Horse Manure: From Road Apples To Fertilizer

Horse manure in snow


There’s a lot of different names for horse manure! Horse buns, horse chips, horse hooey, horsepucky, or our favorite, road apples. To some, it’s just a mess that needs to be cleaned up.

But to a gardener, all that waste is some of the best organic fertilizer available. Sure, it needs to be mucked out of the stalls, then composted to cure it first. But once it’s done, it’s phenomenal.

Today we’ll get down and dirty with this farm-raised fertilizer. By the time we’re done, you’ll know all there is to know about this rich additive!

Small Supplies Of Horse Manure At Amazon:

What Is Horse Manure?

Horse manure in snow
A pile of horse manure in the snow. Source: andyarthur

Slightly higher in nutrition than cow or steer manure, horse manure is exactly what you think it is. Horses eat, horses poop. But that’s not all that’s in horse manure.

The term “manure” also includes small amounts of wood in the form of shavings or sawdust, or other material like straw or hay. These bedding materials are generally strewn around stables to absorb horse urine. When the stables are cleaned, everything is then removed and piled up. True horse manure includes the bedding materials as well as absorbed urine along with the poop itself.

This raw material isn’t ready to use yet. Fresh horse manure is often alkaline, and it requires composting to prepare it further and bring it to a more neutral state.

Horse manure may contain bits of undigested plants and grasses, seeds, and the like. Any seeds which are present should become sterile through the hot composting process. The plant materials become valuable organic matter in the soil.

Sadly, manures have gotten a bit of a bad rap in recent times. Concerns about antibiotics or medications making their way into the manure are widespread. Due to those concerns, many people have started to avoid it, although they shouldn’t. In most cases, the composting process will remove any residual medications. Those who’re really concerned should talk to horse owners. That way, they’re sure to get manure free of unwanted additives.

Benefits Of Using Horse Manure

Bagged horse manure
Bags of aged and composted horse manure, ready to use. Source: Kirsty S

If you’re looking for a true, organic solution, horse manure is about as organic as you get… to a point.

When horses eat grass, they are eating anything which is on the grass. That includes herbicides and the like. But most riding horses are more spoiled, and have good-quality grains and hay. This ensures their manure is less likely to carry any residues.

Beyond being organic, it’s also easy on plants. Unlike chicken manure or others, fresh horse manure is unlikely to burn or damage plants. It’s high in nitrogen, but much of that nitrogen is tied up in undigested plant material. While it provides an immediate nitrogen boost, much more will be slowly released.

Fertilizer ranges vary depending on what the horse has eaten. A good baseline estimate is 0.7-0.3-0.6, but it can be higher or lower.

It’s a fantastic soil builder as well. All that organic material will bulk up the soil, helping to store moisture. It also ensures that excess water will drain off well, making it a good conditioner for clay soils.

Not as pungent of a scent as other manures, a pile of manure will smell, well, horsey. It’s not a bad aroma compared to other organic options.

And best of all, it tends to be cheap. If you can find someone who raises horses, they’ll usually let you haul some of their pile away. The average horse produces nine tons of manure a year. Needless to say, anyone with a few horses or especially a herd will have an ample supply!

Drawbacks Of Using Horse Manure

Horse manure fresh and composting
Fresh horse manure can have lots of weed seeds. Source: adstream

Raw, fresh manure tends to be very high in nitrogen. Often, it’s accompanied by a good dousing of urine, which has lots of urea. Some plants, such as roses, will adore the fresh manure. Others may find it to be a bit too much.

Uncomposted horse manure has another drawback. It tends to be alkaline, which means that acid-loving plants such as blueberries may not like it fresh. As it breaks down, it neutralizes, becoming a good additive for all plant types.

And finally, if the horse has been grazing in a field, they’ve likely eaten weeds. Horses are notoriously poor at digesting their food. You can often recognize what they’ve been eating by looking at their manure. This means that weed seeds are likely to appear.

Composting horse manure is an easy-sounding solution for most of these problems. Due to the large amount of raw material in their waste as compared to other animals, though, this can take a while. It’s a slower composting process than cow or chicken manure.

Horse manure should be hot-composted to kill off any weed seeds inside of it. While hot composting isn’t difficult once you know how to do it, learning how to keep your pile hot takes practice.

How To Compost Horse Manure

Composting horse manure may seem like a bit of a chore, especially if you have a lot of it! But this creates a rich and valuable resource that gardeners crave.

There are a couple of methods that will produce weed-free compost. Hot composting is the most common method. Vermiculture is the alternative. Both will render the compost clean of weed seeds or harmful bacteria.

Hot Composting Horse Manure

Horse manure composting
Large pile of horse manure composting down. Source: hajee

To hot compost, you will need enough horse manure including bedding material to make a large pile. Ideally, it should be at least three feet tall by about the same diameter wide. You can build larger piles, but they will take more work.

When you are piling your horse manure, make the pile into a cone or domed shape. Once it’s in place, use a hose to wet down the pile thoroughly. If you’re expecting a lot of rain, place a tarp over the pile, or compost it under a roof.

Check your pile with a compost thermometer to make sure the center of the pile heats up. The ideal temperature should be at or around 130 degrees, as this will sterilize seeds. If the weather is cold, putting black plastic over the pile may increase the heat inside.

Once the inside of your pile has been at 130 degrees for at least three days, it’s time to turn your pile. Remove all the material from the outside of the pile first, starting a new pile next to the old one. A compost fork or scoop shovel can be used for this purpose.

Then, the hot material from the center of the pile should be put on top of the cooler material. This ensures that all the uncomposted material from the exterior now has a chance to cook down, too. Again wet it down, and check it with your compost thermometer to make sure it heats up.

Once all the material has been through 130-degree heating for at least three days, you’re nearly done. Your compost is ready once it looks like dark, loamy material. Individual “road apples” should be hard to identify or should break apart when touched.

Another identifier that your composted manure is ready is the smell. Fresh manure smells like horse poop, straw or grass, and wood. Composted manure should smell like soil.

One thing to be watchful for: hot compost piles can actually get too hot. If your pile is steaming on a cold morning, that’s fine, but if it starts to smell burned, add more water. You’re trying to keep it hot enough to kill pathogens and seeds, but not hot enough to combust.

Vermicomposting Horse Manure

Horse manure and newspaper worm bedding
Horse manure and newspaper worm bedding. Source: Vermi Chaval

Worms love horse manure! In fact, some of the best worm colonies live in bedding made of horse manure. Eisenia fetida, the common red wiggler, is also referred to as the “manure worm”, and that’s what a lot of worm farms raise their worms on. But there’s a trick to these.

Rather than starting with fresh manure, it’s best to begin with aged manure. This is horse manure that has been sitting in a pile for a while, occasionally watered down. But it’s not cared for as carefully as a hot compost pile would be.

Aging the manure gives it time to get past its tendency to create heat. Wetting it down regularly rinses out any deworming medication the horses might’ve had and reduces ammonia buildup in the manure. It may still smell slightly horsey, but it’s often half-composted.

When it’s at that point, you can use it as bedding for your worm bin, and the worms will be quite happy in it. They won’t need worm food for at least a couple of weeks as they settle into the bedding. There’s plenty already there to eat.

If you’ve got small amounts of fresh manure, you can also put a 2-4″ layer on top of an existing worm farm. The worms will eat the fresh manure as much as they would aged manure, but it’s less likely to heat up in a thin layer. Never add more than a 4″ deep layer, especially in a home worm bin. It’s just too hot for the worms to handle.

As the worms consume the manure, they make manure of their own. This vermicompost is extremely dark and fine-grained. It can be worked straight into the garden or used to make compost tea.

Can Horse Manure Be Composted Other Ways?

Horse manure
A batch of fresh horse manure. Source: bionicteaching

While the above methods are the most common, they’re not the only options open to the home gardener.

For people who are using a no-till or lasagna gardening method, fresh horse manure is great. It should be treated as a “green” material. Alternate these green layers with “brown” layers of carbon-rich material. Cardboard, paper, wood shavings, straw, or dry leaves are often used as browns.

After applying fresh manure to your lasagna or sheet garden, you should allow it to break down for at least a month. This gives it time to get through the initial heating and cooling period, and it’ll be safe to plant in.

People who do till their gardens can compost manure directly in their beds, as well. Pick a time of year when you don’t plan on planting in that bed. Till the horse manure into the soil, being sure it’s well incorporated. Cover the bed with a sheet of black plastic to prevent weed germination.

It’s possible to compost horse manure in a compost tumbler too. If you’re an urban gardener, you may be able to visit the local stable and fill up a five-gallon bucket of manure. Work that into your tumbler additives with an ample supply of brown material!

What If You Have A Lot Of Manure To Compost?

Moving horse manure with tractor
Moving composted horse manure with a tractor. Source: petehoffswell

If you’ve got a ranch, or own a stable, you’re going to have a lot of manure. There’s no way to get around it. A horse can produce 30-50 pounds of manure per day, every single day.

Most people with that sort of volume use a hybrid hot composting method. They find a way to aerate the pile from underneath, rather than turning it. This gives all the compost a chance to heat up except for a thin top layer.

A few great methods for building this hybrid hot composting system can be seen in the video below. Remember, all that manure can later go straight out into the pasture to fertilize it! And you’ll always have plenty of people willing to take your composted manure, too.

YouTube video

How To Use Horse Manure

Using horse manure in the garden is easy, and can take multiple forms. You can use it solely as a fertilizer, as a soil amendment, or even as the soil itself. It also can be an effective liquid fertilizer.

Before planting, you can spread composted area over your soil and till it in. This gives your plants a kickstart of nutrition.

What if your garden’s already planted? Add composted horse manure as a top-dressing. 1/2″ to 1″ is perfect. Water it in well, and it will continue to break down on the surface.

For individual plants, a handful or two can be applied around the base of the plant. Use your hands or a cultivator to work it into the soil’s surface.

Are you starting a new raised bed? If so, and you’re not in a hurry to plant it, fill it with horse manure and brown materials. Allow it to compost down on its own, and the next year you can plant directly into it!

It can also be applied as a horse manure tea. Take some fresh horse manure and add it to a small bucket of water. Close the bucket and shake it, or stir it with the lid off. Regularly mix until the manure has almost completely dissolved into the water.

You can strain off any remaining solids and use that manure tea to fertilize your plants. If you want to use it in place of your regular watering, dilute it a bit and use it every time you water.

Are roses your favorite flower to plant? If so, you’re in luck. Roses love the alkaline nature of fresh horse manure! Apply fresh horse manure around the base of your roses and water it in. Within a year, you’ll be hard-pressed to tell where the manure ends and soil begins.

Mushrooms love horse manure, and one of the most popular mushroom substrates is a 50/50 mix of manure and straw. If you’re trying to grow mushrooms, you might like this blend!

I can tell you firsthand that turnips, squash, and watermelons love horse fertilizer. I have used it for several years as my only fertilizer and have grown some very healthy vegetables.

Where To Get Horse Manure

Moving horse manure by wagon
A wagonload of manure. Source: cindy47452

Now that you’re sold on this stuff, the next question arises: where to buy horse manure. And you don’t always have to buy it!

Your best sources for horse manure, if you don’t mind composting it yourself, are stables. If you know someone with a horse, this may be as easy as calling them up and asking. Otherwise, contact local farms or ranches, or even your local riding facility.

Often, people will post online that they’ve got manure available. Sometimes it’s free. Other times, there will be a small fee or delivery charge. It’s simply a matter of getting in touch!

But what if you’re looking for just a small quantity to use as mushroom substrate? Or a bit to add to your worm bin or as fertilizer for your house plants? There are options for you, too.

The Clayton Farm produces five-pound bags of composted and aged horse manure. This is perfect for people who want to make horse manure tea or top-dress houseplants.

Another supplier, SpiritOne, promises fully organic and thoroughly-dried horse manure. Because it’s completely dry, you’re getting all manure with no water weight. This is a great starter for a worm bed.

Mushroom growers will love Out Grow’s mushroom substrate mix. It’s a blend of aged and composted horse manure with straw, and is fully sterilized and ready to use. Just add mushroom spores and you’re good to go!

You may sometimes be able to find bags of composted horse manure at a local garden center. This varies depending on your area, and isn’t always an option.

For the largest amounts, you’re likely to have to compost it yourself. But at least it’ll be very inexpensive to get, provided that you put the legwork in on finding a source.

They say never to look a gift horse in the mouth… but maybe we should be looking more at the other end of the horse! What was once a very common waste product is a very beneficial additive to our gardens now.

Last update on 2024-04-10 / Affiliate links / Images from Amazon Product Advertising API

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