how to compost horse manure

Composting horse manure!


  • Let’s blow up some myths about this very easy process – compost will kill all of the things like worm eggs and create some great gardening soil for you.

What to do with horse manure at your barn.


  • This may largely depend on where you live and how your barn and farm are structured. In some parts of the country, there are actually companies that will come and pick up horse manure to be composted. I worked at such a barn, we had a big dumpster that was carted off as needed. Unfortunately, some farms don’t have services like this and the manure is hauled off with household trash.


  • Some farms have a random corner in a field to just pile up manure. Others have somewhat organized bins or bags for letting all of that horse poo turn into fertilizer. And then you have the super perfect bins that look like they were designed by a world-famous architect.


  • The point is, there’s more than one way to deal with horse poop, and if you are interested in how to compost horse manure, there are a few basics to know.


What are the benefits of using horse manure as fertilizer?


  • Composting horse manure is one thing that you can do at the barn that can help you create a “greener” environment. You are also going to save some dollars by not paying to have your manure hauled away, and your veggie growing neighbors and friends will be lining up to take it off your hands.


  • Because of the heat produced and bacterial action, composting can reduce the size of your manure piles by 50% or more. This same heat will also kill germs, bug eggs and larvae, and weed seeds. Compost will reduce the amount of gross run-off, and creates an easy way for you to spruce up your own barnyard and stable area.


How do I get started with a horse manure composting system?


  • A good location. High is better so that in the rainy months your pile is not sitting upon a puddle and thus becoming a giant poopy puddle itself.


  • Some containment. You can create compost in piles, you can also use bins. Think about 3 cubic feet (which is about the size of a very short fridge) for a few horses. You don’t want to go so big, as you will need to turn the piles. For more horses, just add more bins.


perfect horse manure compost

This super-wide compost bin has three areas – old, sorta old, fresh. Each is as wide as the tractor bucket for easy turning.


  • Consider having a few bins in a row – fresh manure, composting manure, and ready to go. As you fill one, the others can remain to do their thing. When you empty a “ready to go” bin, start filling it with manure from the bin before it. Then that empty bin gets filled with the contents of the first bin.


  • Piles are fine if you can manage the width – if the compost piles of manure get so wide and thin, they won’t compost. You will just end up with dry manure. The photos show a giant compost pile, you can see the older compost surrounded by fresher smaller piles from the wheelbarrow. This is not an ideal situation for getting good compost, but it can work if you have space and a very large tractor to turn it.


  • Cover it. Tarps are great, as are lids to a bin. This keeps the heat in! You might find that in some parts of the country, you don’t need to cover it.


  • Keep it aerated. An easy way to do this is to place PVC pipes with holes drilled into them into the piles like chimneys. Turning the piles will also aerate the compost.


  • Part of the benefit of composting in bins is that your piles are reduced in size. Without cover, regular turning, and getting oxygen to the insides of your piles, you won’t reduce the size as much and it all takes longer.


pvc pipe with holes for compost bin

This pipe is about 5 inches in diameter – and it has holes to help aerate the compost. No need to jam this into the compost, you can create a pile around the pipes.


  • Keep your compost damp, not wet. If you live in the desert, you may need to add some water.


  • It’s totally OK to use your compost bin for eggshells, coffee grounds, hay bits, organic garbage, banana peels, and even hair from a clip job on your horse! Don’t add any meat or oils you are good to go.



large compost pile in a field

This compost area is just a big pile, and it takes infinitely longer to break down as it’s not cared for.


  • The point of doing all of this (turning weekly, keeping damp, covering the compost) is to create that great environment for all of the microbes to eat the organic matter and break it down. This creates the heat, and the really nice fertilizer in the end.


  • Your compost should not smell. It also won’t attract flies. If you smell ammonia or are seeing a bunch of bugs, you need to adjust the moisture by letting it dry out a bit and turn it more frequently.


narrow compost bin in sunshine

This is a small compost bin, about the width of a tractor, that is turned about once a week so covering is not “mandatory”.


  • Turning the piles can be done a few ways, the easiest is to move it from one bin to the next, so the top of the pile becomes the bottom of the next bin. You can also stir it up by hand, or use a tractor scoop to mix it up.


  • You can also “seed” your first manure pile with a composting formula from your local garden supply store. I also suggest that you work with your local garden expert to advise you on the best composting methods for your climate and your ingredients.


  • Wood shavings in the compost can be done – but may alter the nitrogen content of the compost. It will also make your compost more like mulch, versus the dirt consistency of just composting manure. But – you will never be able to keep all of the shavings out, and it’s no big deal.


But what about parasite eggs and deworming meds that remain in my horse’s poop?


  • The consensus is that when your compost pile can heat up to 140 degrees F for a few days, all eggs and larvae of horse parasites will be dead. This is key to stopping the spread of intestinal parasites.


  • For the remnants of dewormer, this takes days and weeks to fully decompose some of the ingredients contained in deworming meds. Don’t worry – by the time your compost is ready for the garden, they will all be gone.


How long does it take to compost horse manure?


  • It could be weeks, it could be months. This really depends on how you design and manage your compost system. Take into account how the piles are managed. Smaller piles that are turned weekly and have good moisture levels and oxygenation will decompose faster.


  • Larger piles that are dried out, not turned regularly, and not maintained could take months or even a year to achieve the same effect.


  • Compost piles that contain a lot of shavings will also take longer to become ready. Larger flake shavings take longer than sawdust, too. It may be quite a few months before piles like these are ready.


Making a compost system at your barn doesn’t have to be a huge project. You can easily set up some test areas with muck tubs as bins if you want to see how the process works and go from there. And just think of all of the wonderful veggies you can grow!


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This is some compost starter, it would be good for a small “trial run” of compost at your barn.

A book – all about horse poo.

A book for the horse lover and gardener!