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Compost - How To Make It
BACKGROUND - Composting is the
process of breaking down plant matter with bacteria, fungi, and
protozoans. Also insects and earthworms join in the process
once the compost pile cools down. These living organisms need
carbon, nitrogen, water, and air in the right proportions. Too
wet and the pile ferments (and stinks!). Too dry and the pile
does not decompose. The ideal ratio of carbon to nitrogen is
from 25:1 to 30:1. The table below, taken from data listed at
Texas Cooperative Extension and Ohio State University
Extension web sites, gives ratios found in common composting
materials.
| Carbon:Nitrogen
Ratio |
| Food Waste Products |
15:1 |
| Sawdust, Wood, Paper |
400:1 |
| Straw |
80:1 |
| Grass & Lawn Clippings |
15:1 |
| Leaves |
50:1 |
| Fruit Waste Products |
35:1 |
| Rotted Manure |
20:1 |
| Cornstalks |
60:1 |
| Alfalfa hay |
12:1 |
| Fresh Poultry Manure |
10:1 |
| Fresh Cow Manure |
20:1 |
| Fresh Horse Manure |
25:1 |
As you can see, too much wood,
sawdust, or paper can give you a ratio too high in carbon. This pile
may not "take off" for you. Conversely, a pile with a low
carbon to nitrogen ratio can decompose so quickly that the excessive
heat can burn your compost and kill microorganisms. This is
why a pile with only fresh grass clippings will get very hot very
quickly and produce burning. You should always layer grass
clippings with old compost and brown matter. The bulky brown
matter, besides being needed to counter balance the low
carbon:nitrogen ratio of grass clippings, also serves to "bulk up"
the pile, allowing good air circulation. The keys to a good
heap are: a variety of ingredients, some old compost or rotted
manure to act as a "starter", air that get to the sides and bottom,
enough volume so moisture and heat can be retained but not so big as
to seal off the middle (3'by3'by3' up to 5'by5'by5'), and proper
moisture content.
Steps For Making a Compost - How To Make
It Work!
STEP 1 - You should
have a compost bin system that allows you to get the air to the
bottom and the sides. A side-by-side bin like the one shown
below will allow air to get to all layers since the air can get in
from the sides and the drain hose at the bottom also allows air in.
With two bins, you can easily turn the pile by transferring from one
bin into the other. The bins below hold a total of about 96
cubic feet of compost - that's a lot but if you do a lot of
gardening you will use it! Free
plans for building these compost bins are at this link.
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Click on photo for larger view.
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Click on photo for larger view.
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STEP 2 - Lay some
coarser drier matter at the bottom of the pile. You can place
dead branches and then old dry leaves at the bottom. Branches will
help keep the air circulating at the bottom and they will decay
fairly quickly if they are not too large in diameter.
Click on image for larger view
STEP 3 - Place a thin
layer of finely chopped green matter. Grass clippings work well -
just don't make your whole pile grass clippings since they tend to
seal off the air and generate excessive heat. The heat can
then kill the needed microorganisms and even halt the decomposition.
Click on image for larger view
STEP 4 - Place a layer
of well rotted compost on the grass to get things started. If
this is the first compost pile, you should purchase several bags of
compost or manure from a garden store or find a rural neighbor that
has a small amount of rotted manure they can let you have.
Click on image for larger view
STEP 5 - Place another
layer drier leaves or dried grass. The leaves should be aged
somewhat (the ones shown were sitting in a pile 8 months), or
chopped up with a mower. Lawn clippings tend to not seal of
moisture so much if they are allowed to sit in a pile for a week
before being placed into the pile. The lawn clippings shown
below were in a pile for about 1 1/2 weeks before being placed into
the compost heap.
Click on image for larger view
STEP 6 - Place a layer
of kitchen waste (or more chopped green matter or grass clippings or
fresh cow/sheep/horse/rabbit manure).
Click on image for larger view
STEP 7 - Place another
thin layer of rotted manure or old compost.
Click on image for larger view
STEP 8 - Place a layer
of brown matter or leaves. The leaves shown below were sitting in a
pile for 8 months.
Click on image for larger view
STEP 9 - Place another
layer of kitchen waste or fine green matter.
Click on image for larger view
STEP 10 - Continue
placing layers alternating between your compost starter (old compost
or manure), your nitrogen-rich green-clippings/food-wastes or fresh
manure, and your loose drier brown matter that has the higher carbon
content. Get your heap to a height of at least 2 feet.
In the photo below, this heap is almost 3 feet high. For your top
layer, use the old compost or manure to help hold the moisture in.
Don't make the dry brown matter your top layer since it will quickly
dry out. Water your heap with a garden hose so it is the
consistency of a wrung out sponge. After a week or two, turn
the pile or transfer into the adjacent bin. After about 3
weeks to a month or so of proper composting, the compost pile will
cool and it will be ready for garden use.
Click on image for larger view
I made my bins at the
downside of a shed roof so the rainwater off the roof gives my
compost a good watering. I rarely have to water my compost.
The heap constructed for this page started to heat up by the next
day.
More Free Plans and
Ideas Below!
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