Throughout history, man has used manures, fallen leaves,
grass clippings, wood chips and many other natural materials for mulch in the
garden. There are so many more types of mulch than this article can elaborate
on, so we will cover the types that may be most readily available. The mulch mobile is filled and ready to head out to the vegetable garden.
It is a well-known benefit that mulches help
to retain even moisture in the soil, so that plants are not going through dry
periods between watering. Mulches are
also known for their ability to slow down weed growth and for those weeds that
do make it through the mulch; they are easier to remove from the garden soil. Here's a photo of pine shavings used as a mulch on newly planted Blackberry plants.
Although living mulches are also known as cover crops, green
manures or catch crops, these will not be discussed in this article. Plastic mats and rolls,
rocks and ground up rubber tires, and similar mulching products, will also not
be discussed here. This article will cover mulches that you can turn back into
the soil after use.
Mulches make the garden look clean and neat; they keep soil
off of garden vegetables that grow on or near the ground. Once the mulch has done its job for the
season, they are simply turned into the ground, and add to the soils tilth and
structure. In addition, when mulches become part of the soil, they add nutrient
and microbial activity to the soil as they break down.
Mulches can break down very rapidly, or they can stay in the
same spot for years, returning to the soil very slowly. An example of mulch that breaks down quickly
is finished compost.
Compost that has been allowed to complete the composting
process, cool down to acceptable and usable temperatures, and be run through a
fine mesh screen can be used as mulch at about three inches thick. It will
break down within one season. This application may also be considered a side
dressing for the benefit of nutrient in the compost.
On the other hand, mulch that lasts for an extended period
of time in the vegetable garden might be something like wood chips. Unless the
chips are shredded down into very small particles, they will take more than one
season to break down. The bulkier the material you use, typically the longer it
will take to return to the soil. Leaves will break down fairly quickly;
however, shredded leaves will break down faster.
There are other considerations when using different types of
mulch in the garden. If you use fresh manures as mulch directly under the
plants, you are likely to burn your plants. Some manure is better left to dry out
or to be composted prior to use. Chicken
manure is considered hot and will certainly do damage to your plants, so
compost it first. Rabbit manure is considered a "cold" manure and can be added directly to your plantings.
Horse and cow manure may contain pathogens, so they should be
left to dry out for a season, or composted to kill off these
troublemakers. You can also turn manures
under in the garden in the fall and let them decompose all winter long.
Here are some quick notes and things to consider with the
following mulches:
Manure:
It’s best to compost it before use, or to let it rot. Cow
manure may contain a lot of weed seeds, so I always compost first. Horse manure
may contain microscopic worms and other pathogens, so I compost first or turn
under in the fall when I’m not growing anything. If you do decide to use horse
manure as mulch during the growing season, use no more than 3 inches thick, as
it will mat once it is wet, and will not allow water to penetrate very well.
Manures are also known for being the cause of E.coli. All vegetables harvested
from areas in the garden that used fresh, or uncomposted manures must be washed
well prior to being eaten. When you work with any kind of manure, you should
always wash your hands well before coming in from the garden.
Straw:
Straw is excellent mulch, and does a great job at retaining
moisture and keeping the garden area relatively free from weed growth. This
material is very high in carbon, so it may take away nutrient from the soil as
it breaks down. I usually spread a high nitrogen fertilizer prior to placing straw
mulch. Once the season has ended, straw mulch can be turned under and left to
decompose through the winter months. You can usually find straw at your local
feed store for a low enough prices that justify its use.
Here's my YouTube video on using straw mulch
Grass clippings:
Grass clippings are full of nitrogen and break down quickly.
I never use more than three inches of this kind of mulch, as it will mat down
and may eventually begin to smell bad. Use only cool season grasses as mulch.
If you use Bermuda, or any other trailing type of grass clippings, you are
bound to grow a nice lawn in your vegetable garden, and you don’t want that. I
try my best to keep any kind of grass clippings out of the garden and out of
the compost; unless I’m certain that they are a cool season type like fescue or
rye grass.
Wood chips:
Wood chips are also great as a mulch to use when you need
one to keep the weeds to a much reduced level. They are also very high in carbon, and take a
long time to decompose. Fertilize prior to applying this mulch around your
fruit trees. I’ve connected with multiple sources that provide me with an
endless supply of wood chips for free.
I try to keep a pile in the back yard
all year long, so I have them on hand when I need them. I turn them under
in new garden plots that I won’t actually be using to grow vegetables for a
year or so, to add tilth to the soil. When mixed with horse manure and turned
under, they break down very well over the winter months.
Leaves:
Leaves also make excellent mulch. Most leaves can be used
directly as mulch in the garden. Avoid
using sycamore leaves unless they are shredded and composted first. Shredding
leaves first avoids any matting of leaves and also helps to avoid any diseases
brought on by matted leaves. Eucalyptus or Oleander leaves are also not good
mulch. Do not use these in your vegetable garden.
Pine Needles:
Although I’ve used pine needles in the past, they just are
not available to me here in the Dallas, Texas area. I would typically use them
in the landscape rather than the vegetable garden. I would compost them before
mixing that finished compost in my garden.
Pine needles are known for adding acid to the soil, but you’d have to
add the needles for many years to have even a small increase in the amount of
acid in the soil, so just add them to your compost pile when they are
available.
There are so many more types of mulches available to you in
your area. Give them a try and see what works best for you. Remember, just like
it is important to use a variety of plant matter and manures in your compost
heap, it is equally important to use a variety of mulches in the garden, You
will be providing a variety of nutrient to the soil when you turn the mulch
under.