Tuesday, March 1, 2011
Gourmet Vegan Compost = The Recipe
The Vegan Part
I used to use horse manure as the primary nitrogen source in my compost. One day one of my students asked if it were possible to make vegan compost. After a minute of choking back a burst of laughter i said it probably could be done. What do horses eat? Oats, alfalfa, other types of hay... What they don't digest comes out as manure. Oats are seeds which are storehouses of nitrogen. Alfalfa is a legume so in symbiosis with rhizobium bacteria captures nitrogen from the air. I have seen analyses of alfalfa meal indicating it is about 6% nitrogen, 4% phosphorus and 2 % potassium. Yes I believed it would be possible to make vegan compost using the food horses eat! Not hay though because it could be contaminated with Grazon a powerful and dreadfully persistent herbicide used to kill broad leaf weeds in pastures.
The Gourmet Part
Funny Farm Truism #1 - Compost is only as good as the ingredients that go into it.
If you make compost from organic matter that grew in soil that is deficient in nutrients your compost will also be deficient in those same nutrients. Compost does all kinds of good things in the garden but correcting nutrient deficiencies is not one of them. Only soil testing and the addition of sources of needed nutrients as indicated by the soil test can do that. Compost does bolster the soil food web to increase nutrient availability, retain soil moisture, and improve soil structure.
We add ingredients to our compost piles to increase diversity of nutrients in the finished product. We use native granite sand, the parent material of our soils and kelp meal which contains over 70 different nutrients necessary for producing nutrient dense food (more about that in a future post). That is what makes our compost "gourmet" :)
Carbon Sources (brown stuff) - enough to make a 4'x4'x4' pile which is the minimum size needed to make a proper hot compost pile. Garden debris such as tomato vines, chopped okra, sunflower, pepper stalks, tree leaves, old straw (not hay).
Nitrogen Sources (green stuff) = 1 large (40lb) bag alfalfa meal, 1 large (40lb) bag whole oats. We get these from our local feed and seed store. A couple of days before i build the pile i pour the oast into a large galvanized tub and fill it with water to get the oats to begin sprouting so that they come alive. This allows the microorganisms to break them down.
Micronutrient Sources - 1- 5 lb. bag kelp meal and 25 lbs of local granite sand which we get from our nearby stone center.
Once we have all the ingredients assembled we build the pile by layering the ingredients like making lasagna. A layer of garden debris, some oats, some alfalfa, some sand, some kelp. Wet it thoroughly. Repeat until all the materials are used up. Shape the pile into a nicely formed mound.
I have done this many times and within 24 hours the pile will heat up to 140=150º. The temperature will slowly go down below 135º within a week at which time i turn the pile to re=aerate it and the temperature will go back up to 140=150º. In another week i turn it again. The goal is to get all of the parts of the pile into the middle of the pile so that they will be exposed to temperatures above 135º which kills most of the weed seeds and disease causing organisms.
After the 3rd turn, the pile should be turned about once a month until the process is complete which takes 4-6 months. We make a pile in the fall for spring use and a spring pile for fall use.
I rarely let a compost pile finish on its own. As i said in the previous post i use worm castings in our seed starter mix. After a new compost pile has worked for a couple of months i feed it to our worms who, in 60 days, turn it into the most beautiful, nutritious castings (worm poop) one can imagine. More about our vermiculture methods in the next post.