Throughout the year, evergreen trees drop needles. You can compost pine needles but it is a pretty slow process. One way to speed up the decomposition process is to break them into smaller pieces to increase the surface area. They will turn into useable compost in around 3 months if you have an active compost pile. This guide explains how to compost pine needles and pine cones, step-by-step. I’ll also explain some benefits and drawbacks using pine needle compost.
Can You Compost Pine Needles?
Yes. You can compost pine needles. They are completely organic. They will break down over time in your compost bin. Once they’ve decomposed, you can use the compost in your flower beds and vegetable garden. They make fine compost.
Ideally, pine needles should never make up more than 10% of your compost pile. The reason is that pine needles break down extremely slowly. Pine needles decompose slowly because they have a waxy coating. This coating is designed to protect the needles during the cold winter months. Bacteria and other decomposers have a hard time processing the coating.
There are a couple of ways to speed up the decomposition process. Mixing pine needles with other materials that break down faster can help speed up the decomposition. The faster decomposing materials will help heat the compost and promote microbial activity to make the composting process faster. Some materials you can mix with the pine needles include grass clippings, kitchen waste, shredded leaves, newspaper, and coffee grounds.
Another way to speed up the decomposition process is to break the pine needles up into smaller pieces. This increases the surface area. It also helps break up the waxy coating. This way, there will be more area for the decomposers to work on. This greatly increases the rate of decomposition.
Pine needles aren’t the best material for composting but you can use them. If you have pine trees on your property, you might as well add some of the fallen needles to your compost bin. They add some nutrients and organic matter to your compost.
You can also compost pine cones. They take a long time to break down unless they are ground up into smaller pieces.
Do Pine Needles Make Your Compost Acidic?
A common misconception is that pine needles make soil acidic (lower the pH of the soil). There is some truth to this. Fresh green pine needles are acidic. They usually have a pH of 3.2-3.8. They may lower the pH level of your compost slightly.
As pine needles age and start to break down, they quickly become neutral. Decomposing pine needles have a pH of 5.6-6. To compare, a pH of 7 is neutral. Most finished compost has a pH of 6-8. It can be slightly acidic, neutral, or slightly alkaline, depending on which feedstock was used.
Most plants prefer soil that has a neutral pH to slightly acidic. Soil that is too acidic can affect the health of your plants. If your soil is already acidic, adding pine needles could make it slightly more acidic. The change is usually negligible. If you are growing plants that prefer alkaline soil, you may be better off not using compost that was made from pine needles. Even then, the compost is unlikely to have any harmful effect.
There are some plants that prefer acidic soil. Acid-loving plants are known as ericaceous plants. Some gardeners keep two separate compost piles. One for regular materials and one for acidic materials. The acidic compost is great for plants that prefer acidic soil. Some examples include Rhododendron, Camellia, and Azalea. Pine needles work great in acidic compost.
If you’re concerned about the pH of your soil, you can test it with a soil pH meter. These are available on Amazon and in garden centers. You could also pay for a soil test. Many companies offer them. You just mail in a soil sample and wait for the results.
How to Compost Pine Needles
To make good compost, you need a good mix of compost materials. Compost is made from a mix of ‘green’ and ‘brown’ materials.
Greens are high in nitrogen. They also have a high moisture content. They decompose quickly. Some examples of greens in compost include grass clippings, coffee grounds, kitchen scraps, etc.
Browns have a high carbon content. They take a longer time to decompose. These materials help provide structure for your compost so air can circulate through it. Examples of browns include pine needles, dry leaves, and newspaper.
Generally, a good ratio for your compost mix is 3:1. 3 parts brown feedstocks for every 1 part green feedstocks. You could also use a 2:1 ratio or even a 1:1 ratio.
To make compost, you also need oxygen and moisture. Oxygen and moisture are necessary for the compost to undergo aerobic decomposition.
Once in a while, you’ll have to mix your compost to oxygenate it. You’ll also have to add some water so it doesn’t dry out. Maintaining the proper amount of oxygen and water will speed up the decomposition process.
Pine needles are considered a brown material in composting. They provide a good amount of structure. The rigid needles help create air pockets in the compost. They are also high in carbon and low in nitrogen.
The best method for composting pine needles is the hot composting method. Hot composting speeds up decomposition. The heat is generated by microorganisms that are breaking down the material.
When selecting pine needles to add to your compost, try to add the older, dry needles first. They will be less acidic than fresh pine needles. They also may have already started to decompose. This will speed up the decomposition process. If you only have fresh needles, consider letting them age before adding them to your compost.
To compost pine needles:
- Shred the pine needles- Whole pine needles take a long time to break down. Shredding them will increase the surface area and speed up the decomposition process. If you can’t shred them, you can still use them. Just know that they won’t compost as quickly.
- Add the pine needles to your compost bin or pile- When you first start composting pine needles, start out with a small amount to see how they work. Ideally, pine needles shouldn’t make up more than about 10% of your compost. This will make for a healthy compost pile. If they work well, you can increase the amount of pine needles if you choose.
- Mix regularly- You want to keep your compost aerated. Ideally, you should mix your compost every 3-4 days. If you don’t, it can start undergoing anaerobic decomposition if there isn’t enough oxygen. This is not ideal. It can cause your compost to stink. It will also become too acidic.
- Monitor the moisture level- Your compost needs to stay moist. During the summer, it will dry out quickly. You may need to spray it with the hose every couple of days. At the same time, you don’t want your compost to be too wet and sloppy or it could attract pests or start to mold.
How to Shred Pine Needles
Before adding pine needles to your compost, it’s a good idea to shred them. This will help break up the waxy cuticle coating. It will also increase the surface area available for decomposers to work on. There are a few ways to shred pine needles including:
- Use your lawn mower- Just lay them in a layer on your lawn and mow over them. You may need to mix them a couple of times to hit them all.
- Use a leaf shredder or a wood chipper- You can collect the shredded needles in a bucket and add them directly to your compost bin. You can also shred pine cones and compost them if your shredder is capable.
- Use a leaf blower- Some leaf blowers are capable of shredding pine needles. The motor reverses and sucks the pine needles up and shreds them with a blade. They are then collected in a bag.
Why Compost Pine Needles?
Composting is a good way to get rid of pine needles. If you have pine trees on your property, you’ll have a lot of them. A Ponderosa Pine tree drops ¼-⅓ of its needles every year. Usually in the fall. If you compost part of them, you’ll have fewer to get rid of.
It’s also best not to leave a thick layer of pine needles on your property because they can be a fire hazard. When pine needles catch fire, they burn quickly. If you live in an area where wildfires are a problem, it’s best to remove pine needles. Once they’re composted, they are less of a fire hazard.
Another nice thing about pine needles is that they are a clean material. They are completely natural. You know they weren’t treated with any chemicals. Of course, they are also free and widely available.
Pine needles also aren’t that attractive. They can be kind of an eyesore when they’re lying around on your property. When you compost them, they just look like soil.
Of course, the biggest benefit is that you get to use the nutrient-rich compost in your garden. Using compost is a great way to improve plant growth.
Drawbacks of Composting Pine Needles
The biggest drawback of composting pine needles is that they take longer to break down than other materials such as leaves or grass clippings. If you shred the pine needles, they should break down in around 3-4 months. If you have a hot and active compost bin, they may break down in as little as 6 weeks. They could take longer if your compost is less active.
Another potential drawback is that pine needles aren’t very nutrient-rich. They are mostly made of carbon with a small amount of nitrogen. The carbon-to-nitrogen ratio is around 100:1. You will need to mix in some high nitrogen green materials in with the pine needles to make quality compost.
Compost made with pine needles may also be slightly more acidic than average. By the time it’s ready to use, it will be very close to neutral.
Using Pine Needles as Mulch
You don’t have to compost pine needles before you use them in your garden. You can just use them as mulch. They make a great ground cover. Apply a layer 3-4” deep in your garden around your plants. When used as mulch, pine needles are often referred to as pine straw.
The pine needles will help with moisture retention by reducing evaporation. They will also help suppress weed growth by blocking weed seeds. Pine needles will also insulate the garden soil from the heat and cold. In addition, they will also reduce evaporation and soil compaction. Over time, they will break down and add some nutrients and organic matter to the soil, just like they would when making compost. They don’t contain as many nutrients as other types of mulch but they are still beneficial.
Mulching saves some time. You don’t have to wait for the pine needles to break down in your compost. You can use them immediately. Before using pine needles as mulch, you should allow them to age a little bit. Aged pine needles aren’t as acidic. The pine needle mulch will last a long time.
It’s best not to use pine needles as mulch near your home in case of fire. They can be a fire hazard. They also aren’t ideal for use on slopes because they can become slippery when they’re wet.
For more in-depth info, check out my guide: Using Pine Needles as Mulch.
Composting Pine Cones
You can also compost pine cones. They decompose very slowly. You will want to find a way to break them up into small pieces to speed up the decomposition process.
Pine cones can be difficult to shred because they are so tough. Most leaf shredders and wood chippers are capable of shredding pine cones. If you don’t have a shredder, you can break them up with a hammer if you don’t have too many.
Once the pine cones are broken up, you can add them to your compost or use them as mulch. They will break down and add nutrients and organic materials, just like pine needles. They will likely take a few months to decompose. Pine cones can make fine compost or mulch.
My Experience
I have several large pine trees on my property. They produce tons of pine needles. I usually rake the needles around the base of the trees. Once in a while, I collect some to add to my compost. I have a leaf shredder I use to shred them into smaller pieces before I add them. They break down surprisingly quickly. Within about 3 months, the compost is ready to use. Even if the pine needles aren’t completely broken down, I can still use the compost. The partially decomposed needles improve the soil structure. I also use some pine needles as mulch so I don’t have bare ground in my garden.
Pine needles can make quality compost. There is nothing wrong with using them. They will add essential nutrients to your compost. They are a great source of organic matter. The main drawback is that they take longer to break down than other materials. The decomposition rate of pine needles is slow. You can speed up the process by breaking them into smaller pieces. If you don’t want to wait, you can use them as mulch. They will break down over time in your garden. Whether or not you decide to compost pine needles, I hope this guide has helped you in making your decision.
Do you compost pine needles? Share your experience in the comments below!
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