Trench Composting Disadvantages: Are They a Big Deal?

Trench composting disadvantages

If you’re looking for a set it and forget it composting method, trench composting could be for you. However, before you get started with this method, it’s a good idea to learn about trench composting disadvantages. After all, no method is perfect.

In case you need a refresher, trench composting involves burying organic matter such as leaves and food scraps in a trench in the ground. There’s no turning material or moving finished compost. Rather, you form the trench the same place you want the finished compost to go.

While this method requires few materials, low startup cash, and little supervision, it does have a number of disadvantages.

Short Answer: What are Trench Composting Disadvantages?

Disadvantages of trench composting

Trench composting has a number of drawbacks. The disadvantages involve both the quality of the finished product as well as the labor required to get started.

A major disadvantage of trench composting is that it’s a slow process. Since the starting material is buried and left undisturbed, the composting process is anaerobic. This lack of oxygen also leads to the possibility that harmful pathogens may exist in the finished compost.

Another main disadvantage is the labor in digging a trench. Depending on the amount of material you have to compost, this could be some serious digging. Plus, you have to have access to an area where you can dig a trench.

A final disadvantage is this method could attract pests if the trench isn’t deep enough.

While that’s the short answer about trench composting disadvantages, we’ll explain more about these cons below.

Trench Composting Isn’t the Quickest Method.

As I mentioned above, trench composting isn’t the fastest way to turn organic material into finished compost. To understand why, let’s review aerobic vs. anaerobic breakdown.

Aerobic composting is done by microorganisms that require oxygen to survive. When you turn a compost pile or rotate a compost tumbler, you inject oxygen into your composting materials. Since trench composting doesn’t involve any turning of materials, oxygen is not added throughout the process.

When aerobic microorganisms break down organic materials, they release heat and carbon dioxide. This heat speeds up the composting process and also kills weed seeds and pathogens.

Anaerobic composting is completed by microorganisms that do not require oxygen. As these microbes break down organic material, they release methane rather than carbon dioxide.

While carbon dioxide receives a lot of attention for its role in climate change, methane is actually a much more potent greenhouse gas. During the first twenty years after it’s release, methane is more than 80 times as potent as carbon dioxide! While a small backyard trench won’t release lots of methane, it’s still a point to consider.

Anaerobic composting and pathogens

Furthermore, anaerobic composting does not heat up materials enough to kill many weed seeds and pathogens. Pathogens can be killed through anaerobic composting, but the cause of death is unfavorable conditions aside from temperature. It’s important to note that it takes six to twelve months for most pathogens to die in these unfavorable anaerobic conditions.

Now that we’ve covered how oxygen plays a role in decomposition, let’s circle back to how this impacts how long composting takes. Aerobic composting can form finished compost in as little as six weeks, while anaerobic composting takes six months or more.

So, if you want to quickly form finished compost, trench composting might not be for you.

Get Out Your Shovel, and Get Ready to Dig a Trench.

As you might have guessed, trench composting requires some digging. Before we get into the details of digging, let’s remember that you need to have access to a place where you can dig a trench!

If you live in an apartment or urban area without a yard, you won’t be able to dig a trench. Even if you do have access to a yard, it might be covered with gardens that you don’t want to dig up. And, you’ll have to check for any underground utilities.

Also, remember that trench composting forms compost in the same area the finished compost will end up. While you don’t have to add compost to plants with trench composting, you do have to do some planning.  For example, if you want to plant a garden in May, you shouldn’t dig a trench in late April.

Trench composting

Now, back to the actual act of digging. While the length and width of the trench are flexible depending on how much material you want to compost, all trenches should be at least one foot deep.

For some people, digging a trench is a manageable task. However, it can be difficult if you’re dealing with heavy clay soil or physical ailments.

Does Trench Composting Attract Rats?

A commonly asked question regarding trench composting disadvantages is whether or not this method attracts pests such as rats. The answer is, it depends.

If you bury material deep enough, this method should not attract any pests. As long as the organic material is at least a foot underground, all types of pests should leave it undisturbed.

However, rats, raccoons, and insects may come to your trench if you dig a trench that is only six inches deep.

Final Thoughts

As with all composting methods, trench composting comes with disadvantages. So, before you select this method, think about whether or not these drawbacks will be a dealbreaker.

To review, trench composting is an anaerobic process. Therefore, it takes at least six months to complete, and the finished compost may include harmful pathogens and/or weed seeds. Two other drawbacks are that you have to dig a trench, and shallow trenches can attract pests.

Before you write off trench composting, learn a bit more about the advantages of this method to decide if it is right for you.

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