DIY - Fun with Microorganisms

by Clifford Johnson     Department: Earth

There's a lot of science to be found all around us, without the need for expensive equipment to uncover much of it. Two favourite places of mine for this are the kitchen and the garden, and in this and the next post I'll talk a bit more about the latter. The topic is not plants per se, as it was last time, but an important link in the chain of which plants are part. I'm talking about compost. The production of a rich soil in which plants can grow healthily is carried out by a wide variety of microorganisms that break down organic matter and recycle it into a useful form. Without them, and without this process (and ones like it) we'd basically have no life on earth, since the cycle that includes plants converting sunlight into a digestible form for animal life to thrive upon (yes, that's basically what plants are up to, ultimately) would be broken if those plants could not be broken down and reintroduced into the ground to make nutrient-rich soil for new plants. Human beings, using chemistry, have learned a lot about how to supplant some of this process, getting energy from fossil fuels (yes, I know, also from the sun, but long ago) and making various fertilizers to support industrial-scale agriculture we relay a great deal on, but it is an incomplete supplanting, and far from satisfactory - and it has arguably produced a host of problems (and also food that is simply not as nutritious as it is when produced in a balanced microorganism enriched soil).

The great thing about this is that it is simple, and you can do a little preparation to get it working for you. You don't have to have a large garden, or a garden at all. You can produce compost for your house plants or window boxes or other potted items indoors or on the patio.

What are the raw materials? A lot of household kitchen waste is a major component. This is the other bonus - you'll find that you'll be throwing away a lot less stuff into the trash if you take the time to throw organic matter into a separate container to be used in your compost project.

So what do you do? You basically mix it all together and leave it, maybe mixing it up every now and again every few weeks. The little critters will do the rest for you. So it is DIY minimal, again. The kind of container you use is really up to you, and there are several on the market. I think that its fun to just build one yourself, if you have the space for it, and I describe a project of my own on this below.

I did a long post on how I prepared my own compost starter pile, back in the Fall of last year. I won't simply reproduce it fully here, but instead recommend that you go over and have a look at it in full form on Asymptotia. My compost pile feeds on leaves and kitchen waste. I cook a lot, and so I produce a great deal of vegetable off-cuts, which are perfect (along with egg-shells, peels of fruit, spoiled fruit, and so forth) for variety. If you don't have a garden that produces leaves (or, in some cases, but not mine, lawn clippings), I'm betting that (if you cook) you sometimes have lots of leafy material from your cooking (old salad cast offs, keep those tops on the carrots from the grocery store or market and bring them home for your compost, and so forth).

Anyway, here's more on my thoughts, from that post, on compost's use and benefits to the gardener:

Microbiology? Well, the object of the exercise is to let nature turn any organic material that you have into compost - full of nutrients for growing new things. Compost is also good for moisture control, good drainage, and a host of other things that are beneficial to plants in the garden. How does nature do this? Bacteria, mostly. But for the bacteria and other microorganisms to do their job (digesting the material), one needs to give them good conditions to live in. Conditions involve the right amount of moisture, air, and food, and the point of my project was first to prepare containment for the compost manufacturing process, and then to prepare a good combination of raw materials, place them properly, and then leave the little organisms to their own devices to do their thing. Here's a good webpage at Cornell about the various stages of composting, the temperatures involved, and the various organisms (bacteria of various sorts, actinomycetes (a kind of filamented bacterium), fungi (various molds and yeasts), protozoa) that come into play at the various stages.

I had a fun time building some compost containers out of chicken wire (basically cylinders) lined with black garbage bags, which I describe in detail.

The next really interesting step is the mixing of the various materials I had to form a nice tasty starting point for our little friends to begin the conversion/composting process:

I put aside some clippings from some hedge work I was doing elsewhere in the garden. Today I took them out and began to prepare them. Basically, one wants a component of green matter in the mix, and so this was what I had here. A week away was supposed to have wilted everything and made it easy to get off the branches, but I'd left them in the bag, and forgot to put them in the sun for the week, so they were as freshly cut. Well, I bent my back into it, and put together a nice pile of small green bits - simply using my gloved hands to strip leaves off the branches. I used a pair of sharp clippers to help cut up some branch tops as well, so there's leaves and soft short twiggy bits. Then I opened up the bags of dry brown matter that I'd gathered from various points in the garden for the last couple of weeks.

The significance of different coloured leaves comes next. Basically, its all about carbon versus nitrogen, the two chief chemical currencies in the whole life cycle:

A bit of mixing followed next. The plan is to get a good proportion of green to brown, along with some moisture (but not too much), and maybe a little bit of a kick start. I read a nice description of the mixing process, suggested containment, and some background material of the relative merits of greens (lots of extra nitrogen) and browns (lots of extra carbon) on this website, and followed their suggested layering method for helping getting a nice even mix, since it seemed sensible. I had some kitchen waste (vegetable skins and so forth) which went into the mix too. I also sprinkled in some handfuls of organic compost (E. B. Stone's) that I had lying around, along with a few handfuls of top soil I bought a while back - the topsoil smelled a lot of manure, which is a good sign. Both of these latter should be rich in the right kind of bacteria, and so popping some in will help seed the whole mix nicely and help the processing begin.

Finally, after a discussion of the moisture that should be added (why type, and  not too much, not too little - it is important) I filled the containers, located them a quiet corner of the garden, and...

I covered them with squares of chicken wire (against critters) and left them for the night. If everything went well, in a couple of days the temperature at the core of the heap ought to be rather high indeed. The process will have begun.

We shall see.

I will report on their progress in the next post.

-cvj

Tags: biology, compost, gardening

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