Can Pig Manure Be Used in Gardening?
If you’re doing research on fertilizers for your garden and you’re looking for something more natural and organic, manure might come to mind. There are dangers of pig manure, though animal manures are rich in the three nutrients plants need the most: nitrogen (N), phosphorous (P) and potassium (K), says Organic Fertilizer Machine. It might seem ideal in that you’re recycling a waste product into something helpful, but there are factors to consider in order to use this material safely.
Pig manure can be used for some gardens, though compost and manure from herbivores is better. Pig manure should never be used for food-producing gardens.
Manure vs. Compost
Manure contains a good amount of organic matter that helps to structure and condition the soil for better growth. Increasing the amount of organic matter in soil improves drainage and water capacity, improves soil structure and provides nutrients for organisms that help the soil. It does have some drawbacks, however.
The first problem with pig manure is that pigs eat a variety of things, and as such, their manure can contain salmonella, E. coli, worms and a number of other parasites that can make humans sick. In fact, explains Morning Chores, any manure coming from an omnivore animal, like dogs, cats or pigs, should never be applied directly to any plant producing fruits, vegetables or herbs that people will consume. Manure from herbivores, like sheep, cows, chickens and horses, is a much safer choice.
That being said, many farmers recommend that all manure be composted before being added to a vegetable or fruit garden to ensure it is safe from potential pathogens. Composting is the act of breaking down and decomposing organic materials to smaller pieces to the point where they stabilize as nutrient-rich matter. You can compost nearly all food scraps along with some natural wastes into a soillike material that’s great for gardens.
Feeding a Garden
Many manures and composts are used to feed all kinds of gardens, be it vegetables, flowers or even grasses. It’s important to note, however, that manures don’t come with the correct balance to feed a garden by itself. Most manures and composted manure products contain too much phosphorus when compared to the nitrogen load. This means if you fertilize a bed for proper nitrogen, the bed will have too much phosphorus.
If you try to fertilize to the proper phosphorus amount, you may need another source of nitrogen. While high phosphorus levels alone won’t necessarily harm your garden, the runoff can cause issues with local water systems, explains the University of New Hampshire Extension. If your natural soil is low in phosphorus, manure products are a good option; however, if your garden is high in phosphorus, you may want to look into other fertilization options.
With some manure-based fertilizers, levels of compounds like ammonia and high levels of some nutrients may actually burn your plants rather than feed them. Fertilizer burn happens when you overfertilize the soil, which can overload the plant itself, and fertilizers also contain salts that dehydrate your young plants. A fertilizer burn can ruin a young garden. Composting helps to reduce this risk, as most composts are mixed with other matter as they decompose.
Treating Dangers of Pig Manure
Because of the likely presence of parasites that can harm plants grown for consumption, some people recommend never using pig manure for an edible garden. For some people, it isn’t worth the risk. However, a hot compost can render the manure usable if it is used correctly. This is part of proper pig manure management.
Composting creates heat at the center of the pile as the discards and scraps start to break down into other materials. If a compost pile can reach a temperature of about 140 degrees Fahrenheit and sustain that temperature for several weeks, many of the dangerous pathogens will break down, says the University of Maine Cooperative Extension.
However, you have to make sure that all of the suspicious manure is exposed to these temperatures for a significant period of time by frequently turning the pile. Note that most home-built compost piles will not reach these temperatures, so you’ll have to buy or build something specifically designed to add heat into the compost pile and turn it regularly for a period of up to four months.
How to Use Manure
In most cases, as a general rule, manure or compost should be applied to the garden at least 120 days (four months) before you plan to harvest from the garden. This lets sharper components, like ammonia, begin to decompose into nitrogen and other nutrients more easily absorbed by the plants and helps to reduce the risk of contamination. After planting your garden, don’t add any new manure-related products to the soil.
Keep in mind that many people still recommend never using cat, dog or pig manure as a fertilizer. If your household contains any individuals who are exceptionally sensitive to foodborne illnesses, you will absolutely want to err on the side of caution. These high-risk populations include young children, pregnant women and individuals with chronic illnesses or autoimmune disorders. If any of your produce might encounter someone in one of these populations, it is best to use another option.
However, this does mean that you can use composted pig manure on plants not meant to grow consumables. Use it on bushes, flowers and even your lawn – any kind of ornamental plants that you won’t be eating. As long as it stays away from vegetables and fruit trees, pig manure products can be used to provide nutrients to your lawn.
Best Kinds of Manure
The Old Farmer’s Almanac offers recommendations for types of manure that are best suited to different kinds of plants. For vegetables, chicken, cow or horse manure is recommended. It can be applied either early in the spring or in the fall after harvest to decompose over the winter.
For flowers, cow and horse manure are the most popular and are applied in early spring. For root crops, like potatoes, chicken, cow or horse manure is ideal and is applied either in fall or spring. Acid-loving plants will benefit from cow or horse manure that is applied only in early fall.
Are you considering pig manure vs. cow manure? Remember that pig manure isn’t recommended for any of these uses because manure from herbivore animals, like cows, is naturally safer for use. Unless you have a free or cheap source of pig manure or compost that you can be sure is safe, you may want to put your money into another kind of manure-based material or look into other fertilizers that will meet the needs of your specific soil.
Composting Pig Manure
If you do have a local source of pig manure or if you own pigs, it is possible to create a compost solution that will allow you to use the waste in a manner that benefits your yard even if you don’t use it on vegetables.
Aim for compost piles designed to help the contents reach higher temperatures. As a target, 140 degrees Fahrenheit as a continuous temperature will help weed out parasites, and temperatures above 145 degrees can help kill weed seeds that may have made their way through the animal and into the manure to be composted.
Some places recommend maintaining a temperature over 150 degrees for a long period of time. This is the other key point to consider: A longer period of composting will only produce a better product. Construct your compost solution with an eye to a period of months and up to a year to get the best yield.
- The Old Farmer's Almanac: Manure Guide
- Organic Fertilizer Machine: How to Compost Pig Manure into Organic Fertiliser
- Morning Chores: Pig Manure Compost: The Benefits, Risks, and How to Compost Pig Manure
- University of Main Cooperative Extension: Bulletin #2510, Guidelines for Using Manure on Vegetable Gardens
- University of New Hampshire Extension: Guidelines for Using Animal Manures and Manure-Based Composts in the Garden [fact sheet]
Danielle Smyth is a writer and content marketer from upstate New York. She holds a Master of Science in Publishing from Pace University. She owns her own content marketing agency, Wordsmyth Creative Content Marketing, and she enjoys writing home and DIY articles and blogs for clients in a variety of related industries. She also runs her own lifestyle blog, Sweet Frivolity.