Saturday, May 23, 2009

Composting 102 - Heat

Alright, now for some application of the principles. First, where does one acquire such copious amounts of mature and immature material? There are three options: don't worry about it and build piles with what you've got, scavenge from your neighborhood or surrounding land, or plan to grow enough of what you need. Each option has its upside and downside.
Using what you have available is easiest, but does not always end in a balanced pile. Usually you will be heavier on the immature material, unless you buy a bale of straw, which leads to the second option.
Scavenging from the woods, fields, lawns and farm supply stores can also lead to an unbalanced pile, but that is less likely. The only three objections I can think of are that it might cost money (gasp!), the material may have qualities you don't want to introduce to your system (like pesticides), and you would technically be stealing fertility from another source. Granted, the local coffee shop may only have one other outlet for all those grounds (the trash) but you are still importing it to your system. Obviously this last objection is more philosophy than practicality. The farmer we learned from in our first internship made a deal with the township that, when they went around in the fall collecting leaves from curbs, they would dump them on his farm. He would then mix these massive piles with some nitrogenous material (horse manure) and let it compost. Often, when spreading this compost, we would find little plastic toys that got raked up with the leaves. It kept us amused... And sometimes made us wonder what else the leaves carried with them. But this farmer had found an incredible amount of mature material, delivered right to his farm, for free. And you can't really argue about the practicality of that. He was farming on a market scale, though, where most of the farm's nutrients are being exported as food. You have to balance things somehow.
Ok, so addressing the first point of the second paragraph: a pile that is unbalanced, favoring the immature. For the record, "unbalanced" is completely relative here, because things will compost no matter what. But when we are trying to get the best possible result, we should keep an eye on what goes in. Allow me to dig briefly into the biology of the compost pile: Once you have built it, the microorganisms in the environment go to work, assuming there is enough moisture. They consume, among other items, nitrogen, carbon, and oxygen. Unless the pile is too wet, in which case the pile turns anaerobic, meaning the microorganisms doing the work operate without oxygen. This will smell bad, your neighbors will resent you, and the finished product will not be so pleasant. I speak from recent experience.
But assuming it is aerobic, meaning oxygen is involved, your compost will smell nice or not at all. As the microorganisms go to work their metabolisms rise and with it their temperature, so much so that the temperature of the whole pile rises. Eventually it will get too hot for the active population of microbes, at which point other populations will become active. This continues until the material available to the microbes is consumed by them.
How hot does it get? That depends on the food you are presenting to the microbes. Two things will affect temperature most: the amount of immature material and the amount of oxygen. If you build a pile only out of grass clippings your pile may get quite hot, upwards of 160° F. If you forget to apply water to a pile of grass clippings and chicken manure (which is HIGH in available nitrogen) it can conceivably get hot enough to combust. Don't try this at home, kids. When a pile gets turned, oxygen is brought into the system in new quantities, which will cause the microbes to become active again, heating up the pile.
To a degree (ha!), heat is beneficial. It means things are working, and at a faster pace than if the temperature were lower. But at a certain level heat becomes unproductive, causing some of the nutrients to which you'd like to hold on turn into gases and exit the pile. Additionally, high heat will kill populations of microbes. Which is actually the point in some composting schools of thought. If you can get your compost pile to reach 160° F or more it will kill most of the disease-causing microbes and many of the seeds that made it into the pile. The downside is that, along with most of the pathogens, all of the beneficial microbes will be killed off. And what holds disease in check? Beneficial microbes. So all you have left in your pile is the most tenacious population. In Grow Biointensive we aim not to eradicate negative populations, but keep them balanced by the beneficial populations.
What, then, is the ideal temperature? We aim for no higher than 140° F. Oops! How did that picture get there? We have compost thermometers with 18" probes to get to the middle - a very handy educational tool. This pile got a little too warm by our standards. The photo below showcases a more reasonable temperature.
These are both examples of classic late-spring piles. Our mature materials from the year before are almost used up, but we still have immature cover crops to pull out. These immature crops are becoming more and more mature in quality, but still have that slightly higher nitrogen content. So the piles, like the days, tend to be warmer. In the fall we have lots and lots of mature material but not much immature. They tend to be cooler. The air temperature plays a role, too. If it is freezing outside you probably won't have a 140° F pile.
As to the turning, it is a trade-off. Some nutrients will be lost in the turning, it's true, but if you don't turn it at least once the materials on the edges of the pile will not break down. We generally compromise by turning each pile once. (For the uninitiated, turning involves taking the pile, piece by piece, and rebuilding it in a neighboring location. Not flipping it over all at once.) There are contraptions called "Compost Tumblers", which are drums that pivot on a horizontal axis. They allow you to put your materials in and turn them as often as you like. Once again, more oxygen, higher heat, and cured compost faster. With greater nutrient loss.
What is turning into a series will probably wrap up with the third post, which will cover manure, undesirable material, compost quantities, and miscellaneous other. Enjoy!

Monday, May 18, 2009

Why We Are Tired Tonight

Whew! This is what summer is all about... All seven and a half of us just left the garden at 9:00 pm, having gone on a wild planting spree. Main season things, you know.
So far we've gotten a start with some sweet corn, tomatoes, quinoa, sunflowers, and onions in their beds. Tomorrow will bring amaranth, with flour corn, millet, sorghum, peppers, eggplant, cukes, zukes, and many others to follow.
There's no going back now!

Sunday, May 17, 2009

Composting 101

Here I sit, in the shade, sipping cold kombucha in the midst of our first 100° F days of the year. What topic could be hotter than compost? Or more appropriate, given that it is Spring and we have an abundance of weeds, cover crops (which we refer to instead as "compost crops"), and all the dry, stalk-y, crunchy mature material we saved from last year.
Michele, of the Rabbit Wrangler Ranch in Idaho, posted some questions after reading my admittedly vague reference to our composting in the Happy Spring Equinox post. Hopefully this will answer your questions and bring up a lot more.
I often feel like most of my experientially-oriented posts should start with a disclaimer, so here's this one: there are many ways to compost, many books written on the topic, and many, many products sold to help you compost. This is how we do it here, and how it is taught in Grow Biointensive agriculture through Ecology Action's courses.
The recipe is fairly simple: 4 parts mature material, 4 parts immature material, one part soil. Add water. Sounds easy, right? It is. And the details aren't even very devilish.
Mature material, popularly referred to as "dry matter", consists technically of any plant matter that has achieved full maturity. The easiest example is straw, which can come from rice, wheat, rye, barley, oats, and so forth. Also included are corn stalks, quinoa stalks, sunflower stalks, amaranth stalks... You get the picture. Essentially anything that is tough and crunchy. Tree leaves that fall of their own accord count. Burnt bacon doesn't.
Immature material, popularly referred to as "green matter", is basically anything that has not gone to maturity. Slug-eaten lettuce, grass clippings, most kitchen waste, weeds (which you hopefully got before they went to seed), and anything else you pulled out before it completed its life cycle.
The reason for the revised terminology is that the common terms are deceptive. Grass clippings that have been sitting on the lawn for a week can certainly be dry and brown. But that does not change their composition, except that there is less water in them. And it's all about the composition.
I will oversimplify to prove my point: for our composting purposes, anything you put in your pile is made up of carbon and nitrogen in varying ratios, and the carbon involved varies in its density. The mature material we use is relatively higher in carbon than the immature, and the carbon is denser. Because of that fact the organic matter from composted mature material will last much longer in the soil, which is what we want. But if you build a pile only of mature material it will take years to break down completely.
The microbes that will decompose your pile want appreciable amounts of both carbon and nitrogen, which is where the immature material comes in. Though its carbon is less helpful to us in the long run, immature material is relatively higher than mature material in nitrogen, and its presence in the pile will help the microbes do their job and give you lots of nice, long lasting compost (human-encouraged organic matter), which in turn makes your soil system healthier which makes your plants more productive and pleasing to the eye, and eventually culminates in world peace.
Soil is the last ingredient, and we add it in small quantities for a couple of reasons. It's true that adding soil inoculates the pile with helpful microbes (which would have happened eventually anyway), but more importantly it helps the pile maintain moisture and moderate its temperature. This may be less necessary in a cooler, moister climate than ours, but is vital here.
Now you know the ingredients, so here's how it goes together: Choose a spot to build your pile, preferably in direct contact with soil, and possibly on a garden bed you can spare. The liquid that leaches out will do great things for the soil underneath, and direct contact will also aid microbes coming and going through your pile. It should be a minimum of 3x3', which will help maintain the core temperature and moisture of your pile. It can be bigger if you like, but not smaller.
Stick a fork in the soil to loosen it where the pile will go, then lay down a few inches of rough mature material. This is a different category of mature, things that won't break down easily. Like tree branches. The point is to allow air to enter the pile and excess moisture to leave. It also creates a definable bottom to the pile.
Now you start building, adding a layer of mature, a layer of immature, and a layer of soil. We use 5 gallon buckets (not sustainable, no, but plentiful, free in any quantity, and standard in size for measuring). One layer for us is two buckets of mature, two buckets of immature, one-half bucket of soil.
Oh- and we build them as square as possible. This makes the most efficient use of space and materials. Plus they are aesthetically pleasing...
At this point, having not answered more than one of Michele's questions, I am going to end this post. The next will cover a little bit of the what's, why's, do's and don'ts of the process, hopefully answering some of the questions that this post generated.

Thursday, May 14, 2009

Interview with a Pair of Fanatics

Our friend Nikki, who was an intern at the Ecology Action Research Mini-Farm for a few months this past winter, came down to visit last week. Nikki is a writer both of journalism and fiction, and is also a health food nut. (Those of us who claim the term wear it with pride). Her passions also tend toward life-long learning and the sustainable lifestyle.
While the majority of her visit was spent with her sister, who is currently a six-month intern at the EA site, Margo and I did get a chance to have them both down at the Golden Rule for dinner and conversation. Nikki came prepared with her notebook and a desire to interview us about progress on our own path of self-sufficiency and healthy lifestyle.
Her finished product gives us a chance to step back and see that we have made some incredible steps. The fact that we play in the dirt everyday is the only thing that keeps us humble :)
Anyway, we recommend her blog, Generation V, and the interview in particular (for when the post has moved off the main page to make way for other excellent and more recent posts).
We are grateful that Nikki is friends with us even though we aren't vegans :)
And here is the one photo of four we gave her that she didn't decide to put in. I think it is self-explanatory.

Saturday, May 9, 2009

Integrated Pest Management, Golden Rule Style

Our Fava Beans aren't looking so hot right now. They are suffering, as they always do this time of year, from one of the biblical plagues so hideous it could only be referred to euphemistically as "locusts". Yes, I'm talking about Aphids.
Ours are black, and a little bit of research has me guessing that they are Aphis fabae, the Black Bean Aphid. They are the scourge of our Favas, and probably indicate something of which we should be aware (we are generally of the belief that most plants in any given crop will have pests or disease, but only the weaker specimens will succumb to the attack).
At any rate, we worry some about our beloved Fava Beans, high biomass producers that they are, and heralds of the coming of the Fava Bean Burger mentioned in an older post. Mostly, though, we worry about what other people will think when they visit the garden. So we kind of rush them past the Fava beds.
Until recently, of course, when we began to see the textbook example of what we preach in terms of pest management: Lay off the poisons, focus on a healthy system, then let natural predators step in. Most notably we have the Ladybug, which is our garden hero due to its status as a general predator. Once it has finished with the aphids, it will move on to other pests. Or, more likely, when it has eventually reproduced to levels too large to be sustained on the aphids the excess will migrate to the rest of the garden. So when the plants die (of natural deaths) in June or early July, we will have a ridiculous number of ladybugs spreading out for new grounds. A side-note here; Ladybug beetles and larvae both do plenty of eating, up to 50 aphids a day. And Recently a Dutch group called the Foundation Against Senseless Violence chose the Ladybug as its logo. Cute for us humans, ironic on an insect level...
Here we have an unidentified wasp species, which began arriving in droves a week or so ago. They hang out over the Fava Bean beds in the hundreds, maybe thousands, and create roving clouds in the rest of the garden. It isn't their eating habits that please us as much as their egg-laying habits. You can't say that for many things besides chickens, can you? These wasps, just a half-inch long or so, inject an egg into each aphid they encounter. The egg hatches, parasitizes the aphid, and then, when it has eaten all there is, leaves the aphid an empty shell (see left).
Here is another strange predator, which those more skilled or experienced might be able to identify. It is enough for me to know that, with a shape like that, it is not eating Fava Bean plants.
There we have it. If we had gotten wigged out by all those aphids and sprayed, dusted or otherwise applied poisons, the aphid population would surely have been affected. But so would the populations of all the predators attracted to the aphids. It is a basic law of predation that 1) there are fewer predators than prey and 2) the reproductive cycle takes longer for predators than prey. So when it comes to bouncing back from devastation, the prey will excel. Predator populations will come back much more slowly, leaving room for a great infestation before they catch up.
So here's to our ladybugs! May they always get their way in our garden.