|Re: Compost||<– Date –> <– Thread –>|
|From: Douglas G. Larson (ddhleearthlink.net)|
|Date: Wed, 8 Oct 2014 11:09:56 -0700 (PDT)|
I would be happy to share experiences and photos. I was certified as a Soil Foodweb advisor in 2006 and we have been actively doing hot composting here at Songaia Cohousing for 4 years. Our hot composting site is a 5-bin system that one of our residents designed and built 4 years ago. The first bin is simply a collection bin for garden waste. It has wire fence sides to contain it and is open in the front. The 2nd bin is wood on 3 sides and open in the front. We use this as a prep bin, i.e. we use a power chipper to chip everything from the collection bin into this. Then we have 3 processing bins, each about 1.5 cubic yards. They are wooden sides each with a lid. The front of each are 2x4's stacked in a slotted grove so removal of the front is easy. The 2x4 fronts as well as the other 3 sides have spacers so air can get into the bin. If you read books on composting you will find that all of them state that the bin should be a minimum of 1 cubic yard, i.e. 3-ft x 3-ft x 3-ft. But when we built our bins I asked that they be 1.5 cubic yards. The larger volume makes it slightly easier to build heat but not so big that labor becomes unmanageable. So our bins are about 4-ft x 4-ft x 4-ft. As you are probably aware, there are 3 composting methods - Hot composting - also known as thermophilic composting where a pile is built and quickly comes to a high heat (around 120 to 150 degrees F). This requires frequent monitoring and turning. It is the most labor intensive of the three methods but can produce finished compost in about 2 months. Static composting - This is where you build a big pile and don't do much to it. You might turn it once or twice during its process but otherwise it requires little work. This method takes from 8 months to a year to produce finished compost. Worm composting - also known as vermicomposting. This is where worms do most of the work. This method works best on food waste and requires special worms and special bins designed for this purpose. If left unattended or filled incorrectly the whole batch of worms can die, leaving you with a mess to clean up. But if done correctly it will produce finished worm compost continuously. You simply remove the finished compost from the bottom and keep adding food waste and shredded paper to the top. Our hot compost bins are set in concrete footings that hold the wood frame but the bottom of each bin is simply open to the earth. While our bins do have lids, designed to prevent rats from entering we do have rats that dig under ground into the bins. The rats are a bit annoying but otherwise haven't been a huge problem. I have some comments on your requirements for your new bins - Rat proof - this will be a bit difficult to achieve but probably doable if you have concrete floors and bins designed to allow air in but not small animals. Odor free - The presence or absence of odor is due mostly to how you build and maintain your piles. Compost, even during the processing stages, while not odorless, doesn't stink. The stink is due to the pile becoming anaerobic, i.e. not enough oxygen in the pile. Under these conditions anaerobic bacteria and fungi are taking over and they produce exudates that produces the stink (e.g. alcohols and other nasty smelling substances). The substances that produce the stink are not only unpleasant but they are not good for your plants if the material is spread on the garden. Three things will promote anaerobic conditions 1) Too much high nitrogen content. All food waste and scraps are high nitrogen. Grass is another example of high nitrogen item. When your C-N ratio tips too far to the nitrogen side, this promotes anaerobic conditions. 2) Not enough air in the pile. This happens when the material is too finely chopped and so fits together very tightly leaving less room for air to enter. You do want to chip the yard waste and some of the food waste because it will break down faster. Five percent, by volume, of a newly built pile should contain sticks and twigs about the diameter of a pencil. This helps create air pockets in the pile. You can also insert 1 or more air pipes as you build the pile. 3) There is too much water in the pile which tends to prevent air from entering. All piles do require the presence of water but too much water isn't a good thing and promotes anaerobic conditions. In our piles we use a 4-inch diameter perforated plastic drain pipe that we insert in the middle of each new pile. The pile sticks up above the top of the pile and facilitates air circulation. It works quire well for us. In addition the walls of our bins have openings that allow air to enter. Our piles do sometimes become anaerobic and stinky when we have put in too much green material but we then turn more often which brings in more oxygen and reduces or eliminates the stink. Aesthetic - This is largely a personal preference but well built bins can be attractive. Efficient and effective for residents - This is a somewhat complex mix of bin design and maintenance practices. The larger your bins are the more labor will be required to turn and maintain them. The bins need to be situated with plenty of space to walk around and work when building the piles and when turning them. Here at Songaia we compost our kitchen scraps as well as our yard waste. Both are in abundance. For the food scraps we keep 4 plastic waste cans (33 gallon size) with lids outside of our dining room. We don't allow meat or dairy in our food waste but otherwise everything goes into these waste cans. The composters take these waste cans and cart them down to the compost bins when its time to compost. The yard waste is already there in our collection bins. We have a water faucet next to our compost bins for easy access to water. We have 3 compost thermometers that we insert into each bin. Its an easy way to monitor the temperature. These are available online at several places. But some of them are not very good thermometers. I have found that the Tel-Tru brand compost thermometer is excellent. The price depends on how long of a stem you get. We use 18-inch stems and Tel-Tru sells these for about $40. They have a longer stems as well as larger dials that sell for more. http://www.teltru.com The temperature in a hot compost pile should reach 120 to 150 degrees F and stay there for at least 5 consecutive days. A pile hotter than 155 should be turned immediately so a thermometer helps with that decision. We have a chipper we use to chip everything, yard waste and food waste alike. It makes building the piles easier and more manageable. These machines are expensive (starting around $400 and going up to over $1200) but they are indispensible if you are composting a moderate to high volume of material. They are also very noisy. We wear hearing protection every time we use them. The Elvex company sells very good ear protection at very good prices. http://www.elvex.com/ I will take some photos and send them to you later. Douglas Larson, Songaia Cohousing - Bothell, Washington
- Re: compost, (continued)
- Home Available in Manzanita Village drmaryann49, October 10 2014
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