Using fresh manure as a garden amendment can provide a wealth of nutrients to plants, but it comes with significant drawbacks and potential risks that gardeners must understand. Fresh manure, whether from cows, horses, chickens, or other animals, is rich in nitrogen, phosphorus, and potassium, but its high nutrient concentration can lead to “burning” plants, causing yellowing, wilting, or even plant death due to excessive ammonia content. Fresh manure can also disrupt soil pH balance and introduce high levels of salts, which can harm plant roots and inhibit water uptake.
Keep in mind that some manure may contain weed seeds that germinate in the garden, leading to increased weeding and competition with cultivated plants. A critical health concern is the potential presence of pathogens, such as Escherichia coli (E. coli), Salmonella, Listeria, and parasites like roundworms, which can contaminate fruits and vegetables, especially those consumed raw. This risk is heightened if manure comes into direct contact with edible crops.
Another issue is the presence of antibiotic residues or heavy metals in manure, particularly from intensively farmed livestock, which can accumulate in the soil and enter the food chain over time. Additionally, fresh manure can produce an unpleasant odor and attract pests like flies, rodents, or other animals. To mitigate these risks, gardeners should compost manure thoroughly before use. Composting at high temperatures (above 131°F or 55°C) for a sustained period can kill most harmful pathogens and weed seeds, rendering the manure safer and more beneficial for plants.
Proper timing of manure application is also crucial; applying it in the fall allows time for it to break down and minimize risks by the growing season, whereas using fresh manure during the active growing season is not recommended, particularly for crops intended for immediate consumption. By understanding these cons and following best practices, gardeners can safely incorporate manure into their gardens while protecting both plant health and human safety.
Fresh Manure Concerns:
Nutrient Burn: Fresh manure is high in nitrogen. When it breaks down rapidly in the soil, it releases a concentrated amount that can burn roots and harm plants. This is especially true with manure from herbivores like horses, rabbits, and chickens. Worm Castings, on the other hand, are a more mature and stable form of organic matter with a balanced nutrient profile.
Pathogens: Manure can harbor harmful bacteria like E. coli that can contaminate vegetables, especially those with fruits or leaves that come in contact with the soil.
Alpaca Manure's Advantages:
Lower Nitrogen Content: Compared to other herbivores, alpaca manure naturally has a lower nitrogen content. This reduces the risk of burning plants.
Fast-Composting: Alpaca manure tends to decompose quicker than some other types. This allows the nitrogen to release more gradually and become usable by plants.
General Safe Use of Fresh Manure:
Apply in Advance: If you want to use fresh manure, incorporate it into the soil well before planting, ideally in the fall for a spring planting. This allows time for decomposition and reduces the risk of burn or contamination.
Composting is Best: For most manure types, including alpaca, composting is the safest and most beneficial way to use it in your garden. Composting breaks down the manure, reduces pathogens, and creates a nutrient-rich soil amendment.
Manure in the Garden: Fresh or Forgotten?
Gardeners have long known the value of manure as a natural fertilizer. Packed with nutrients, it improves soil quality and feeds your plants. But there's a catch: fresh manure isn't always a friend. In fact, it can be downright deadly!
The Trouble with Fresh Manure:
The main culprit in fresh manure is nitrogen. While nitrogen is essential for plant growth, fresh manure has way too much of a good thing. As the manure decomposes rapidly in the soil, it releases a concentrated burst of nitrogen. This sudden spike can overwhelm young plants, burning their roots and essentially cooking them from the inside out.
Animals to Avoid (For Fresh Use):
Horses: Horse manure is particularly notorious for its high nitrogen content.
Rabbits: Similar to horse manure, rabbit manure packs a punch with nitrogen.
Chickens: Chicken manure can be quite hot, although some gardeners use aged chicken manure with success (see below).
Fresh Manure Done Right (Kind Of):
There are a couple of exceptions to the fresh-manure-is-bad rule:
Alpacas: Alpaca manure naturally has a lower nitrogen content, making it less likely to burn plants. However, it's still recommended to compost alpaca manure for best results.
Composting is King:
Composting is the hero of the manure story. The composting process breaks down the manure, reducing the risk of burning plants and eliminating harmful pathogens that might be present. Composted manure releases nutrients slowly, feeding your plants over time.
How Long Does Composting Take?
Composting time depends on various factors like pile size, moisture content, and temperature. A hot compost pile can break down manure in as little as a month, while a cooler pile might take several months. The best way to tell if your compost is ready is by its appearance and smell. Finished compost should be dark and crumbly with an earthy odor.
Types of Manure
Rabbit manure is a gardener's secret weapon, but unlike some fresh manures, it can be used directly in the garden with a little caution. While rich in nutrients like nitrogen, phosphorus, and potassium, fresh rabbit manure is less concentrated than other herbivores, reducing the risk of burning plants. However, to ensure safety, it's best to age the manure for a few weeks or simply mix it directly into the soil before planting. This allows the breakdown to happen gradually, releasing nutrients over time and avoiding any potential harm to your precious plants.
Horse manure, a readily available but powerful fertilizer, requires patience in the garden. Due to its high nitrogen content, fresh horse manure can be incredibly damaging to plants, essentially burning their roots. To safely utilize this nutrient powerhouse, composting is key. Composting allows the manure to break down slowly, reducing the concentrated nitrogen and transforming it into a safe and gradual food source for your plants. Aim to compost horse manure for at least several months, or until it becomes dark, crumbly, and has an earthy odor. This ensures your prized plants receive a steady stream of nutrients without the risk of a fiery demise from fresh manure.
Chicken manure is a double-edged sword in the garden. Packed with nitrogen, phosphorus, and potassium, it's a fantastic fertilizer for hungry plants. However, its strength lies in its weakness. Fresh chicken manure is very high in nitrogen, and similar to horse manure, can burn plant roots if used directly. To avoid this fiery fate for your plants, there are two options: composting or careful aging. Composting breaks down the manure, reducing the concentrated nitrogen and creating a safe, slow-release fertilizer. Alternatively, you can age fresh manure for several months in a well-ventilated pile. This allows some breakdown to occur naturally, making it less risky to use directly in the garden. Remember, with chicken manure, a little patience goes a long way in ensuring your plants reap the benefits without the burn.
Cow manure is a well-rounded fertilizer option for the garden, offering a good balance of nutrients compared to its horse manure counterpart. While both are rich in nitrogen, cow manure generally has a lower concentration, making it less likely to burn plants. This advantage can be attributed in part to the cow's digestive system. With four stomachs, cows thoroughly break down their food, which reduces the amount of readily available nitrogen in the manure. Additionally, cow manure boasts a more balanced profile of phosphorus and potassium, making it suitable for a wider variety of plants. Another benefit of cow manure is its weed seed control. The cow's complex digestive system effectively destroys most weed seeds, reducing the risk of unwanted hitchhikers sprouting in your garden beds. This advantage is less prevalent with horse manure, which may contain viable weed seeds that can germinate after being spread. So, when it comes to cow manure vs. horse manure, the cow wins for its gentler nitrogen release, broader nutrient profile, and superior weed seed control.
Alpaca manure. Unlike its high-nitrogen cousins like horse manure, alpaca manure is a gardener's delight. While still containing valuable nutrients, alpaca manure boasts a naturally lower nitrogen content. This difference stems from their unique digestive system. Alpacas, like cows, are ruminants with multiple stomachs, allowing for thorough digestion and reducing the amount of readily available nitrogen in their manure. This low nitrogen content makes fresh alpaca manure a safer option for direct use in the garden, although composting is always recommended for maximum benefit. However, similar to cows, alpacas' multiple stomachs aren't as effective at destroying weed seeds as the intense heat generated in a hot compost pile. Therefore, to ensure weed-free beds, it's best to compost alpaca manure or use other weed control methods alongside it. In comparison to horse manure, alpaca manure offers a gentler approach to fertilization with less risk of burning plants and the added bonus of being practically odorless.
Bat manure, also known as guano, is a fertilizer in the gardening world. Bat guano is a popular organic fertilizer due to its high nutrient content, but its use comes with potential risks that gardeners should consider. One primary concern is the possibility of disease transmission. Bat guano can harbor fungal spores that cause histoplasmosis, a respiratory disease that can be severe, particularly in immunocompromised individuals. Additionally, improperly handled or aged guano may contribute to soil imbalances, such as excessive nitrogen or phosphorus, which can harm plants and pollute nearby water sources through runoff. Another concern is the ethical and environmental impact of guano harvesting, which can disrupt bat habitats and colonies. Regarding bird flu, though bat guano is not directly linked to avian influenza, gardeners using bird guano should be cautious, as it may contain pathogens like Salmonella or Escherichia coli, which can pose health risks. Gardeners should wear protective gear, such as gloves and masks, when handling guano, ensure it is thoroughly composted to kill harmful pathogens, and avoid inhaling airborne particles. Additionally, over-reliance on guano as a single nutrient source can lead to nutrient imbalances in the soil, so it is best used as part of a broader soil management strategy.
Unlike horse manure, which packs a nitrogen punch that can scorch plants, bat guano boasts a rich and balanced blend of nutrients including nitrogen, phosphorus, and potassium. This ideal combination makes it a fantastic all-around fertilizer for many plants. However, similar to alpacas and cows, bats don't have multiple stomachs for intense digestion. Therefore, bat guano may still contain viable weed seeds. Composting guano can help reduce some weed seed viability, but it's not a guaranteed solution. The term "guano" comes from the Quechua word "wanu," which translates to "dung" referencing droppings of various animals. Indigenous cultures in the Andes recognized the fertilizing power of guano long before it became a global commodity. So, when it comes to bat guano versus horse manure, guano wins for its balanced nutrient profile, making it a gentler and more complete plant food option.
Using bat guano in cannabis cultivation has gained popularity for its natural nutrient profile, but it poses serious health risks that can sometimes lead to fatalities. Bat guano, particularly when fresh or improperly handled, can harbor fungal spores of Histoplasma capsulatum, which cause histoplasmosis—a potentially fatal respiratory disease. Cannabis growers who disturb dried guano in enclosed spaces, such as greenhouses or indoor grow rooms, risk inhaling these spores. The confined conditions often exacerbate the concentration of airborne particles, increasing the likelihood of infection. Symptoms of histoplasmosis can range from mild flu-like effects to severe respiratory distress and organ damage, especially in immunocompromised individuals. Reports of deaths linked to histoplasmosis outbreaks among growers underscore the dangers of inadequate protective measures when handling bat guano. Beyond disease, the use of guano in indoor grows may release ammonia and other volatile compounds that contribute to poor air quality, posing additional risks to workers. Growers are urged to use fully composted guano, ensure adequate ventilation, and wear protective equipment, including respirators, to mitigate these risks. Educating growers on these hazards is critical to preventing further tragedies while encouraging safer, more sustainable cultivation practices.
Goat and sheep manure are gardeners' gems, offering a gentler alternative to high-nitrogen options like horse manure. Similar to cow manure, goats and sheep have four-part stomachs that break down their food extensively. This process reduces the readily available nitrogen content in their manure, making it less likely to burn plants. This lower nitrogen content also allows you to use fresh goat or sheep manure in a pinch, although composting is always recommended to maximize nutrient availability and eliminate pathogens.Another benefit shared with cow manure is weed seed control. The multiple stomach digestion system of these ruminants is somewhat effective at destroying weed seeds, but composting remains the most reliable method for ensuring a weed-free garden bed. Compared to horse manure, goat and sheep manure provide a more balanced nutrient profile and a lower risk of scorching plants. They're also generally easier to handle due to their pelletized form. So, when it comes to horse manure versus goat or sheep manure, the latter wins for its gentler approach to fertilization and its convenience.
Bison manure, also known as buffalo manure, is another champion in the world of natural fertilizers. Like its distant cousin the cow, the bison boasts a four-chambered stomach that facilitates thorough digestion. This digestive process reduces the readily available nitrogen content in their manure, making it a safer option compared to the scorching potential of horse manure. This lower nitrogen content allows for some flexibility – you can use fresh bison manure in a pinch, but composting remains the best practice to unlock all its nutritional benefits and eliminate pathogens.
Similar to cows and other ruminants, bison digestion offers some degree of weed seed control. However, composting is still the most reliable method for ensuring a weed-free garden. Where bison manure truly shines is its microbial diversity. Bison graze on a wider variety of plants than cows, leading to a richer and more diverse microbial community in their manure. This translates to potential benefits for soil health and plant growth beyond just basic nutrients. Overall, compared to horse manure, bison manure offers a gentler approach to fertilization with a lower risk of burning plants, and boasts the added advantage of a potentially more beneficial microbial profile for your garden.
As for composting your kid's diapers, the answer remains a firm no. Human waste contains pathogens that require specific high-heat composting techniques not achievable in a typical backyard setup. Stick to safer alternatives like animal manure (bison!), food scraps, or commercially available organic fertilizers for a happy and healthy garden.
Worm Castings: Nature's Black Gold for Your Garden. Worm castings, also known as vermicompost, are a nutrient-rich organic fertilizer produced by earthworms. But how exactly do these wiggly creatures turn organic matter into gardening gold? Earthworms consume organic matter like leaves, food scraps, and compost in their muscular gizzards. As this organic matter passes through their digestive system, nutrients are extracted and microbes are introduced. The remaining material is then excreted as castings, a granular and odorless substance. Manure vs. Castings: Not Quite the Same. While both come from animals, worm castings differ from manure in a few key ways. Manure can be high in nitrogen, which can burn plants if not composted properly. Castings, on the other hand, are a more mature and stable form of organic matter with a balanced nutrient profile. The Advantages of Black Gold. Gardeners love worm castings for a multitude of reasons: Nutrient Rich: Castings contain a plethora of macro and micronutrients essential for plant growth, including nitrogen, phosphorus, potassium, calcium, and magnesium. Improved Soil Structure: The castings' granular form helps aerate the soil, allowing for better root development, drainage, and water retention. Microbe Powerhouse: The digestive process introduces beneficial microbes into the castings, which can help suppress plant diseases and promote overall soil health. Safe for Seedlings: Unlike manure, castings are gentle enough for use with delicate seedlings and around young plants. Organic Advantage: Worm castings are a completely natural and organic way to fertilize your plants, making them ideal for organic gardening. Not All Castings Are Created Equal! While the core benefits remain the same, the specific nutrient content of castings can vary slightly depending on the type of worm and the organic matter they consume. However, these differences are usually minor and all types of worm castings offer significant benefits for your garden. Overall, worm castings are a valuable addition to any gardener's toolkit. By harnessing the natural power of earthworms, you can create a thriving and healthy garden for your plants.
Human poop, like horse manure, contains valuable nutrients for plants, it's generally not recommended for use in home gardens. Here's why:
Pathogen Risk: Human waste can harbor harmful bacteria, viruses, and parasites that can contaminate vegetables and pose a health risk. Unlike a cow's multiple stomachs which break down pathogens, human digestion doesn't eliminate these entirely.
Regulations: Many areas have regulations regarding human waste disposal, and using it in your garden might violate local codes.
Composting Considerations: Composting human waste requires specific techniques and high temperatures to effectively eliminate pathogens. Composting toilets designed for this purpose exist, but they're not a common household solution. Composting diapered waste is definitely not recommended due to the high concentration of pathogens in infant feces. There are safer and more regulated options for fertilizing your garden. Consider composted animal manure (cow, alpaca), composted food scraps, or commercially available organic fertilizers. While horse manure requires composting due to its high nitrogen content, human waste presents a greater health risk and isn't suitable for most home gardens. Stick to safer alternatives for a thriving and healthy garden.
Fresh vs. Composted: The Takeaway:
For most manure types, composting is the way to go. It's a safe and effective way to turn manure into a valuable soil amendment. If you're impatient and have access to alpaca manure, you might be able to get away with using it fresh, but proceed with caution and incorporate it well before planting. Otherwise, let your compost pile work its magic and enjoy the long-term benefits of composted manure in your garden!
Always Remember:
Check with your local gardening resources for specific recommendations on using manure in your area.
If unsure, it's always better to err on the side of caution and compost your manure first.
GroEat Farm, LLC is a small, sustainable family farm located in Bozeman, Montana. We’re located in the beautiful Hyalite foothills, below the Gallatin Mountain Range. The hardneck varieties that grow at our farm (Ophioscorodon) flourish here, due to the combination of the cold winters, temperate summers, moist spring, and the dynamic alluvial soils, washed down from the Gallatin Range (comprised of Archean metamorphics, Paleozoic and Mesozoic sedimentary rocks, and Eocene volcanics). Not only are the GroEat Hardneck garlic healthy and beautiful, the flavor’s are robust and delicate.
Our mission at GroEat Farm, LLC is to grow premium hardneck garlic, preserve garlic varieties for the future (through propagation), and to provide others with the opportunity to grow garlic from our seed. We help home gardeners, chefs, small-scale commercial growers, gardeners, plant nurseries, and anyone else looking for better hardneck garlic. We are continuing a very long tradition of growing quality gourmet and seed hardneck garlic.
