BUILDING GREAT SOIL


Building a Compost Pile                        

 

            There are various approaches to building and containing a compost pile.  The ideal ratio (by weight) of carbon to nitrogen is 30:1, which can normally be approximated by adding equal volumes of carbon-rich material and nitrogen-rich matter.  

             

Compost piles:  in a pit or trench or in a pile or in a container

  • The pile should be a minimum of 3’ x 3’  
  • Loosen the soil beneath the pile to about 12 inches deep. 
  • Brown:  First add a 3 - 4” deep layer of heavier brown material, like twigs  and other woody material,  corn, sunflower stalks, and other coarse vegetable stems.
  • Soil: Then add a 2” layer of soil. 
  • Brown:  Follow the soil layer by a 3-4” layer of brown material that is carbon-rich, like dry leaves, straw, a few pine needles, and other dry vegetation. 
  • Green:  Next, add another 2” layer of soil, then a layer of green vegetation like grass cuttings, plant cuttings, and kitchen wastes. The green layer and manure add nitrogen to the pile to feed the microorganisms doing the composting work. 
  • Manure: Animal manure can be added between the green layers and the dry layers, or a small amount spread over each layer. Repeat the layers as you build your pile. 

 

Avoid meat and dairy –  will attract animals and smell bad

Keep moist but not soggy – don’t drown the microbes who are doing the work!

Turn in 3 – 6 weeks, can age 1-2 years

A pile works fine without a container… keep it built and shaped after you turn it or after adding new materials in order to maintain bulk and heat and moisture…

 

There are various types of containers that can be used: can help the pile from becoming unruly.

 

--Wire bins –  welded wire or woven wire fencing, chicken wire or hardware cloth.

Wire bins lose more heat than solid containers, but can be covered with plastic.  Wire can be supported by a wooden frame:  for convenience try  2  L-shapes that hook together and that can be unhooked and moved so the pile relocated  as it is turned. Or, the wire can be supported by metal t-posts hammered into the ground.   36” is a good height for the wire, and a diameter of 3 ½ feet works well.  Hardware cloth will stand alone without support if it’s in the 3 -4 foot diameter range. 

 

--Metal panels – 2 or 3 or 4 feet wide clipped together to make a cage, can be easily cut with tin snips. Feed stores often have a variety of metal panels

 

-- Wooden boxes made of untreated wood, 1x6’s supported by 4 x 4’s

Usually a box has no top or no bottom, and has a removable front made of boards that slide in and out between  4 x 4s

 

--Bins made of concrete blocks or straw bales.  If the concrete blocks are on their sides, the holes help with ventilation and aeration.

 

--Barrels and drums – 55 gallon drums and barrels, chemical-free

--Commercial bins and tumblers.  Tumblers are usually mounted on a frame to be rotated easily.

 

 

 

 

COMPOST:   BLACK GOLD

 

Simply put, there’s nothing like compost if you want to build healthy soil.  Making compost is recycling, it’s a great excuse to be outdoors getting exercise, and your plants and soil will be loving it. And, perhaps best of all, when you make it, compost is free.  Let’s take a look at what makes compost happen, and how it benefits you and your soil.

 

What Makes Soil Healthy

Humus is the end product, the transformation product, of composting, by microorganisms, insects (e.g. beetles and termites), and worms in nature, or with your assistance in a well- maintained pile.  Soil is fertile because of the presence of humus that is generated by the community of soil organisms. Humus gives soil its dark brown or black color and crumbly soft texture. When the organisms in the soil decompose plant and animal material, humus is the material that remains with their droppings and decayed bodies, along with the partially or completely decomposed plant and animal material. Humus itself is quite resistant to further decomposition.  Humic substances, the active materials in humus like humic acids and fulvic acid, capture nutrients and allow the nutrients to be available to plant roots.  These compounds combine with micronutrients and transport them into plants. Humus also increases the ability of soil to retain water.  Compost provides this life-giving humus to the soil.

 

Compost in the Soil

Compost provides organic material and nutrients to the soil. Mulch is applied to the surface of the soil; compost is layered on the surface or worked in.  Mulch applied one season becomes the compost for the next season.   The amount of compost to be added depends on the desired goal and plants involved.  For example, the soil may be highly amended, 50% or more, for veggies that have a quick and short growing season.  Less amendment, 20 – 30%, is adequate for larger plants like trees and shrubs, to best support growth in native soils as the root zone expands. A shallow layer of compost may be spread on the surface several times during the growing season.

 

Building a Compost Pile

THE INGREDIENTS 

It’s the microorganisms in the pile that are driving the decomposition process, so all the necessary ingredients for the microorganisms to grow, multiply and do their work must be provided. Actinomycetes, a type of filamentous bacteria that resembles fungi, are the main microbial composting helpers and create the web-like matrix you see in the pile. The microbes need four ingredients:  1) an energy source, carbon; 2), a protein source, nitrogen; 3) oxygen to breathe – if oxygen is lacking, decomposition may slow down by as much as 90%; and, 4) moisture, just the right amount- not soggy, but like a damp sponge.  As long as these components are there, with the ratio of carbon to nitrogen about 25 or 30:1, the bacteria will do their work.  To get this ratio, for every 100 pounds of carbon material, add about 2-3 pounds of nitrogen matter. 

 

THE STRUCTURE

There are many approaches to building and containing a compost pile. Compost piles can be in a pit or trench or in a pile or in a container and should be a minimum of 3’ x 3’. Various types of containers are useful.  A container can help the pile from becoming unruly and to maintain a good shape to hold the heat. Concrete blocks and straw bales are relatively inexpensive. If the concrete blocks are on their sides, the holes help with ventilation and aeration.  Wire bins can be made of welded wire or woven wire fencing, chicken wire or hardware cloth. Wire bins lose more heat than solid containers, but can be covered with plastic. Hardware cloth will stand on its own without support if the diameter is around 5 feet or less. Metal panels, 2 to 4 feet wide can make a cage.  Wooden boxes are attractive; untreated 1x6’s supported by 4 x 4’s are convenient. Usually a box has no top or no bottom, and has a removable front made of boards that slide in and out between 4 x 4s. Fifty five gallon drums and barrels that have not had chemicals in them are also useful.  There is also a variety of commercial bins and tumblersBins can be opened from the bottom, or have no bottom so that the compost is scooped out of the bottom.  Tumblers are mounted on a frame and can be rotated. Often there are holes on the sides for aeration.  The limited volume of tumblers can be problematic:  usually the capacity is not more than 1 cubic yard, which will probably not get up to temperature for hot composting.  Bins and tumblers can be used selectively for leaves, grass clippings and kitchen waste, then this material transferred to a larger pile.

 

BUILDING THE PILE

Loosen the soil beneath the pile to about 12 inches deep for aeration and to help hold moisture.  First add a 3 - 4” deep layer of heavier brown material, like twigs and other woody material, corn, sunflower stalks, and other coarse vegetable stems. Then add a 2” layer of soil, if available  Follow with  a 3 – 4” layer of brown material that is carbon rich like dry leaves, straw a small amount of pine needles, and other dry vegetation.  Next, add another 2” layer of soil, then a layer of green vegetation like grass cuttings, plant cuttings, and kitchen wastes like fruits and vegetables. The green layer and manure add nitrogen to the pile to feed the microorganisms doing the composting work.  Manure can be added between the green layers and the dry layers, or a small amount spread over each layer. A sprinkling of humates can be added at any point. Repeat the layers as you build your pile.  Avoid meat and dairy that may attract animals and smell bad.

 

Keep the pile moist but not soggy – don’t drown the microbes doing the work!  Once the pile heats up, turn it in several days, or wait 3 – 6 weeks in cooler temperatures. Add new materials to maintain bulk, heat and moisture. If you have a very large pile (more than 8’ x 8’) the pile may need to be turned twice a week for aeration.  Your compost is ready to feed your soil and nurture your plants. The aroma of a finished pile will be earthy and sweet. The texture should be even and uniform.

 

The Temperature Factor

The internal temperature of the pile is a determining factor for how long total decomposition of the pile takes, and how fast you actually have useable compost.  Long-stemmed compost thermometers can be obtained on line. Composting styled according to differences of temperature is referred to as ‘hot composting’ and  ‘cool composting’.  There are three categories of bacteria doing the work in the compost pile, grouped according to their preferred temperatures. The internal temperature of the pile will increase due to microbial activity and also to higher ambient temperatures outside. New species of bacteria will begin to grow and multiply in the warmer environment.  Also, as other conditions shift, like moisture or pH, additional strains will begin to appear.

 

Psychrophiles are the first onslaught of bacteria in a pile.  They work at around 55 degrees F, and can work more slowly at 28 degrees. These bacteria work on the organic matter in the pile and release nutrients in the form of amino acids, the building blocks of proteins.  As they work on carbon compounds, the carbon is ‘burned’ or oxidized, and the energy given off as heat.

 

Most decomposition in the pile is mesophilic, in the 70 – 90 degree range, though mesophiles can be happy from 40 – 110 degrees, and can be highly efficient composters.  Actinomycetes are mostly mesophilic.  So even if your pile doesn’t heat up to the max of 140 – 160 degrees, very efficient decomposition is still taking place.  If a pile were started in the summer months, the psychrophiles would hardly be active, and the decomposition would begin right away with the mesophiles.

 

Thermophiles  are the hot-shot composters,  and if they generate too much heat, they will roast themselves right out of the pile.  Thermophilic activity begins at an internal temperature of around 100 degrees. Once these bacteria take over, the temperature will go up to 160 degrees.  Unless the pile is feed and turned, this peak temperature will last less than a week, maybe 3 – 5 days.  This amount of time is adequate for these bacteria to do what they need to do, and it is during this hot period when toxins will be broken down, stray seeds killed, and pathogens killed.  During the hot period of composting, earthworms and other beneficial creatures will migrate to the outer perimeter of the pile where the temperature is cooler and more to their liking.

 

A gradual drop in temperature does not mean that the compost is finished, but that the mesophiles will become active again.   All three groups of bacteria will continue the decomposition process at some level until all the organic matter is consumed, or until there is no oxygen, or no carbon or nitrogen.  Inactive bacterial spores will remain until the conditions are right again.

 

Along with the different bacteria that are processing the compost, other organisms are working as well.  Fungi working at various different temperatures are breaking down cellulose and lignin, along with the cool- temperature bacteria.  Thermophilic fungi appear in the pile 4 – 6 days after the pile is built.  At cooler temperatures, the decomposition will eventually happen, but if your piles are not really heating, be prepared to wait a couple of seasons for finished compost.  Also, not all noxious weed seed may have been fully baked, nor plant pathogens.  Also, it can’t be assumed that toxins are totally broken down- i.e. toxins like residual agricultural chemicals that may have contaminated your soil at some point may still linger around.  The breakdown of toxins is due to a combination of heat as well as to particular strains of microorganisms. 

 

Your finished compost is truly black gold.