How to Use Our Compost Bin

compostFeatured

May 8

Written By Maria B

Taylor Street Farms has a compost bin that is available for use by our neighbors. We ask that you compost correctly and follow these guidelines.

Please chop all items into small pieces of 3" or less. This helps them break down in the bin.
No meat or dairy products
No animal waste
No plastic (includes wrapping ties or stickers)

Please watch the video below for more information on how to use our compost bins correctly.

Composting is one of the top ways to better your garden plants and benefit the environment. While composting is not the norm these days, our ancestors have been doing it for millennia. In a society that lives on instant gratification, composting can be challenging as gardeners oftentimes have unrealistic expectations of their compost outcomes due to lack of patience but the true secret ingredient to excellent compost is patience - it takes time!

However there are basic principles that should be followed to optimize composting. In the following post, here are some insights gained from the book “Compost: The natural way to make food for your garden” by Ken Thompson.

As composters, our desired end product is humus, which is composed of broken down organic material and produces the brown color we see in soil. Finished compost piles are much smaller than a pile of fresh kitchen scraps, grass, leaves, etc. as a lot of the original material dissipates as carbon dioxide, atmospheric water, and minerals. We can think of composting as replicating what happens naturally on woodland floors. At the surface you may see leaves, twigs, and small plants, but as one digs into the ground they would find dark crumbly decaying leaves right below, and even further down: a rich brown humus.Deciding when compost is “finished” is quite arbitrary. However it is commonly agreed upon that compost is finished when the original material is no longer recognizable and the more easily decomposable materials have completely turned to humus.

Why should we even bother to compost anyway?

In the United States, people waste 92 billion pounds of food annually, equal to 145 billion meals. They throw away over $473 billion worth of food annually. Shockingly, they waste 38% of all the food in America. Most waste is incinerated or disposed of in landfills which emit methane. In fact 25% of the United States’ methane emissions come from landfills. According to Thompson, roughly half of all household waste could be composted. Meanwhile us gardeners spend un-told sums of money buying various growing media, soil enhancers, and mulches some of which contribute to environmental degradation such as peat moss. The National Gardeners Association estimates that we spend $35 billion per year on supplies for our lawns and gardens.While soil amendments may still be necessary to optimize the yield of your garden (in some cases), instead of spending our money and contributing to harmful environmental practices, we can help to amend our soil naturally via composting.Before compost is even broken down, it can be useful as a mulching agent. Think of this as using wood chips or torn up cardboard boxes to suppress weeds in summer, retain soil moisture after a rain, or to protect the soil against erosion from the wind or excessive watering.

Compost Basics:

Broken down compost contributes to the organic matter and mineral content in the soil. The organic matter or humus from the compost is held in microscopic clumps along with minerals via hyphae or fungal strands. These clumps provide a home for bacteria. The hyphae and bacteria breakdown the organic matter providing simple carbohydrates and nitrogenous precursors that are used to build plant walls and carbohydrates. The most important minerals provided by compost are nitrogen (N), phosphorous (P), and potassium (K). NPK are like the big three for plants with other important minerals being calcium (Ca) and magnesium (Mg), among many others. Furthermore the organic matter, mineral, bacterial, and fungal content influence the soil structure subsequently affecting how well the soil holds water and the air content of the soil which are also quite important in the growth process of plants. Thus what many people simply call dirt is actually composed of an intricate microenvironment that is capable of providing the building blocks of our plants during their photosynthesis in addition to influencing water and air availability.Thompson goes on to write that a typical square yard of woodland may contain 30 million nematodes and 250 species of mites. There are several other microorganisms as well, each preferring different types of organic matter and thus living in a symbiotic relationship with the plants as their breakdown products provide the building blocks that plants need. Worms like compost and worms aerate soil and pass organic matter through their digestive system. Fungi and actinomycetes eat fibrous materials that are tougher for other species to eat.

Making Compost:

Compost needs water, air, warmth and an adequate carbon to nitrogen (C:N) ratio. Similar to humans, the microorganisms dining on the compost pile need carbohydrates such as bread, potatoes, fruit, and vegetable scraps. Keep in mind these scraps also provide cellulose that we cannot digest but microorganisms can. These are things like vegetables and fruit rinds/skins. In addition just like we need protein, the microorganisms also need nitrogen and phosphorous to make proteins. The carbohydrates are the main source of carbon. Similar to how humans eat more carbohydrates (source of carbon) than protein (nitrogen) the compost microorganisms need more carbon than nitrogen with the optimal ratio being 30:1. The microorganisms actually have a preferred ratio of about 5-10 but roughly 2/3 of the carbon they eat is given off as carbon dioxide (CO2).

Common compost additives and their C:N ratios

Poultry manure 6
Vegetable kitchen waste 15
Grass cuttings 20
Tree leaves 50
Straw/hay 80
Wood and paper 100-500

In order to get a ratio like 30:1 we have to mix some low nitrogen items (like woodchips or paper) with higher nitrogen materials (like grass cutting or vegetable waste). In addition (and potentially more importantly) the carbon rich materials tend to be fibrous and thus provide some structure to the compost to help aerate the pile.

A balanced diet for the pile generally consists of about three parts soft green nitrogenous material to one part woody or brown stuff. It’s important to keep the compost pile aerated so that aerobic metabolism continues to occur. If the pile is starved of air and becomes aerobic then it (1) takes longer to break down and (2) some of the anaerobic by products such as ammonia (urine smell) and hydrogen sulfide (rotten eggs smell) smell pretty awful. The only drawback to woody materials is that they take a longer time break down which is why shredded paper sources are often recommended instead.

Compost Ingredients:

Composting is similar to cooking: there are certain ingredients you’ll want to include while excluding others. As noted above we will want to roughly optimize the proportion of C:N but in regards to ingredients the general rules are:What to add to the pile: “green waste”

Coffee grounds (Most coffee shops like Starbucks give these away for free!)
Egg shells
Fruit & vegetable scraps
Straw
Vegetable stalks
Breads & starches
Tea bags
Hair/fur
Lawn clipping (nothing that’s been sprayed with various pesticides and fertilizers)

And to a lesser extent “brown waste” or “woody waste”

Shredded up cardboard (egg cartons and toilet paper rolls are easy to rip up into very small pieces)
Very small twigs
Leaves
Peanut and other nut shells
Corn stalks

What to avoid putting in the pile:

Fish & fish waste (can attract rats and other unwanted animals)
Meat & meat waste (can attract rats and other unwanted animals)
Animal waste (potential pathogenic bacteria)
Directly adding oil or fats
Inorganic materials including foil, glass, plastics and metals, and pressure-treated lumber.
Synthetic chemicals (could potentially make the pile toxic)
Diseased plants (organisms that cause disease can survive composting and spread to other beds in the garden!)
Very woody material (will dry out the material plus larger twigs, branches, and stalks have a low surface area to volume ratio meaning they will take a very, very long time to break down)
Laminated cardboard like juice boxes and milk cartons
Large quantities of newspaper
Glossy magazine paper

Weeds present a gray area when it comes to composting. Definitely avoid weeds that have gone to seed as the seeds may survive the composting process and end up wreaking havoc in the garden bed. However weeds may provide valuable organic matter. Roots of perennial weeds like dandelions and couch grass will likely not be phased by our small compost pile, so we have to make sure we destroy whatever weeds, whether they be annuals or perennials, before adding them to our compost pile. A simple solution may be to suffocate weeds in a hot trash bag for several months before adding them. Another solution would be drowning them in buckets of water however that may bring about the unintended consequence of attracting mosquitoes.

Other matters

A compost pile will always be hotter in the center – turning the pile regularly helps to aerate the pile and by getting the material that was on the periphery to the center it ensures the microbes living in the center of the pile are not hurting for food. Bacteria that prefer cooler temperatures will migrate to the periphery. A gardener’s compost pile is not as large nor as hot compared to a municipal compost pile, thus the bacteria in our pile will mostly be mesophiles or bacteria that live at everyday temperatures (<113oF). However if the pile does manage to get hotter center temperatures the bacteria inhabiting that area would be considered thermophiles or heat loving bacteria that thrive at temperatures up to 158oF. Even in this case the increased temperature would be short lived unless we continuously added new materials to pile in combination with strategic turning. Otherwise high temperature composting is short lived, lasting no more than three to five days. The reason for this is thermophiles eat very fast and thus use up all of the available degradable materials in short order thus they essentially put their population in a food shortage. When the thermophile population degrades much of the organic material at the center of the pile and starves off, the temperature of the pile gradually cools and the mesophiles return.Calcium is critical to the pile as well. As the microorganisms break down carbohydrates, they produce organic acids (think of how apples can be fermented to make apple cider vinegar; vinegar is an organic acid). In piles that have good aeration the acids are further broken via aerobic (air requiring) metabolism of some of the pile microbes. However when the pile is not well aerated and the acids are not broken down problems can ensue. Some of the microorgansms in the compost pile do not tolerate acidic conditions very well so the pH of the pile has to be buffered (balanced) by something that is basic. Guess what happens to be basic and thus counteract the acid: calcium. Acids have a low pH and bases have a high pH so bases and acids counteract each other in regard to pH. As a point of reference, water has a pH of 7 and is considered neutral as the acidity scale ranges from 1-14 . Most plants thrive in a slightly acidic to neutral pH (6-7). However a neutral to slightly basic pH (7-8.5) thus with calcium being basic It helps create the ideal situation for the microbes that breakdown the compost pile.

Compost materials high in calcium include:

Brassica leaves and stalks. The brassica family includes cabbage, broccoli, cauliflower, collard greens, and radish to name a few.
General kitchen vegetable waste
eaves of ash tree, cherry tree, elm tree, hawthorn tree, linden tree, maple tree, and rose bush

Compost materials low in calcium include:

bark
bracken
conifer needles
hay and straw
leaves of birch tree, beech tree, hornbeam tree, oak tree
moss
wood in general

In addition if the pH of the pile is not maintained naturally, the addition of ground limestone is an option but this is the equivalent to giving a medicine rather than treating the root cause which is likely poor aeration.