Are Pine Needles Good for Your Compost?


I have been preparing compost for the next growing season, and since I have collected fallen pine needles, I thought I should add them to the compost. However, I was conflicted after some research because I discovered several arguments for and against using pine needles in compost. 

Pine needles are good for your compost because even though they are acidic (pH 3.5), they don’t change the pH of the compost. They are also nitrogen-rich. However, the wax coating keeps them from decaying, so they take a long time to break down. Fortunately, cutting them speeds up the decay process.

In this article, I’ll discuss the arguments for and against using pine needles in compost. I’ll also analyze ways to improve them to make them compostable. 

Why Pine Needles Are Not Good for Compost

Before adding pine needles to your compost, you should understand why some people argue against it. Once you know the issues with pine needle composting, you will work around them. 

Here are the features that make composting pine needles difficult.

  • The wax coating is the reason why pine needles don’t decompose quickly. Microbes cannot penetrate this coating. This is why fallen leaves remain the same for a long time. If you compare pine needles with other types of leaves, you’ll notice other leaves crumble when dry, yet pine needles only fold without breaking. 
  • Pine needles form a blanket-like cover, limiting oxygen circulation. This is why pine needles that fall on the ground take too long to decay. When used in compost, pine needles encourage anaerobic composting, which usually takes a long time to decay. The compost heap will also be smelly and produce methane gas. 
  • They have a low pH of 3.2 – 3.8. The high acidity is one of the arguments against pine needles. However, pine needles lose acidity over time, attaining neutral pH by the time they decompose. The challenge is with fresh pine needles because they interfere with the microbial activity in the compost. 
  • Pine needles have low moisture levels. Compost needs moisture for the organic matter to decay quickly. Unfortunately, the wax coating found on pine needles prevents water absorption. 

Fortunately, you can work around these issues to make the pine leaves work for your compost. 

This video analyzes some of the myths around composting pine needles, including its pH and impact on the compost.

How To Use Pine Needles in Compost

Pine needles may have shortcomings, but it doesn’t mean they are entirely useless. You can still collect the fallen leaves and add them to your compost. However, you must be careful when using pine needles in your compost.

  • Cut the pine needles into small pieces. These will decay faster because the microbes will start breaking down the pine needles. The wax coating keeps the microbes from getting into the leaf structure, but once you break the leaves, you open them up for decay. 
  • Pine leaves should make up 10% or less of the composting material. Since they decay slowly, you don’t want to add many pine leaves to your compost because the compost will take a very long time to decompose. 
  • Avoid using fresh pine leaves to represent the green components in compost. Green pine needles are rich in nitrogen but they’re also highly acidic. When added to compost in this state, they will interfere with microbial activity. Instead, you should use dry pine leaves. By the time they decay, they would be closer to a neutral pH of 5.6 – 6.0.
  • Mix pine leaves with green material for faster composting. If you are composting large branches, use a wood chipper or pruners to cut them into smaller pieces. 
  • If you have collected a lot of pine leaves on your property, consider composting them separately from other organic materials. Collect the pine in a heap and run your lawn mower over them. They will decompose faster. 
  • Ensure you know the source of the pine needles before using them. If they come from your backyard, they may be suitable for composting. However, if they were swept from the road, they may contain heavy metals. Sometimes dog droppings may be found within the needles, so you need to ensure there are no contaminants that will compromise the compost’s quality. 
  • Go for old pine needles or those that you used as mulch for at least a season. The wax in pine needles used as mulching would have broken down, which is why they decompose quickly. 

Pine needles are a challenge to use in the compost. However, you can work around the issues that make it difficult for them to decay, and you will end up with great compost. 

How Long Does It Take To Compost Pine Needles? PAA

Before adding pine needles to your compost, you need to know how long they will take to decompose. When preparing compost, you probably have a plan regarding when to use it. However, you need to remember that pine decomposes slowly.

How long it takes pine needles to decompose varies depending on the conditions. A pile of pine needles in a dry area will take years to decay due to low moisture levels. However, compost with enough green material, household ammonia, and heat will decompose pine needles within a few months. 

Although the physical attributes of the pine needles inhibit fast decay, you can counter these shortcomings to speed decomposition. The bottom layer usually decomposes faster because of moisture, heat, and microbial activity. 

I have piles of pine needles, and I chose to add Green Pig Compost Accelerator (available on Amazon). This natural compost accelerator speeds up decomposition, generating nutrient-rich compost in a mere 4weeks. It also helps in reducing the odor from the compost piles. 

How To Speed Up Composting

Although organic materials decompose at different rates, you don’t have to wait too long before you can use the compost. You can take several measures to speed decomposition, especially when using pine needles.

  • Add household ammonia to the compost. The best carbon to nitrogen ratio is 30:1. When nitrogen is available at a higher ratio, the compost will release a lot of ammonia gas, resulting in a smelly compost. Sometimes the nitrogen levels are too low. Fortunately, household ammonia increases nitrogen levels, hence speeding up decomposition. 
  • Make a large compost pile. Heat is crucial for compost decomposition. The larger the pile, the greater the heat retention. The compost will also retain more moisture, further speeding up decay.
  • Shred all the brown and green material. Leaves decay slowly, but pine needles take longer compared to other leaves. To speed up compost decomposition, you should shred everything. You’ll create more air spaces for oxygen circulation, increasing microbial activity.
  • During the dry season, add water to your compost. Dry compost doesn’t decompose quickly. However, when adding moisture, don’t add too much water because it will cause the compost pile to rot too quickly. It will also reduce the air spaces and encourage anaerobic bacteria to take over, resulting in smelly compost. 
  • Cover your compost during the rainy season. You don’t want it drenched with water. The compost pile should only be about 40 – 60% water. The best way to test the water level is to squeeze the compost. If you squeeze out some water, it is the correct moisture level. If it is too soggy, the compost is too wet. 
  • Occasionally turn the pile over. This encourages aeration and even decomposition. The compost will produce more aerobic bacteria when you introduce fresh oxygen into the compost pile. You will also control the temperature better because anaerobic bacteria will take over when the compost gets too hot. 
  • Add worms to the compost. Worms will feed on the organic matter and speed up decomposition. 

You can use the household ammonia to help increase the nitrogen in your compost pile.

Conclusion

Pine needles are a great addition to compost, but you should be wary of their shortfalls. 

If you have pine trees, you don’t have to dispose of the fallen leaves. Instead, shred and pile them or add them in small quantities to the compost. You can also take measures to speed compost decomposition.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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