How Long Does Newspaper Take To Decompose Under Mulch?

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Willie writes on small engine repair, landscaping, and lawn care. He owned a professional lawn care business in Alabama for almost 10 years.

How Newspapers Decompose Under Mulch

Newspapers are an everyday item that people use when they are gardening and farming. It’s a relatively harmless material to decompose in the ground, and it can do so at a rate that’s not extremely fast nor too slow.

One benefit of the slower decomposition is that it can help protect against weeds. So why do newspapers decompose slowly under mulch?

Even though newspapers don’t decompose independently, they quickly start to deteriorate when you put them in the ground. This decomposition rate is because of the presence of water and acids in the soil.

This chemical reaction helps break the newspaper down. In turn, it starts a process called acid hydrolysis, leading to the newspaper decomposing (source).

So even though your newspaper might retain its look and feel for decades when stored in a dry place in your house, it can disappear in weeks when you bury it under the dirt and mulch. Because mulch can increase the acidity in your soil, this speeds up the process of newspaper decomposing.

Speeding Up Newspaper Decomposition Under Mulch

So let’s say you actually want the newspaper to decompose quicker.

You can do several things if you want to speed up the process of newspaper decomposition under your mulch. Let’s take a look at a few things that could make the process of decay quicker for you in your garden:

Choose a time of year when the weather is warm. “Heat is the enemy of newsprint. It speeds chemical reaction” (source). If your goal is to decompose, then heat is your best friend. Pick a summer month where you know the temperatures will be hotter, and put your newspaper under your mulch as heat will accelerate the decomposition process considerably.
Shred the newspaper before putting it under your mulch. Shredding your newspaper is a faster way to make it decompose below your mulch in your garden. It’s not nearly as detrimental to the environment as other materials. Rest assured that you’re not causing significant harm by the decomposing newspaper under your mulch. (see our article How To Shred Newspaper For Compost, Mulch, And Weed Barriers).
Use a mulch with higher acid content. Another way to speed up the decomposition process, use a mulch with higher acid content. Some of the best mulches for increasing decomposition are pine and sawdust. These create a chemical reaction where the moisture underneath the soil heats up and increases decomposition (source).

How Can You Slow Down Decomposition of Newspaper Under Mulch?

Most people who put newspapers under their mulch aren’t trying to make it decompose quickly. They bury it underneath to prevent pesky weeds from growing. So how can you make your newspaper decompose slower?

You can slow down the decomposition of newspapers under mulch by using thicker layers, choosing a less acidic mulch, or putting the newspaper in the ground when you are experiencing colder weather conditions. Cold slows down the decomposition rate, making the newspaper last longer.

As I discussed earlier, shredded newspaper decomposes more quickly, so adding a thicker layer of unshredded paper can slow down the process. Here are the two other ways that you can slow down the decomposition rate of newspapers:

Use a less acidic mulch. Because acidic soil can make things decompose faster, it would be a good idea to use a more neutral mulch if you want to avoid the fast decomposition of a newspaper. Typically you would like to use a hardwood mulch for your garden if you wish for your newspaper to decompose slower.
You could wait until colder temperatures to put it underneath your mulch. While decomposition never stops unless the ground is completely frozen. But decomposition does slow down as temperatures dip, which would cause your newspapers to decompose slower (source).

Conclusion

Decomposing newspapers is an increasingly popular activity that is less harmful to the environment than you think. There are various reasons you may want to decompose newspapers and thus different factors to consider related to the length of time it will take to decompose.

It takes anywhere from two to eight weeks for newspapers to decompose with the average being about seven weeks. This amount of time could be slightly slower or faster depending on temperature and soil conditions.

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