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Composting/Compost pit


QUESTION: I live in Norther Alberta and would like to use a compost pit with the sole purpose of reducing the amount of garbage I send to the dump. I have an average size yard and there are 2 people living in my home. I want to put kitchen waste, grass clippings, and garden waste in the compost bin. I was thinking of digging a hole and putting a 24" x 30" patio stone on the base with gravel underneath for good drainage. I will build walls with cinder blocks on their side to allow worms access to the composting material. The top layer I want to use the firepit bricks that form a circle and then I have a steel lid that I will put on top to keep it enclosed. I want to have it sealed so that there are no smells or problem with pests.

1. Would building it as big as a 45 gallon barrel be big enough or should I dig it deeper in the ground?

2. With just adding material to the bin and not mixing it how long will it take to compost?

3. How much will the material reduce in volume?

4. Will worms get in and help the process?

Thank you

ANSWER: Hello Ian

Since I don't know the exact critera, or why you wish a pit, I will attempt to answer your concerns the best I can.

1, I have no idea, how often you mow your grass, or how much volume there will be associated with this. I have always found that it's trial and error.  Kitchen waste, such as greens, and peals won't take up much space. With all that in mind, 45 gallons seems a bit small.

2. How long will it take depends on what you put into it. Alternating browns, <carbon> with greens <nitrogen> will make it decompose quicker, and reduce odor. Heat, or sunlight, moisture, but not too much will speed the process. The smaller the material, the quicker it will decompose, but also create an oxygen starved enviroment. Mixing the matter, will speed the process, but if you choose not to, I would avoid grass clippings, or just sparingly, to avoid odors. Having it sealed, sort of defeats some of the purpose in this, so can I get you to cover it part of the time, and uncover it, say every other day?

3. When fully decpomposed the matter should be reduced 80-90% of it's original mass. When you can no loger distiguish what the matter was, that went into the pile, it's ready. Eventualy over time, say 5-7 years, after being fully decomposed, the Compost itself, decomposes to nothing.

4. Worms will FIND your pile, trust me on this one, if you wish to add some, feel free to do so.

If I have missed something here. please don't hesitate to follow up with another question, sometimes answers, just bring other questions.

The Very best of luck


---------- FOLLOW-UP ----------

QUESTION: My reason for doing anything like this is to reduce waste and keep biodegradable material out of the garbage dump. My city has a very poor garbage collection service so I want to let the worms do some of it for me. As far as keeping the lid open part time I have no problem doing so but because I live with neighbours on both sides so I have to be respectful and not have a smelly yard.

I'm guessing that I will have approx 3 bags of grass once a week. I have not yet  landscaped my yard but that is approx what it was in a previous home with a similar yard. How big would you recommend the pit to be if 45gal seems small? Keeping in mind the contents will likely reduce before more is added. Is the described construction of the pit a good ideea?

ANSWER: Hello again

3 bags of grass is a lot for 45 gallons. The way to keep the grass from that disgusting ammonia smell is to spread it out, and add carbon. Fall leaves are an excellent source of carbon, but the timing of fall leaves and grass clipping pose a challenge. The proper ratio, of Carbon to Nitrogen is 25-1, for ideal composting. Thats not to say if this is not met, you have failed, it just means this is ideal. Can you save any leaves from this fall? Put them in a bag, paper bag, and save them to add? Leaves will not smell if you have some out of the way place to store them. Use this as a base for starting, say 6". Then add 2" of grass clippings, and just enough garden soil to cover the clippings. then add just a small amount of water, easy on the water. then start over with the leaves and keep going till it's filled. You can substitute your greens for the clippings, this is nitrogen. This will help with the smell, as the carbon will hold that back.

As you may have figured out already, this 45 gallons will fill up quick. I myself,  take excess grass clippings and use it as a mulch in my Vegetable garden, spreading it out in a thin layer over the soil.

I would have 2 45 gallon areas working, if you have the space, one which you could call "in process or working" while the other could be the finished or "using".

Anything that is made out a paper is carbon, such as newspapers. Shredding them is a good source, till the Fall Leaves become available.

The very best of luck


---------- FOLLOW-UP ----------

QUESTION: Would building it extra large be a similar solution. I could dig it 5' deep and have the diameter of a round fire pit. If I cut grass one day and a week later cut again with it have reduced any great amount in that week?

I have heard this style of composter called a compost digester. It is my goal to reduce volume of garbage, not harvest compost.

Hello again

Yes if harvesting the matter for a constant supply of compost is not your objective, then yes, a larger pit is what you would need. I am trying to focus on your concern for odors, and any matter that your neighbors might have with this. To balance out the grass, you need to add carbon, and not layer the grass in the pit too thick. Adding a little ordinary soil, as you layer everything, will act as a spark for bacteria, moist with water, but not wet, which is hard to to in a pit, and of course your carbon at about a 4-1 ratio.

This should help you in your objective.



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