Compost: It does an urban farm good

Urban farming is a good way to care for the land, take part in the production of the food we eat, and match human ingenuity with nature’s accumulated wisdom in a system that benefits both parties. Unlike much of human industry, which conforms to the model of (raw materials)-(labor)-(product)-(end use)-(waste), natural processes are all part of an indefinitely-sustainable, cyclic system. As you can probably guess, a major component of this system is the mechanism where the “waste products” are turned back into “raw materials” – a process called decomposition, which is driven by erosion, microorganisms, and other slow but effective actions taking place on and in our planet. And, like in so many other areas of human-environmental relations, the careful injection of a little ecologically-inspired human manipulation into an otherwise natural process can actually make it work better, to both our benefit and that of the natural world. In the case of decomposition, this is an activity that almost all of us can do, and produces the most useful product for the least amount of effort of anything you can do as an urban farmer. Let’s talk about composting!

WHAT IS COMPOST?

For those of you that don’t know, “compost” is a loosely-defined term for any organic matter – from manure, to leaves, to grass clippings, to food scraps – which has decomposed to the point of “biological stability”, where it will not decompose further. In a natural, geological timescale, this decomposition can take decades or centuries, but is a vital linkage between the waste and death that are unavoidable, necessary occurrences in the Earth’s biosphere, and the formation of new life.

It is the mechanism by which the Earth recycles its unneeded products back into the non-biotic “spheres” (into water, air, and most importantly, soil), which in turn actually increase the Earth’s ability to make new life!

But when an urban farmer makes a compost pile, a very small amount of effort at the right times makes the slow, natural process of decomposition happen in less than a year, and in as little as a few weeks.

HOW AND WHAT TO COMPOST

1) Throw all of your organic matter into a pile on the ground.

2) Turn it with a pitch fork or shovel (or let your chickens do it) for five minutes every few weeks. 3) Repeat.

That’s it.

You may think I’m joking, but I’m really not. In the most minimalist way, organic matter that’s concentrated into a pile and aerated (turned, to make sure there is fresh air dispersed throughout) will become rich, usable, biologically-stable compost in between a few weeks and a year, depending on ingredients.

But with a little more conscious effort, you can make the process happen faster, and produce more, better compost. First of all, I want to stress that aeration is key. Decomposition can happen either as an aerobic process – where the chemical reactions, and the bacteria that are involved, thrive in an oxygen-rich environment – or an anaerobic process – where there is little-tono oxygen, and the reactions and microbes are different as a result. Anaerobic decomposition produces more of a sludge end-product, in addition to copious amounts of methane – which itself is useful as a fuel source, but nonetheless

explains the smell of a landfill. But unless you’re planning on compacting and encasing your food scraps in concrete, your compost is already an aerobic decomposition process. By turning it regularly, and therefore injecting air throughout, you make sure those aerobic microbes thrive, and those oxygen-based chemical reactions can happen uninhibited. I can attest to this from personal experience – for years, my compost took a long time to break down and did not do so satisfactorily; I started turning it more frequently this year, and the level of decomposition that used to take months now takes a week or two.

The next consideration is the types of materials you compost. As I said: if you throw any organic matter into a pile and turn it occasionally, it will decompose. But by maintaining a proper carbon-nitrogen ratio in the pile, you can speed up the process and make better, more fertile compost. I won’t go into too much detail here, but the “brown”, carbon-rich materials include fallen leaves, twigs/branches, paper products, and other dry, often brown-colored plant material; “green”, nitrogen-rich materials include food waste, recently-living (green-colored) plants, grass clippings, and manure. To make the best, fastest compost, you should aim for about three parts brown materials to one part green materials, by volume; this can be as simple as throwing on a copious amount of saved fall leaves each time you bring out your food waste, or adding a handful of pulled weeds (I’m sure we all have some to spare) together with the branches you’ve picked up in your yard. You’ll also want to break compost materials down into the smallest pieces possible, to quicken the process.

Complete lists are available in many places on the internet and in the library, so I’ll just give a basic idea here: any material that came directly from an animal, plant, or microorganism, or which could be consumed by one, is fair game in composting. But if you’re like me, you want to use all waste for its highest value purpose, which is oftentimes not compost. Answer the following questions in order, to determine what to do with a particular item of organic waste:

1) Is it still edible for humans? If so, find a way to eat it. This could be candied citrus peels, vegetable-scrap-soup, or bread pudding (not that I would otherwise advocate eating bread or sugar).

2) If not, is it still edible for animals? Bearing in mind the toxicity of some things (i.e. chocolate for dogs, avocados and citrus for chickens), you can feed many food wastes to animals. Consult a trusted source, but I can tell you that my chickens are like garbage disposals, turning spoiled milk, garden weeds, and pepper seeds directly into eggs.

3) If not, is it otherwise usable by humans, like in the garden? Rather than composting big branches, they may be usable as stakes in your garden; shredded leaves and grass clippings also make nice mulches. Crushed egg shells, coffee grounds, and improperly dried hot peppers can all be used in specific ways in the garden, that maximize their value above and beyond composting.

4) If not, is it otherwise usable by animals? I often grow small amounts of grains; rather than immediately composting the stalks, I use them as nesting material for my chickens first; leaves are similarly used to line the bottom of the coop.

5) If not, can you use it for energy? This is heavily dependent on what systems you may have set up, but is essentially making use of the energy stored in organic material that would otherwise be lost as heat in composting. This could range from burning wood (at the simplest) to using an anaerobic methane digester to turn waste into natural gas (at probably the most complex) and everything in between, most of which produce an end-product (ashes, sludge, etc) that is then compostable.

6) If not, compost it! It may not seem like it, but since the bulk of your urban farm’s organic wastes are leaves and grass clippings, and since there are limited 1-5 uses for these beyond garden mulch (especially if you don’t have chickens), you’ll still have plenty of composting materials.

My Uncle Lambri is my de facto mentor and co-conspirator when it comes to all things compost. He meticulously manages the fallen leaves, grass clippings, food waste, rabbit manure, and garden waste in and around his home in order to produce perfect, valuable compost, which he uses to build up the soil in his yard and garden. His primary motivation for such enthusiastic composting is simple economics – rather spend the time collecting and bagging all of that organic material to be hauled to the state landfill (or town composting facility), he spends less time and effort to compost most of it – and produces rich topsoil, which he then doesn’t have to buy. He has turned a waste stream into a source of natural resources, looping the standard, linear model of (fertilizer/loam)-(lawn/ornamental plants)-(yard waste)-(landfill) unfortunately employed by most home-owners, into a regenerative cycle.

WHY YOU SHOULD COMPOST

If I haven’t already convinced you that you should drop this newspaper (or turn off the monitor) and find a suitable location in your yard for your new compost pile, then prepare for that to change. Compost completes the nutrient cycle in every natural environment, and therefore closes the production loop on an urban farm, contributing to resilience and self-sufficiency.

It turns nutrient- and energy-rich, but otherwise unusable organic wastes into an ultra-fertile component of topsoil (called “humus”), so you gain space in your garbage can (side note: since we started composting, our garbage can is half the volume it was before) and eliminate the need to buy soil and amendments, saving you money.

By adding compost to your soil, you increase its biological activity, and (curiously) both its water storage capacity and drainage capability; it aerates the soil, acts like a potent probiotic, complete with earthworms and other beneficial insects and microbes, and boosts the soil’s mineral and organic matter content, and therefore generally its fertility.

The making and using of compost saves money, increases food yields, and is beneficial to the natural environment. And you can reap all of this benefit with as little as a small container in your kitchen to collect food waste, and 10 minutes of effort per week. Now go start that compost pile!

Alex Kithes is an urban farmer and a lifelong resident of Woonsocket. He graduated from BU, with a bachelors in electrical engineering, and from Brown, with a masters in chemical, biochemical, and environmental engineering. Email him at agkithes@gmail. com or visit his blog at TheOpinionatedFarmer.wordpress.com. His column runs every other Sunday.