How Long Does It Take for Pine Needles to Decompose? | 6 Tips for Compost

If you have a pine tree in your yard, you likely wonder at times what to do with the seemingly unending supply of needles that is constantly on the ground. Pine needles might not look that bad, but when they start to pile up and you can’t seem to get rid of them, composting them is always a good idea.

It takes from 3 weeks to 2 months for pine needles to decompose. You cannot just throw them into your compost pile but there are a few simple steps to follow to prepare them.

If you decide to compost your pine needles, here are six tips that will make it easier.

1. Keep pine needles to less than 10% of the mix

We’ve all heard about brown versus green composting materials, and the proportions are especially important when you’re using pine needles in your compost. The recommended number is 10%, which means that no more than 10% of your compost pile should consist of pine needles.

Remember that pine needles decompose very slowly, which means that it’s important that they be mixed with a good variety of other composting materials if you want to produce a healthy soil in the future.

2. Remember that pine needles are acidic in nature

Most compost piles tend to be naturally alkaline, but pine needles are slightly acidic. There is a myth out there that pine needles will cause your soil to become acidic, but that is not the case.

When pine needles are fresh and green, they usually have a pH of 3.2 to 3.8, but once they fall off of the tree and start to decompose, they start losing their acidity. Keep in mind that the pH scale goes from 1 to 14, with the lower numbers being more acidic and the higher numbers being more alkaline.

Most plants prefer soil that has a neutral pH, but once the pine needles fall off the tree and start to decompose, they end up with a pH that is fairly neutral at 5.6 to 6.0. In fact, the longer you keep pine needles in your compost pile, the more neutral they become.

For this reason you don’t have to worry about the soil being ruined because you’re putting your pine needles in it. You will still have to make sure that you don’t put too many pine needles in there, but you’ll be fine as long as you keep the proportions correct.

3. Add 3 things to your compost pile with pine needles

Regardless of what you intend to put in your compost pile, remember that all compost piles need three things:

  • The right amount of moisture
  • The right amount of oxygen
  • The right mix of brown and green materials

Moisture is a must because it helps feed the bacteria that are necessary for pine needles to decompose. Oxygen is a must because this allows the microbes to do their job correctly. In other words, all of these things have to work together to produce a healthy compost pile and soil that can feed your plants the nutrients they need to grow and thrive.

Green materials have a lot of moisture, decompose quickly, and contain a lot of nitrogen. Brown materials are higher in carbon, take longer to decompose, and provide some structure to the compost. This is why both of these types of materials are so important.

Tip 4. Special treatment for large pine branches

Before adding large branches filled with pine needles in your compost pile, take some pruning shears and cut them into small pieces first. If you have a lot of small branches and needles, place them in a shredder or wood chipper to make them as small as possible.

The smaller the branches and needles are, the less time you’ll have to wait for them to decompose. Larger needles and branches will naturally take longer to decompose than smaller ones will, so making sure that they are as small as possible is always a good idea.

This mix can also be used as a mulch and placed on the soil surface to block weeds and keep soil moisture in.

5. You can speed up the breakdown process of pine needles

Just as making sure the needles and branches of your pine tree are broken up into pieces that are as small as possible, you can do other things to speed up the decomposition process.

Soaking your pine needles in water for 24 to 48 hours before placing them in the compost pile will help them to break down fast.

If you have lots of pine needles. Set them aside and add them gradually to your compost pile. Regardless of what you do, soaking the needles in water first can help speed up the decomposition process.

6. Avoid adding fresh pine needles to your compost

It is best to allow pine needles to dry off for a few weeks at least before adding them to your compost pile. Chop them in small pieces and add up to 10% to the mix. Fresh pine needles can also be covered in sap so let them dry and it will be easier to mix them through your pile.

Check out this amazing compost made with pine needles and grass clippings.


Pine needles have a low moisture level, are considered brown composting material, and have a relatively poor structure. Since pine needles break down slowly, they can help maintain the form of the compost and introduce oxygen into the compost pile because they improve air circulation.

Since the acidity in pine needles gets lower the longer they are decomposing, there is no need to become concerned about the acidity level of the needles ruining the soil.

Just make sure that your compost pile is no more than 10% pine needles and that you mix your compost pile well and your compost pile will be nice and healthy before you know it.