"How Do I Compost?"

Compost is decomposed organic matter. And it's a major part of providing nutrients for your crop and keeping a garden system sustainable. It doesn't have the nickname "black gold" because it's worthless. If you intend to start growing your own food, you best know how to compost. Luckily, it doesn't require much work and it's really easy. All it takes is some basic knowledge, patience, and the occasional period of shoveling.



Where To Put The Compost Pile

The compost pile should be:

  • In an open area that will receive rainfall
  • If you live in a hot climate, out of direct sunlight (drys the compost out)
  • Shielded (at least partially) from wind (drys the compost out)
  • Away from flammable things (aerobic compost can get very hot and, though rare, fires can start)

Not necessary but worth considering, it would be nice if the compost pile was:

  • Near a water source
  • Near where you're applying the compost to make travelling distances shorter
  • Out of sight if you have neighbors that don't appreciate compost piles

Under a deciduous tree is a good place. It will keep it shaded in the more intense heat of the summer, allow rainwater access, and during the fall it will leave lots of brown material (leaves) nearby. Keep it at least 6 feet from the trunk of the tree, any closer and you might encourage infestation problems.

You can build the compost pile on an empty garden bed and leave it to decompose there. Any nutrients leaked from the pile will end up the soil. This is the primary practice of lasagna gardening

You can also dig uncomposted materials about 1 foot into a bed and leave it to break down. The nitrogen will not drain out because it will be tied up in the decomposition process. Do not plant in the bed for 3 months; this is best done over winter. This is usually referred to as trench composting.

How To Build Compost
To make compost you need a carbon material (brown), a nitrogen material (green), water, and, depending on whether you are hot or cold composting, oxygen.

The general method for building a compost pile is: lay down some brown material; lay down some green material; add a thin layer of soil; spray with some water; and keep repeating layers in that order. You want to keep a ratio of about 45-50% brown, 45-50% green, and 5-10% soil. Proper ratios are important because too much carbon decreases nitrogen availability and too much nitrogen decreases carbon availability.

  1. start by loosening the soil with a shovel or pitchfork a foot deep where you plan to place the pile.
  2. place 7.5cm/3 inches of sticks and wood materials for air circulation and drainage.
  3. evenly lay out 5cm/2 inches of brown material.
  4. evenly lay out out 5cm/2 inches of green material
  5. cover with 0.6-1.3cm/0.25-0.5 inches of soil
  6. water the pile
  7. repeat steps 3-6 ad infinitum

These measurements don't have to be exact; they are guidelines to keep the ratio proper

If layering in a lasagna gardening style (on an unused bed), make sure all the layers are spread evenly across the bed and omit the bottom layer of sticks. After several months when the pile of organic matter has broken down, all you have to do is gently mix the compost into the top couple inches of the garden bed.

Pile building can be done all at once or done as materials become available. If you have an excess of brown, leave it off to the side. It doesn't hurt to have some excess brown lying around incase you have a sudden large input of green material. Green being harder to save and have it stay green.

If you are making compost in a bin, you don't need step 1, and 2 is optional (as long as the bin has some openings in the bottom for drainage).

Add manure sparingly. It's best treated as a separate fertilizer, thus dealt with separately.

How To Manage A Compost Pile

Compost is ready when it has a consistency similar to coffee grounds/good soil. It should be dark, crumbly, lightly moist and have a sweet, earthy smell.  Curing can take 1-6 months depending on many variables (how often it's turned, the temperature around the pile, the materials in the pile etc.)

Water the compost pile as necessary. A handful of compost should feel lightly damp, not soaking nor dry.

The usual goal is hot (aerobic) composting, which speeds the decomposition process, kills weeds and pathogens with the high temperatures (as high as 160 degrees fahrenheit), and greatly reduces the smell. The key to hot composting is oxygen, so the pile will need to be turned at some point to aerate it. If you're feeling super dedicated you can turn the pile every couple days to a week to maximize the aerobic process, but turning only once a month or even just once during the entire curing is acceptable. The more you turn, the faster it breaks down (if turned every other day, you can fully cure compost in only a few weeks). The pile must be at least 2 cubic feet for aerobic to possible. Before turning let the compost sit at least 4 days.

When you turn a compost pile, don't just flip it. You want to switch the outside and inner parts of the compost pile. So remove the outer layer of the pile, create a separate pile with it, and pile the inner layer on top of the former outside layer.

Cold composting is what happens when you don't turn the pile. It will take a lot longer than hot, and gives off a strong smell (a product of the bacteria involved with cold composting). It requires less attention (you don't turn it) than hot composting. There are ways of making cold work, but why would you want to when hot is obviously so much better?

What Can You Compost?

Pretty much all plant based material.

Green refers to fresh plant material. Things like: grass clippings, fresh weeds, vegetable scraps, fruit scraps, coffee grounds, garden wastes, green manures/cover crops

Brown refers to dry, aged plant material. Things like: sawdust, shredded newspaper, corrugated cardboard and egg cartons, straw/hay, dried leaves, dried kitchen scraps

Avoid adding branches to any layer of the compost (except the very bottom) because they take forever and a day to break down compared to things like dry leaves and watermelon peels.

What Can't You Compost?

  • infected plants
  • poisonous plants (oleander, hemlock, castor beans)
  • plants that take a long time to break down
  • plants that have acids toxic to other plants (eucalyptus, california bay laurel, walnut, juniper, cypress)
  • plants that are too acidic (pine needles), unless you want to create acidic soil for something like strawberries
  • ivy and succulents which may not be killed in the decomposition process
  • pernicious weeds (wild morning glory, bermuda grass)
  • cat and dog manures
  • meat and bones (these are handled separately)

How To Use Compost
Is a description even necessary? Before starting a crop, no more than 1.25cm/0.5in of cured compost should be gently and evenly incorporated into the top couple inches of the soil using a garden fork. And if possible before each additional 4-6 month crop.

If you want to store cured compost, spread it out somewhere where it won't get wet and let it dry out. Once it's dry, store the compost in a sealed container.

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