Composting Pet Waste
October 2, 2021
My zip code is 91219. We are in San Diego, CA. We are situated on the side of a hill. The ground is rocky and dry and the weather oscillates between hot and cool. I want to compost my pet waste. I have been looking and reading about several in-ground set ups, but I am concerned that I won’t be able to keep the moisture at 50%. I don’t have a lot of shade options around our yard either. The final concern is simply digging a hole deep enough. There are many drainage and irrigation lines running through the ground.
My questions are- 1) Do you think the in-ground composting is an option with some modifications? 2) Is there an above ground composting method that would be better?
I would appreciate any input you may have!
Answer by JZ: Here are my thoughts: Pet waste may be composted separately, then ideally the end product could be used around ornamental (non edible) plants. So then you’d not have to be concerned about pet pathogen transfer issues.
Actually a container in the soil with a lid, would be a fine moisture preserving method. If the container top receives abundant sunshine, then you might cover the top with a few layers of cardboard or a few layers of shade fabric, then hold in place with a rock. Use a piece of plastic as a drape to cover the top of the inside the bin contents, this will decrease evaporative loss. Then put the lid on the container.
A suitable container, of any size with a lid, is described on our website. See Homemade Bins under Composting Info (Bucket in a Hole).
An above ground bin placed in the shade or covered with a few layers of shade fabric would work for you too. Once again the end product of pet manure compost should be safely used only on ornamental plants. A suitable bin of any size may be made from a trash can. (Again, see Homemade Bins.)
Follow the directions on pages 5-7 of this brochure: docs.nmcomposters.org/composting-in-the-desert-2018.pdf
So pick a container, get started, then you will learn what works for you. Let us know if you have questions.
Answer by MR: I’m replying also because several years ago I was confronted with a similar situation to yours. My soils aren’t shallow, nor are we on a hillside, but I wanted to eliminate smells because we have a working farm and none of our neighbors farm any more. Instead they have planted their agricultural fields to lawn, gotten rid of their animals, and suddenly they wanted everyone around them to behave like suburbanites also. I wanted some way to quickly decompose our dog and cat waste with no smells and no risk of pathogens infiltrating our high water table. So I used a modified bokashi bucket system, similar to what JZ is suggesting. I simply cut out the bottom of a round 5-gallon bucket, sunk it in the ground about 6″ deep near some young seedling trees I was planting to establish a hedgerow (you could fertilize already existing shrubs, as JZ has suggested), and placed large logs around it as a disguise. I put a large stone on top, easily removed when I added my weekly deposit of poop, and sprinkled bokashi bran on top. Inside I had fashioned a plate with a brick to keep the oxygen out. There was no smell, almost no yuck factor (as our link amusingly refers to it), and to my surprise, the waste largely turned to liquid fertilizer and sank into the ground. The surrounding trees and shrubs have grown amazingly quickly, despite our ongoing near-record heat and drought, and despite the fact that I don’t irrigate the hedgerow at all. It exists entirely on rainfall and groundwater.
The fact that bokashi will speed up the decomposition process means you don’t have to leave the bucket in place for extended periods of time, nor do you have to dig an extremely deep hole. Just pull the bucket out when it has reached a comfortable state of fullness and the contents are well-fermented (usually 2-3 weeks after the last deposit). Then cover the older waste, place the bucket in a new hole, and proceed as before. You don’t need to add any liquid, and the bokashi bran is a very inexpensive investment. And you can make your own to save even more money.