Yes, you can absolutely use horse manure in your garden, and it can be a great way to improve your soil. However, you should not use it fresh or “hot” directly on your plants. Raw horse manure needs to be aged or, better yet, composted first to make it safe and beneficial for your garden soil. Using aged or composted horse manure as fertilizer is a long-standing practice that can bring many benefits to your plants and the earth they grow in.
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Deciphering Horse Manure for Garden Use
Gardeners look for ways to make their soil better. Good soil grows healthy plants. One thing that can help is adding organic matter. This means adding things that were once alive, like leaves, grass clippings, or animal waste. Horse manure is animal waste. It comes from horses. Many gardeners use it.
But not all organic matter is the same. Animal manures differ. They have different amounts of plant food, called nutrients. They also behave differently in the soil. Using horse manure in garden soil is popular. It can be easy to find if you live near stables.
Benefits of Horse Manure for Soil
Adding aged or composted horse manure to your garden gives it many good things. It acts like a soil builder. It also feeds your plants slowly over time.
Boosting Soil Health
One big benefit of horse manure is how it helps your soil. Soil is more than just dirt. It is a living system. Good soil has structure. It holds water but also lets extra drain away. It has air pockets for roots to breathe.
Adding composted horse manure makes soil structure better. It adds organic stuff that helps sandy soil hold more water. It helps clay soil become looser and drain better. This means roots can spread out easier.
Feeding Your Plants
Horse manure is a natural fertilizer. It has nutrients that plants need to grow strong. These include important ones like nitrogen, phosphorus, and potassium. It also has other small amounts of nutrients, called micronutrients.
These nutrients are not released all at once. They break down slowly in the soil. This gives plants a steady food supply. This is different from some chemical fertilizers. Chemical fertilizers can give plants a quick boost. But they can also wash away easily. Natural fertilizers like composted horse manure work longer. Using horse manure as fertilizer adds these nutrients in a slow, gentle way.
Inviting Good Microbes
Healthy soil is full of tiny living things. These are microbes. They include bacteria and fungi. These tiny things break down organic matter. They turn it into food for plants. They also help fight off plant diseases.
Adding composted horse manure feeds these good microbes. More microbes mean healthier, more active soil. This helps plants get the food they need. It also makes the soil more able to fight problems.
Drawbacks of Using Raw Horse Manure
While horse manure is good for gardens, you cannot just shovel fresh manure onto your plants. Fresh manure has problems. These problems can hurt your plants and garden. This is why it’s called hot manure in garden talk.
The Problem of “Hot” Manure
Fresh manure is called “hot” for a reason. It has a lot of nitrogen. This nitrogen is in a form that can burn plant roots. It also causes a lot of heat as it breaks down. Putting fresh, hot manure right next to plant roots can damage or even kill them.
Imagine putting something very hot next to delicate plant roots. That’s what using fresh manure can do. This heat and strong nitrogen content is why it needs time to age or compost.
Bringing Unwanted Guests
Horses eat grass and hay. These often contain seeds. When the horse digests its food, many of these seeds pass through undigested. This means fresh horse manure often contains weed seeds.
If you put fresh manure in your garden, you are planting weed seeds. This will lead to more weeding work later. This is a big problem with weeds in horse manure that is not properly processed.
Possible Pathogens
Fresh manure can sometimes have harmful bacteria. These can include things like E. coli. While less common in manure from horses used for pleasure riding compared to farm animals, it’s still a risk, especially if you plan to grow food crops.
Composting or aging manure helps kill these harmful bacteria. It makes the manure safer to use around food plants.
Salt Build-up
In some cases, horse manure can contain salts. This depends on what the horse eats and drinks. Too much salt in the soil can harm plant growth. Aging or composting helps to reduce the salt concentration, or at least makes it less likely to cause problems when mixed well into the soil.
The Magic of Aging and Composting
So, fresh manure has problems. The solution is simple: wait. You need to let the manure break down. There are two main ways to do this: aging or composting. Composting is better for killing seeds and pathogens.
Comprehending Aged Horse Manure
Aging manure means letting it sit in a pile. You just leave it alone for several months. During this time, it starts to break down. The strong nitrogen gets less harmful. The heat goes away.
Think of it like letting something mellow. It becomes less intense. Aged horse manure is safer to use than fresh manure. The pile should sit for at least six months, maybe even a year. It should look different. It will be darker. It will smell less strong.
However, aging alone does not always kill all weed seeds or harmful bacteria. Some seeds are tough. They can survive just sitting in a pile.
Grasping Composted Horse Manure
Composting is a more active process. It involves building a pile of manure and other organic materials. You add things like straw (often already mixed with the manure), leaves, and grass clippings. You need to add water and turn the pile.
Turning the pile brings in air. Microbes need air to work. As the microbes break down the material, they create heat. A well-managed compost pile gets very hot inside. This heat is important. It kills most weed seeds and harmful bacteria.
Composting takes less time than just aging, especially if you manage the pile well. It can take a few months to a year, depending on how you do it. The result is dark, crumbly stuff. It smells like good earth. This is composted horse manure. It is the best form of horse manure to use in your garden. How to compost horse manure properly involves getting the right mix of materials, moisture, and air.
How to Compost Horse Manure
Composting is the best way to make horse manure ready for the garden. Here are the steps:
Getting the Right Stuff
You will have horse manure. This usually includes bedding like straw or wood shavings. This is good! You need a mix of green (nitrogen-rich) and brown (carbon-rich) materials. Manure is mostly green. Bedding like straw or shavings is brown.
Aim for a mix. A common rule is about two parts brown stuff to one part green stuff. Horse manure with bedding often comes close to this mix naturally. You can add more brown stuff like dry leaves, shredded paper, or cardboard if needed.
Picking a Spot
Choose a spot for your compost pile. It should be easy to get to. It should have some space around it for turning. It is good to have it on bare ground so helpful worms and microbes can get in.
Building the Pile
You can make a simple pile. Or you can build a bin or use a composter. A bin keeps the pile tidy.
Start layering your materials. Or just mix them together. Make the pile big enough to hold heat, but not so big it is hard to turn. A pile at least 3 feet wide, 3 feet deep, and 3 feet tall is a good size.
Adding Water
Compost microbes need water to work. The pile should be moist, like a wrung-out sponge. Not too wet and not too dry. If it looks dry, add water. Especially add water when you turn it.
Turning the Pile
This is a key step in how to compost horse manure well. Turning adds air. It also moves material from the cooler outside to the hot inside. This helps the whole pile compost evenly.
Turn the pile every few weeks. If you want it to compost faster, turn it more often, like once a week. Be careful of the heat inside! You can use a compost thermometer to check the temperature. A hot pile reaches 130-160 degrees Fahrenheit. This heat kills weed seeds and bad bugs.
Knowing When It’s Ready
Compost is ready when it looks dark and crumbly. It should smell earthy, not like manure. You should not be able to tell what the original stuff was, mostly. This usually takes several months, maybe 3 to 12 months, depending on how much you turn it and the conditions.
Using composted horse manure means you have gone through this process. It is safer and more beneficial than fresh manure.
Nutrients in Horse Manure
What exactly does horse manure add to your soil? It has nutrients. These are the building blocks plants need. The main nutrients are nitrogen (N), phosphorus (P), and potassium (K). These are often shown as N-P-K numbers on fertilizer bags.
Manures are usually lower in these numbers than chemical fertilizers. But they also add organic matter and other good things. The exact nutrients in horse manure can change. It depends on what the horse ate, how old the manure is, and how it was stored.
Main Plant Foods (N-P-K)
- Nitrogen (N): Helps plants grow leaves and stems. It’s good for green, leafy growth. Fresh manure has a lot of nitrogen, but it can burn plants. Composted manure has less nitrogen, but it is in a form plants can use well. Nitrogen levels might be around 0.5% to 1.5% in composted manure.
- Phosphorus (P): Important for roots, flowers, and fruits. Helps plants store and use energy. Phosphorus levels might be around 0.2% to 0.5%.
- Potassium (K): Helps plants stay healthy overall. It helps them fight disease and handle stress. Potassium levels might be around 0.5% to 1.0%.
These numbers seem low compared to chemical fertilizers with numbers like 10-10-10. But remember, manure also adds organic matter. This makes the soil better in ways that numbers don’t show. Also, manure releases nutrients slowly. This means less is wasted.
Other Goodies
Horse manure also has other nutrients plants need in smaller amounts. These include calcium, magnesium, sulfur, zinc, copper, and iron. These micronutrients are vital for plant health, even if needed in tiny amounts.
Adding composted horse manure adds these nutrients and improves the soil structure. This is why using horse manure as fertilizer is a great natural choice.
Applying Horse Manure to Soil
Once your horse manure is well-aged or, best of all, composted, it is ready to use. How you apply it matters. You do not want to apply too much at once.
Mixing It In
The best way is to mix the composted manure into the top few inches of soil. You can do this before planting. Spread a layer about 1 to 3 inches thick over the garden bed. Then, use a shovel or tiller to mix it into the top 6 inches of soil.
Do this in the fall or early spring before you plant. This gives it a little more time to settle and mix with the soil before roots start growing actively. Applying horse manure to soil this way helps roots access the nutrients and benefits the whole soil layer.
Top Dressing
You can also use fully composted manure as a top dressing. This means spreading a thin layer on top of the soil around existing plants. Keep it a few inches away from the stems of the plants. Water it in well.
This works like a mulch. It helps keep the soil moist. As it breaks down more, it slowly feeds the plants. This is good for established plants, like bushes or trees. It can also work for vegetables during the growing season.
Making Compost Tea
Another way to use composted horse manure is to make “compost tea.” This is a liquid fertilizer. You soak composted manure in water for a few days. Then you use the liquid to water your plants.
This gives plants a quick nutrient boost. Strain out the solids before using the liquid. You can put the solids back in your compost pile or mix them into the soil.
Horse Manure vs Cow Manure
People often ask about different kinds of manure. Is horse manure better than cow manure? Or vice versa? Both are good for gardens, but they have some differences. Knowing these differences helps you choose.
Comparing Nutrient Levels
Generally, horse manure is considered a “hotter” manure when fresh. This means it starts with more nitrogen. Cow manure, especially from dairy cows, often has more moisture and is less “hot” when fresh. This is because cows digest their food more completely than horses.
Look at typical nutrient ranges:
| Manure Type | Nitrogen (N) | Phosphorus (P) | Potassium (K) |
|---|---|---|---|
| Fresh Horse | 0.5 – 1.5% | 0.3 – 0.5% | 0.5 – 1.0% |
| Fresh Cow | 0.2 – 0.6% | 0.1 – 0.3% | 0.1 – 0.5% |
| Composted Horse | 0.5 – 1.5% | 0.2 – 0.5% | 0.5 – 1.0% |
| Composted Cow | 0.5 – 1.5% | 0.2 – 0.5% | 0.3 – 1.0% |
Note: These numbers are averages. Real numbers can vary a lot.
Fresh horse manure starts with more nitrogen than fresh cow manure. But after composting, their nutrient levels become more similar. Both composted forms are excellent soil builders.
Structure and Texture
Horse manure with bedding (like straw) often has a looser, more fibrous texture. This helps add structure and air to the soil. Cow manure, being wetter, can be denser and heavier.
When composted, both break down into dark, crumbly material. Composted horse manure tends to remain slightly chunkier if coarse bedding like wood shavings was used, which can still be good for soil structure.
Weed Seeds and Digestion
Horses do not digest seeds as well as cows. This means fresh horse manure is more likely to contain viable weed seeds compared to fresh cow manure. This is why composting is even more important for horse manure to handle the weeds in horse manure problem.
Cows have multiple stomachs and digest food more completely. This kills more seeds during the process.
Accessibility and Cost
Availability depends on where you live. If you are near horse stables, horse manure might be easy and cheap, perhaps even free. If you are near cattle farms, cow manure might be more available.
In short, both composted horse manure vs cow manure are great. They offer similar benefits once broken down. The best choice might just be the one that is easier for you to get and compost properly.
Grasping Safety with Horse Manure
Using horse manure is generally safe for gardening, especially when composted. But a few things are good to know.
Herbicides in Manure
Sometimes, the hay or grass fed to horses might have been sprayed with certain weed killers (herbicides). Some of these chemicals can pass through the horse and remain in the manure. They are often not broken down by normal composting temperatures.
These specific herbicides (often called persistent herbicides) can hurt garden plants, especially vegetables like tomatoes, beans, peas, and potatoes. They can cause strange growth, curled leaves, or prevent plants from growing properly.
It is hard to know if manure contains these. Asking the stable owner if they use weed killers on their pastures or hay is a good idea. If they do, you might want to get manure from somewhere else.
You can also do a test. Plant some sensitive seeds (like peas or beans) in a small pot using the composted manure mixed with soil. Plant the same seeds in another pot with just regular soil. If the seeds in the manure pot grow strangely, the manure might have herbicide issues.
Handling Fresh Manure
Avoid touching fresh manure with bare hands. Always use gloves. This helps prevent contact with any potential bacteria. Wash your hands well after handling any manure or compost.
Storage
Store fresh manure away from water sources, like wells or streams. Piles of fresh manure can create runoff when it rains. This runoff can carry nutrients and bacteria into water, which is bad for the environment. Proper composting helps contain these issues.
Interpreting the Readiness of Composted Manure
How do you know for sure that your composted horse manure is ready to use? It is important to wait long enough.
What It Should Look Like
Ready composted manure should look like dark, rich soil. It should be crumbly, not clumpy or sticky. You should not see recognizable pieces of straw or manure.
What It Should Smell Like
It should smell like earth or finished compost. It should not smell like ammonia or fresh manure. A bad smell means it is not done breaking down or it needs more air (turning).
The Temperature Test
If you have been actively composting, the temperature inside the pile is a good sign. A pile that reached 130-160 degrees Fahrenheit and has now cooled down, staying at air temperature for a while, is likely finished. This heat helps kill problem stuff. If the pile is still hot, it is not ready.
Time
Even if you are not actively composting and just aging manure, time is your friend. At least six months is needed for aging. A year is better. Composting can be faster if managed well (turning, water, heat). Aim for a year if you are just piling it up without turning.
Using fully composted or well-aged manure avoids the issues of hot manure in garden beds and reduces weeds in horse manure piles significantly.
Practical Steps for Using Composted Horse Manure
Once you have your finished composted horse manure, here is how to put it to work:
Preparing New Beds
If you are starting a new garden bed, spread a layer of composted manure 2-4 inches thick over the area. Mix it into the top 6-8 inches of soil using a fork, shovel, or tiller. This is a great way to build rich, healthy soil from the start.
Boosting Existing Beds
Each year, add composted manure to your existing garden beds. A layer of 1-2 inches spread over the surface is usually enough. Mix it gently into the top few inches. Do this in the fall after the growing season is over or in early spring before planting.
Feeding Individual Plants
For plants that need a lot of food, like corn, squash, or tomatoes, you can mix a little extra composted manure into the soil when you plant them. Dig a hole, mix a shovel full of compost into the soil you removed, and then plant into this mix.
Using in Pots
You can mix composted horse manure into potting soil mixes. Do not use too much. A mix of about 1 part composted manure to 3 or 4 parts potting soil or garden soil works well. Pure compost can be too rich or drain poorly in pots.
Making Mulch
Well-composted manure can be used as a mulch layer around plants. Spread a layer 1-2 inches thick. Keep it a little away from the base of the plant stems. This helps hold moisture, keeps weeds down, and feeds the soil slowly.
Applying horse manure to soil in these ways adds valuable organic matter and nutrients, helping your garden thrive.
Frequently Asked Questions (FAQ)
Can I use fresh horse manure directly on my garden?
No, using fresh or “hot” horse manure directly can harm your plants. It has high nitrogen levels that can burn roots and contains weed seeds and potential pathogens. It needs to be aged or composted first.
How long does horse manure need to be aged or composted?
Aging takes at least 6-12 months. Composting can be faster, potentially 3-6 months, if managed well (turned regularly, kept moist, reaches hot temperatures). It is ready when it looks and smells like soil.
Does horse manure attract flies or pests?
Fresh manure can attract flies. Proper composting helps break down the material quickly and reduces odors, which makes it less attractive to pests. Storing fresh manure piles away from your main living areas is wise.
Is horse manure good for all types of plants?
Composted horse manure is good for most garden plants. It is especially helpful for vegetables, fruits, and flowering plants that need good soil and steady nutrients. Avoid using large amounts of fresh manure on sensitive plants or young seedlings.
Will horse manure make my garden smell bad?
Fresh manure has a strong smell. Well-composted manure should have an earthy smell, similar to good soil. If your composted manure smells bad (like ammonia or rot), it is not finished composting or needs more air.
What are the key nutrients in horse manure?
The main nutrients are nitrogen (N), phosphorus (P), and potassium (K). It also contains important micronutrients like calcium, magnesium, and sulfur. The exact levels vary.
How much composted horse manure should I add to my garden?
For new beds, mix in a layer 2-4 inches deep. For existing beds, add 1-2 inches each year and mix into the top soil.
Can I get diseases from using horse manure?
Fresh manure can potentially contain harmful bacteria. Proper composting kills most pathogens through heat. Always wear gloves when handling manure and wash your hands afterward, especially before eating.
What is the difference between aged and composted manure?
Aging is letting manure sit and break down slowly. Composting is actively managing a pile with other materials, water, and turning to create heat, which speeds breakdown and kills weed seeds and pathogens more effectively.
Is there a risk of herbicides in horse manure?
Yes, this is a concern if the horses ate hay or grass treated with persistent herbicides. These chemicals can pass through the horse and harm garden plants even after composting. Ask your source about herbicide use or do a plant test if unsure.
Using composted horse manure is a fantastic way to recycle a resource and build healthy, fertile garden soil. Just remember to process it properly before adding it to your beds.