away little by little, prompting yet another
expenditure of time and money for more mulch.
There really is a better, more frugal way. If leaves are allowed
to fall first before any supplemental mulching occurs, then you
can spread them around so beds have an average leaf mulch layer
of 3-4 inches. If you still have extra, fill up to eighty
percent of a compost bin with leaves or start a new one. And if
you still have extra, you can store them in perforated trash
bags until more are needed in the compost or on your landscape
Now I know that some people are not wild about the look of
leaves in highly visible areas. If you are in this camp, you can
always top off the leaves with a couple of inches of processed
native mulch. This recycled mulch is practical and attractive.
By topping off the leaves with mulch, the end result will be
that the leaves will eventually break down and enrich your soil.
If all of your leaves fall, and you do not have enough of them
to mulch all of your beds, by all means purchase some native
mulch for supplemental use.
It can be a challenge to deal with leaves when they are coming
down steadily or all at once. However, there are some strategies
to consider when working with leaves.
Leaves are rich in nutrients. Most leaves are rich in
potassium and micronutrients. These nutrients can be returned to
the soil and eventually your plants if the leaves are used as a
mulch in landscape bed or groundcover areas.
Leaves can save you money. Your leaves can often be left
alone in beds, certain types of slightly open groundcover areas,
or they can be spread around in a manner that results in a three
to four inch layer of leaves being left in place as a mulch.
Most shrubs and trees will benefit from a 3- to 6-inch layer of
leaves as mulch. It often makes sense to keep leaves or bark
mulches from piling up too thickly around the center of disease
prone plants such as azaleas. A small fortune can be saved over
the years by using leaves as mulch rather than disposing of
them. You also might consider converting lawn areas routinely
overwhelmed by leaves to groundcover areas that will be more
tolerant of leaf layers.
Lawn areas. A light layer of leaves can sometimes be
ground up with a mulching mower and left on the lawn. This
practice can be effective as long as the leaves are ground fine
enough and the quantity is modest enough to not smother the
lawn. Excess debris can be relocated and added to beds or
compost piles. It is important not to lower your mowing height
in the hopes of making it easier to grind leaves. Lawns will
handle hard freezes better if not cut too short (less than 3 1/2
inches) during winter months.
Compost extra leaves. Compost as many of your excess
leaves as possible. Leaves make an excellent compost ingredient
due to the carbon, potassium and micronutrients they provide.
Even if composted alone, leaves will eventually decompose into a
valuable dark earthy material known as leaf mold compost.
Alternatively, carbon rich brown leaves can be mixed with
nitrogen rich materials such as animal manures such as turkey or
chicken (not cat or dog), green grass clippings (when that time
rolls around again), coffee grinds (one to two percent nitrogen
content) or vegetable waste. As a general rule, mix six to eight
parts of leaves with one part nitrogen rich material.
Open-air galvanized or plastic coated wire compost bins can be
purchased from area plant nurseries or garden centers, or you
can make your own with materials from the hardware store.
Several area municipalities also sell compost bins cheaply to
minimize the hauling away of leaves from the curb. Visit CE
Shepherd's Web site
information on their inexpensive complete composter. This is a
local company that sells them at wholesale-type prices.
Since compost piles shrink rapidly, the stored leaves will come
in handy for filling in your compost bins as space becomes
available during the early stages of composting. A three bin
composting system works best if space permits, and it will allow
you at any given time to have one pile ready to use, one pile
working and one pile ready for the addition of new materials.
Join us as we build a compost bin at Westbury Community Garden
and learn how to build your own. Our Hands-on Backyard
Composting & Maintaining Healthy Soil is held on November 12,
3:00 – 5:30 pm.
Urban Harvest Classes Calendar
Using compost. Finished compost can be added as needed to
landscape beds and vegetable gardens or it can be screened and
used as a topdressing over lawn areas to restore soil health.
Compost contains large quantities of beneficial microbes useful
in fighting off diseases and some pests. The microbes also help
make nutrients available to your plants. Additionally, leaves
used as mulch or compost provide a habitat for helpful
macro-organisms such as earthworms and ground beetles. Ground
beetles love to eat slugs and snails.
Tannic acid. It was once thought that leaves should not
be left on the ground or composted due to the possibility of the
tannic acid in leaves compromising plant health. The funny thing
is that most of the bark mulches that were used instead are also
rich in tannic acid. The reality is that in healthy soils, the
humus (organic matter that has been digested by microbes) helps
to buffer tannic acid and makes this issue a moot point. The
exception can occur if naturally occurring beneficial microbes
are routinely suppressed through the use of harsh chemical
If your leaves are not eventually breaking down into humus by
microbes, then your soil may benefit from being treated with a
microbe inoculant product such as Microgro or compost tea to
restart the natural decomposition process that should be
Compost tea can be made by placing finished compost in old
stocking and then letting it soak in a five gallon bucket of
non-chlorinated water for a couple of hours. The tea that
results will be rich in microbes and micronutrients. Note to
men: be sure to ask for permission before assuming your wife's
stockings meet the "old" definition. I am writing from
experience here, although I am far from trained.
Acidity. Another myth that has kept some people from
taking advantage of leaves in the past involves the mistaken
notion that acidic leaves will cause pH related problems for
plants. The same natural decomposition process that helps turn
leaves into humus also helps moderate pH levels. For example,
finished compost will more often than not be only slightly
acidic to slightly alkaline. As long as the microbes that occur
naturally in your soil are not being suppressed with harsh
products, they will do their job of turning the leaves into
humus, a process that will keep the possible pH impact of leaves
from being a problem.
Mark Bowen is Executive Director of the non-profit Urban
Harvest, Inc. For more information about community gardens,
classes, school gardens and farmers markets, visit