What is Compost?
Many home gardeners seem to agonize over composting,
making it much harder than it really needs to be. Composting at home is quite easy and anyone
can do it successfully. Compost is like
black gold for your plants and it helps the environment too. Like anything else
there are various methods of home composting and I’ll discuss a few of them
here.
Compost is simply organic material, anything that was
once living, that has been broken down by microbes and soil creatures such as
earthworms into a substance very similar in looks to fluffy soil. Nature makes
compost all the time; it’s called rotting when nature does it. Leaves rot, a fallen tree rots, and apples on
the ground rot. Basically, when you do
home composting you want your yard waste and home garbage to rot.
Compost is not fertilizer, although it does return
nutrients to the soil. It is not soil,
soil has a base of broken down rock with organic matter added. Eventually the fluffy material you produce
from home composting will disappear, rotting down to pieces so small that it
mixes with the soil, a very desirable thing.
It’s then called humus.
Why do home composting?
When you do composting at home you save all the wonderful
nutrient value and soil amendment qualities of your waste and return it to your
garden while saving space at the landfill.
You save money at home because you won’t need as much fertilizer. Experts at Michigan State University say that
if you leave the grass clippings when you mow and allow them to decompose, you
can skip one application of fertilizer.
This is a natural form of composting.
If you have poor soil, either sandy, heavy clay or
nutrient poor, then composting at home can take many of the things you might
throw out and turn your garden soil into something rich and desirable. There is nothing better for soil than organic
matter and compost is organic matter that has been partially broken down.
If you do composting at home, you won’t be spending all
that time bagging yard waste and taking it to the curb. Some communities have passed a law
prohibiting mixing yard waste with other trash.
You might have to haul it away yourself or pay for a separate collection
if you don’t compost it at home.
Methods of Composting
Nature practices sheet composting. A layer of leaves falls on the ground beneath
the trees and lays there to rot. You can
do this too. Don’t rake your leaves, run
over them several times with the mower when they are on the lawn and let them
stay where they are. Let them blow into
flower beds and stay there. You can also
spread your organic waste over the garden and just let it rot.
For many of us though, a layer of rotting garbage under
the roses just doesn’t look right.
That’s why we make compost piles.
If you live in the country without close neighbors just make a pile for
your organic waste. It will eventually
rot down to compost. This is called cold
composting.
If you live close to neighbors and don’t have much room,
you want a small compost pile that rots quickly and without much smell. This is
called hot composting, because the decaying process will heat up the pile. When composting at home you can buy or build
a number of items that will speed up the decaying process and hide what you are
doing
Compost barrels or compost tumblers take small amounts of
organic matter and rot them in a matter of weeks. Turning the compost makes it rot faster and
these compost barrels or compost tumblers make that easy. You’ll find them for
sale in garden catalogs and stores.
You can also make or buy compost bins. These are just devices to hold small piles of
organic matter which you will turn over with a shovel or pitchfork from time to
time. You can make them from old pallets, a circle of wire, slats of wood or you
can buy various bins on the market for home composting.
The disadvantage of compost tumblers, barrels and bins
for composting at home is that they make only small quantities of compost at a
time and you may need several to handle your waste.
Hot
composting
In hot composting you want the pile to heat up quickly to
around 150 degrees F. and remain that way for a couple weeks. Hot composting makes finished compost faster
and the heat caused by the decomp process kills some weed seeds and disease
organisms.
You have a better chance of achieving hot composting if
you do these things: make smaller piles- no more than a few yards of compost
material, chop materials into small pieces, use at least 1-part green or moist
material to 2 parts dry or brown matter, don’t layer but mix ingredients thoroughly
and turn the pile once a week.
In some instances, you can have finished compost in 3-4
weeks with hot composting. Very small
piles may finish even sooner. But it’s
sometimes hard to get a pile to heat up and stay heated for proper hot composting. Don’t worry, this compost may take longer but
will be just as good.
Adding
compost starters
It’s not necessary to add anything to get compost
started, despite all the hoopla and sales pitches out there. You don’t need microbes or anything but the
proper ratio of greens and browns.
Nothing you buy will give you better or faster compost so don’t waste
your money. Don’t add other home
products like Epsom salt, sour milk, lime, and so on either. Some of these may impede the decomposition
process.
If you really feel you must add something to get your
compost started simply dig up a shovel full of garden soil and add that. It isn’t necessary, but it makes some people
avoid the magic potions being sold to make compost.
What to Compost
If you want to make compost quickly and without much
smell, you want to put in equal amounts of juicy (green) matter and dry (brown)
matter. Compost needs to be moist to
begin the decomposition process but if it is too wet, it will smell. If you are managing a compost pile you may
want to store some dry matter for times when you have a lot of juicy garbage.
Things that can used for composting at home include lawn
and garden waste, which includes grass clippings, weeds, leaves, pruned
material, dead plants and other things.
It can also include household waste such as vegetable peels, coffee
grounds, egg shells, rotted fruits and vegetables and some food scraps. You want to avoid putting meat, grease and a
lot of sweet food waste into the compost pile.
These attract animals and smell.
You can also use shredded paper, any paper except glossy
colored pages. That’s a good way to deal
with junk mail! If you have manure and
used bedding from farm animals, or straw and hay, pile it on. Don’t use manure from dogs and cats. This may carry parasite eggs and diseases
that are transmittable to humans.
Anything that was once living (and manure, which was
technically once living) can be composted, but don’t drag road kill home for
the compost pile. Farmers may compost
dead animals, but they have been trained how to manage this and they don’t do
it in the back yard.
The smaller the pieces that go into the pile the faster
it will decompose. Also turning the
pile over every week or so will speed up the process. If you have very dry weather and the compost
dries out it won’t decompose either.
Adding moist (green) matter or water can help.
If you notice a smell from your pile it is probably too
wet, or you have added meat scraps. You can add more dry material and/or
protect the pile from heavy rain with a tarp to dampen the smell.
Compost
tea
If you want to start an argument among horticulture
professionals just mention compost tea.
There are those that are positive it’s all bunk, those that think it’s
good for everything and those who feel it’s something between the two
extremes. Until recently I was one of
the people that felt compost tea was useless.
Then I came upon some research that made me reconsider my stance. I just spent several days reading more recent
published research on the topic and I have modified my position to some extent.
There is a lot of research on compost tea and when I talk
about research I am speaking about science-based research that has been
published in recognized professional journals and not popular garden magazines
and websites. This research can be hard to wade through and one must be careful
to not project what you want to hear/read about the topic onto the actual
results. You must also sort out
laboratory and controlled environment results from those obtained under average
garden or field conditions. I’ll give
you my opinion here based on my reading and I will also post some links at the
bottom of the article, so you can do your own reading and analyzing.
First let’s define compost tea. The oldest version of compost tea is just
putting some finished compost in a permeable bag of some sort- such as burlap-
and letting it sit in a barrel of water for a few days. The brown water that
results is compost tea. This passive method is often referred to as NCT. Some
studies also refer to it as compost extract.
But aerated compost or brewed compost is also being used
and complicated systems and equipment have been developed to make it. The systems involve bubbling air through the
compost-water mix. A number of additives
are also being pushed to make compost tea “better”. These include molasses, sugars of other
types, yeasts, and other concoctions.
Aerated compost tea is often referred to as ACT.
There are two major areas in which compost tea is thought
to be helpful, that of a fertilizer and growth aid and as a suppressor of
foliar, fruit and soil disease organisms.
The benefit is from the microorganisms, primarily bacteria, that compost
tea contains as well as nutrients that leach from the compost into the water.
So, does compost tea work? The answer seems to be- it might to some
extent. If you are someone who doesn’t want to use- or can’t use - commercial
fertilizers or pesticides to solve plant problems compost tea may be of some
benefit to you. In research studies that compared compost tea application to
conventional fertilizer or pesticides the conventional products were almost
always more effective. And in many cases
compost tea often did not provide enough of a benefit to make using it viable
in commercial production. However,
compost tea might be helpful as a last resort for home gardeners who have the
time and like to experiment.
Before you get excited and rush out to brew compost tea
read on. Compost tea is so highly
variable that the same results can’t be predicted from batch to batch. What went into the compost, the conditions
the tea was made under, the water pH and many other things all contribute to
whether the compost tea will help, be neutral or even be harmful. And fancy equipment or any additive don’t
seem to make much difference in improving the usefulness of the product.
What went into the compost determines the tea
results. Better nutrient quality and
disease suppression seems to come from certain types of compost than
others. Vermicompost (compost made by
worms), compost made with manure and compost made with some kelp seem to be
marginally more effective than other types of compost, including those made
with so called super weeds and herbs.
More research needs to be done on this.
What you absolutely should not do is add supplements to your compost teas like molasses,
sugars, yeast and so on, despite popular garden magazines and sites
advice. These things are said to feed
the bacteria and increase the bacterial component of the tea. All compost will
contain some harmful organisms like salmonella and E.coli, but in normal
finished compost the numbers are low.
However, the addition of, molasses, sugars and other things may increase
the population of these harmful bacteria to levels where they can pose a health
hazard. Organic grower standards
prohibit the addition of these things to compost tea used on food crops and you
shouldn’t use compost tea made with supplements on food crops either.
The problem with compost tea is that one doesn’t know
what the bacterial content of the finished product is. (And no, you can’t look
at a batch under a microscope and determine what’s there, without a lot of
training or some very expensive and complicated lab equipment.) Some compost tea seems to inhibit the
production of flowers for example, and that may because of the bacteria
prominent in that batch of tea. One batch may kill harmful fungal infections on
plants and other batches made the same way may do nothing to control the
problem. It’s a crap shoot on what you’ll get.
The fertilization efficiency of compost tea is also
highly variable. At most it is a very
weak fertilizer. One use of compost tea
that seems to make some sense to me is using it to water seedlings in a
soil-less planting mix. You’ll add some
nutrients, some soil bacteria and if you have the right bacteria in your tea it
may help suppress the fungal disease called dampening off.
Using compost tea as a fertilizer for plants planted
outside in the ground is useless. Using
the compost itself is far more effective.
Whole compost will provide more nutrients and will contribute more good
soil bacteria to the soil than compost tea.
Either work the compost into the soil or apply it as mulch around your
plants.
Compost tea needs to be made and applied frequently to be
effective. It doesn’t store or ship well
so forget buying compost tea products in stores- they are pretty much worthless
despite marketing claims. Home gardeners
should not sink money into fancy compost tea brewers either. Research has found that some products that
help the tea stick to foliage might improve the ability of compost tea to
suppress plant diseases.
Compost tea may be helpful when you don’t have other
options and for some specialized uses.
If researchers ever isolate what bacteria in soil and compost provide
the most benefit and learn how to ensure that those bacteria and not useless or
harmful bacteria can be increased and used, then we may have a good, reliable,
natural control product from compost tea.
That hasn’t happened yet, but it’s a possibility in the future.
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