Are the plants in your garden failing to flower? Do the leaves have dark discolorations along the outside? If so, your soil may have a phosphorus deficiency.

Fortunately, you can amend your soil by adding bone meal. Bone meal is an organic fertilizer that will help your plants develop roots, flowers, and fruits.

If you want to learn more about the benefits of bone meal, dig right into our comprehensive guide. We’ve got the answers to all of the most frequently asked questions about bone meal.

What is Bone Meal?

Bone meal fertilizer is an all-natural byproduct of ground animal bones. It is used as an organic fertilizer for plants. Bone meal contains an abundance of phosphorus, which is one of the three essential plant nutrients.

Phosphorus promotes everything from root development to flower growth. Without enough of it, plants appear stunted and malnourished.

Bone meal is an otherwise unused byproduct of animal slaughter. It undergoes a nutrient-releasing steaming process before being ground into fine and coarse powders. While often combined into premixed fertilizing solutions, bone meal is also sold on its own.

What Can Bone Meal be Used for in Gardening?

Bone meal is used as an organic soil amendment. It is commonly used to boost the level of phosphorus in soil. However, it can also be used to add other essential nutrients, including calcium and nitrogen.

Bone Meal for Phosphorus

Bone meal is mainly used as a source of phosphorus. Plants need phosphorus during nearly every stage of their development. Because of its density, it takes a long time for bone meal to release all of its phosphorus stores. As such, a single application of bone meal can last as long as four months.

Bone Meal for Calcium

Bone meal is also high in calcium. Calcium is considered a secondary plant nutrient.

It is required during the development of a plant’s cell walls. Calcium is also responsible for maintaining the salinity of the soil. Without an adequate amount of calcium, soils may be thrown off balance. Signs of calcium deficiency include stunted growth, shallow roots, growth abnormalities, and more.

With that said, a soil with a pH rating that is higher than seven may have an overabundance of calcium. Excess calcium can block plants from absorbing sufficient amounts of fundamental nutrients. This is yet another reason why soil testing is so important.

Bone Meal for Nitrogen

Some bone meal also contains small amounts of nitrogen. However, bone meal alone is not usually enough to amend nitrogen-deficient soil.

Instead, we recommend adding a nitrogen-rich composted manure. Bone meal and manure can be combined to create a highly beneficial organic fertilizer.

What are the Benefits of Using Bone Meal?

Bone meal can safely and adequately amend phosphorus-deficient in soil. Bone meals slow-release nutrients offer a safe and steady source of sustenance for plants.

While fast-working synthetic fertilizer can burn plants, bone meals effects are gentle and drawn-out.

Bone meal is not water-soluble. As such, it needs to decompose before it can release its nutrients.

It’s Green

Bone meal fertilizer is an otherwise unwanted and abundant agricultural byproduct. It is one of the most environmentally friendly fertilizers on the market.

It’s also available in organic forms, making it highly suitable for organic growers.

Not only that, but bone meal is also a biologically safe fertilizer. Unlike synthetic fertilizers, bone meal does not run a high risk of polluting waterways or harming animals.

It Improves Roots

The phosphorus in bone meal helps in the development of plant roots. Roots with sufficient access to phosphorus tend to be stronger and more developed.

Phosphorus-deficient roots are usually long and weak.

Phosphorus-rich plants also tend to feature wider root collars. As such, they are more capable of absorbing water, nutrients, and oxygen.

Many signs of phosphorus deficiency lurk under the surface of the earth, which is yet another reason you should have your soil tested every season.

Better Blooms

Phosphorus-deficient plants may not flower till late in the growing season. This can have a severe effect on the development of fruits, vegetables, and seeds.

With stronger roots and shoots, phosphorus-rich plants find it easier to transfer energy to flowers.

Better Color

Phosphorus-deficient leaves often have a blue or purple tint to them. What’s more, some of these nutrient-deficient plants will be yellow and frail.

Not only does bone meal improve the health of your plants, but it also makes them more vibrant and aesthetically pleasing.

Combines Well with Other Soil Amendments

There are few better soil amendments than organic manure or compost. However, these nitrogen-rich substances are often thrown off by synthetic fertilizers.

While bone meal is an incomplete fertilizer on its own, it’s the perfect pairing for compost.

What are Some Problems with Bone Meal?

You’re probably wondering if there are any downsides to bone meal. We’ve got this answer covered in the section below!


Bone meal is expensive. Ten pounds of bone meal, or enough to adequately amend a 100-square-foot garden, costs about $20. That doesn’t include the cost of a home soil test or other necessary soil amendments.

Not a Complete Fertilizer

It is important to remember that bone meal is not a complete fertilizer. It only offers substantial amounts of phosphorus. As such, you must utilize other plant amendments to alter the nitrogen and potassium levels in your soil.

It can Leach into Groundwater and Runoff

Phosphorus-rich soil has the potential to expel polluted runoff water. When phosphorus-rich water enters waterways, the waterways become highly susceptible to algae.

These plants deplete waterways of oxygen. As such, they often kill off fish and other water-borne creatures. What’s more, they make water unsafe for human activities.

To avoid harming waterways, follow your local fertilizer application recommendations.. Some regions recommend applying fertilizers at specific times.

Another good rule of thumb is to apply bone meal directly to your plants. If you spill it spread it, clean it up immediately.

Some Plants Don’t Need a Lot of Phosphorus

Not all plants thrive under the same phosphorus levels. For example, legumes and leafy vegetables actually prefer more nitrogen.

Excess Bone Meal Can Reduce Healthy Soil Fungi

It is essential to records about your bone meal treatments. Soil math needs to be exact!

Excess phosphorus can inhibit the growth of healthy fungi. These fungi help plants recover essential nutrients and water from the soil. They are also the only catalyst for microbial activity.

When Should You Use Bone Meal in the Garden?

You should always have your soil tested before adding bone meal. Home soil test kits are available at most lawn and garden centers. These kits provide immediate results, including the pH and nutrient levels.

Most soil test results will offer nutrient levels, noticeable deficiencies, and amendment recommendation.

You can also send your soil out for testing. Many agricultural extensions offer free and low-cost soil testing. You can find a state-by-state list of soil testing labs here.

Do not take soil samples unless the conditions are suitable. Soil that is too wet or dry may produce incorrect data.

What’s more, always test your soil in fall. While bone meal is added during the growing season, other amendments may need to be added in advance.

Plants need six essential nutrients to thrive. Bone meal is an adequate source of three of these nutrients, including phosphorus, calcium, and nitrogen.

How to Use Bone Meal in the Garden

If your soil test results show nutrient deficiencies, you can add bone meal directly to your soil. It’s super easy to do. In no time, you will see the benefits of this natural amendment.

Add Bone Meal Directly to Your Garden

We recommend adding 5 to 10 pounds of fertilizer per every 100 square feet of soil. The one meal will slowly release phosphorus and other nutrients over four months.

Another option is to sprinkle a small amount of bone meal directly into a hole before adding a plant. You may add 1 or 2 tablespoons of bone meal to each hole.

Most plant experts recommend working bone meal deep into the soil. We recommend mixing your bone meal into the first 3 inches of soil. This ensures that the roots have access to the slow-release nutrients during every stage of the growing process.

Add Bone Meal Directly to Your Compost Pile

You may also add bone meal directly to your compost pile. When amending compost, add the same amount of bone meal as you would if you were amending the soil.

Do this right before you incorporate your compost into your soil. Ensure that the compost is worked into the top 1 to 3 inches of soil.

Add Bone Meal During the Growing Season

You can apply a small amount of granular bone meal directly to the surface of the soil. It’s best to do this during a plant’s flowering stage because of bone meal’s lengthy decomposition time.

Apply Liquid Bone Meal

Liquid bone meal is a processed alternative to traditional granules and powders. Many gardeners believe that liquid bone meal breaks down and releases nutrients faster than solid bone meal.

You can use liquid bone meal throughout the entire growing season to promote healthy root, shoot, and fruit growth.

Mix your liquid bone meal with the required amount of water. Then, use a watering can or hose attachment to disperse it into your garden. This can be repeated daily or weekly, depending on the manufacturer’s recommendations.

Crop-Specific Applications

While all plants need phosphorus to thrive, some phosphorus-deficient crops are easier to pinpoint. For example, corn and lettuce typically develop purple stems when they aren’t getting enough of this essential nutrient. Other plants may fail to flower or grow.

Using Bone Meal on Flowers

Many gardeners add bone meal shortly after their plants start flowering. This helps to ensure that the flowers and any subsequent fruits or seeds reach full maturity.

How Bone Meal Acts in Soil

When bone meal is added to a soil, it starts to decay. During the decay process, phosphorus is released. The phosphorus attaches to the soil. After which, it is absorbed by the plants.

Precautions for Using Bone Meal

Most gardeners are hesitant about using new substances. Below, you’ll find ways to subside the most common bone meal concerns.

Mad Cow Disease Concerns

While gardeners have used bone meal for hundreds of years, many people wonder if it is harmful to their health or the environment. Many gardeners are especially concerned about bone meal derived from bovines.

According to the Organic Consumers Association, only a small percentage of bovines are tested for Mad Cow Disease. This brings about concerns that bone meal may contain the disease.

While these fears are reasonable, it’s worth noting that you can purchase bone meal that has been tested for Mad Cow Disease. What’s more, you can purchase a bone meal made specifically from hog bones.

If you’re still concerned about using bone meal, we recommend that you wear a mask and gloves when applying it to your garden. This will prevent you from inhaling any potentially harmful pathogens.

Use Fish Bone Meal Instead

If you are uncomfortable with the concept of animal-derived bone meal, fish-derived bone meal is a reliable alternative. Fish-derived bone meal has an average NPK of 3-16-0.

As such, it offers practically identical benefits to traditional bone meals. With that said, it breaks down faster than bovine-derived bone meals.

Of course, not all gardeners are willing to tolerate the unsurprisingly fishy smell of this type of fertilizer.

Some Brands are Inferior

Bone meal is also used as an animal feed. The variety given to animals contains over two-times the amount of phosphate. This rate of phosphate is not conducive to plant growth.

Bone meal sold as fertilizer has an average NPK rate of 3-15-0. However, numbers vary depending on the manufacturer.

Many lawn and garden centers stock vetted bone meal. Jobe’s, Espoma, Neptune’s Harvest, Down to Earth, and Dr. Earth are just some of the more popular bone meal brands available to consumers.

Can Be Harmful to Pets

While bone meal does not contain any chemicals, it can be harmful to cats and dogs. Unfortunately, pets often enjoy the taste of bone meal.

According to the pet poison helpline, bone meal has a mild to moderate toxicity. It can cause nausea, drooling, and other temporary discomforts. When large amounts of bone meal are consumed by an animal, a large, dense ball has the potential to form in their gastrointestinal tract.

Compatible pH Levels

According to Colorado State University researchers bone meal is not effective in soils that have a pH of 7 or more. If your soil has a pH above 7, you must amend it before adding bone meal.

How to Lower Your Soil’s pH

If your soil has a pH higher than seven, you have some work to do before you can add bone meal. Alkaline soil, or soil with a pH above seven, can benefit from peat moss, elemental sulfur, iron sulfate, or another acidifying fertilizer.

According to Iowa State University researchers, pH impacts the availability of plant nutrients. Most plants thrive in soil that has a 5.5 to 7 pH.

Use the results of your soil test to determine the exact amount of acidifying fertilizer to add to your soil. Many agricultural extensions offer amendment guides.

For example, Clemson University offers these guides for adding sulfur and aluminum sulfate. The guides allow you to easily calculate how much fertilizer you need to add to alter present pH to your desired pH.

Interpreting NPK Values

Have you ever noticed the three-number codes written on fertilizer bags? These are known as NPK values.

The N stands for nitrogen, the P stands for phosphorus, and the K stands for potassium. The numbers represent the ratio and concentration of these three essential plant nutrients. For example, a 10-10-10 fertilizer contains 10% of each of these three nutrients.

While bone meal contains a high concentration of phosphorus, it is still labeled with an NPK value. The N value typically ranges between one and three. Whereas, the P value is usually between 12 and 16. Finally, the K value is almost always zero.

With that said, a typical bone meal NPK has a value of 3-15-0 or 3-16-0.

Final Thoughts

Bone meal is a safe, natural soil amendment that can improve every aspect of your garden.

Farmers have been using it long before the production of synthetic fertilizers.

Have you recently used a bone meal fertilizer? Did it improve the quality of your plants?

Let us know about your experience using bone meal in the comment section below.

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