How To Fertilize With Bone Meal: The Complete Guide

Fertilizers come in a wide range of varieties, including inorganic and organic, and they play an essential role in supplying nutrients to the soil. Bone meal is a type of organic fertilizer that’s used to provide essential macro and micronutrients to your plants.

Here’s how to fertilize with bone meal:

  1. Mix it with manure and other nitrogen-heavy fertilizers.
  2. Only apply as much bone meal as necessary.
  3. Incorporate bone meal into the soil.
  4. Spread bone meal over the soil during the growing season.
  5. Add bone meal when repotting or planting seedlings.
  6. Ensure that the soil pH is at the ideal level.
  7. Use bone meal to combat deficiencies.
  8. Ensure fertilizer dispersal by powdering the bone meal.
  9. Use bone meal to fertilize root vegetables and bulbs.
  10. Apply bone meal to flowering and fruiting plants.

In this article, I’ll explore each of these tips in more detail, so you know exactly how to fertilize your plants with bone meal. Read on to learn more!

1. Mix It With Manure and Other Nitrogen-Heavy Fertilizers

Using manure, compost, and other organic fertilizers is an excellent way to fertilize your plants, whether indoors or outdoors.

However, organic fertilizers like manure or compost tend to have a higher proportion of nitrogen than the other macro and micronutrients that plants require. Nitrogen is one of the more heavily used nutrients, as plants need nitrogen for several activities that contribute to their overall growth.

Apart from nitrogen, plants need two other macronutrients, which are:

  • Phosphorus, used for root growth, and
  • Potassium, used by plants to support water intake.

Apart from these macronutrients, plants also need several micronutrients like calcium and magnesium. In most cases, the soil has enough micronutrients, but some, like calcium, tend to deplete quickly and need to be replenished.

Adding organic supplements that contain the other macro and micro plant nutrients is a great way of keeping plants healthy by supplying them with everything they need to grow.

Bone meal is an organic fertilizer, which means that it’s slow-release and can be easily mixed with other organic fertilizers that won’t burn your plants.

Bone meal has been an essential supplement in agriculture and gardening for decades because it’s an important source of macronutrients such as phosphorus and calcium. Mixing bone meal with compost or manure is a great way to build a complete fertilizer that supplies your plants with all the nutrients they need throughout the growing season. 

2. Only Apply As Much Bone Meal As Necessary

Bone meal is an organic fertilizer and breaks down slowly in the soil, which means that the possibility of fertilizer burn is low. However, adding too much bone meal can lead to the presence of excess phosphorus in the soil, which is detrimental to plant growth.

Phosphorus, commonly referred to as phosphate, is important for root growth. However, when there’s too much phosphate in the soil, root growth is affected adversely.

Plants in soil with too high phosphate levels grow shallow root systems, preventing them from absorbing nutrients from the deeper soil layers. High phosphate also results in thin roots that break easily, limiting the plant’s ability to uptake water and nutrients from the soil. As a result, high phosphorus levels impede plant growth and health.

Applying too much bone meal can also attract pests to your garden. The smell attracts rodents like rats, mice, and raccoons and larger animals like dogs.

The problem is further compounded if you’ve scattered the bone meal on the surface of the soil because the substance takes a while to break down. Excess bone meal sits on the surface of the ground for much longer than you’d think, releasing smells that attract all kinds of animals to your garden.

A good way to avoid excess phosphorus in the soil is to ensure that you get a soil assessment done every few years. The soil assessment will help determine exactly how much phosphate you need to add to your plants.

When applying a large amount of phosphate, incorporate it into the soil whenever possible to avoid attracting pests. Spreading the fertilizer on the surface is only recommended when you’re simply providing additional supplementation to your plants during their growing season.

3. Incorporate Bone Meal Into the Soil 

As discussed earlier, surface application of bone meal can attract animals and pests like rodents to your garden, especially if you need to apply a large amount of it as a soil amender.

Mixing a fertilizer like bone meal with the soil is advantageous for several reasons.

Bone meal isn’t water-soluble, so it takes a long time to break down. Incorporating it into the soil ensures that the nutrients are immediately available to the roots as and when they’re released.

Microbial activity plays an important role in the breakdown of bone meal to release nutrients like phosphorus and calcium in a form that plants can take up. This activity increases the number of microbes and other organisms in the soil, which improves soil quality over time.

Incorporating bone meal into the soil in the fall also improves soil quality and increases phosphorus and calcium levels in time for the growing season in spring. An improved soil quality means that you will be able to reduce your use of fertilizer over time, which is economically efficient.

Mixing bone meal in the soil also prevents run-off, which is a common cause of fertilizer pollution in water bodies, apart from being a waste of fertilizer.

4. Spread Bone Meal Over the Soil During the Growing Season

Spreading bone meals on the soil’s surface is a bad idea most of the year, but during the growing season, a surface broadcast of bone meal might become necessary.

The growing season is the time when there is sufficient light for plants to produce the nutrients they need from photosynthesis, which is usually in early spring.

At this time, plants come out of dormancy and start taking up large quantities of nutrients so they can grow their roots and stems. This is the best time to apply fertilizer, especially inorganic fertilizers, as plants need large amounts of phosphorus to grow their roots deep enough before they can grow upwards.

Even if you’ve incorporated phosphorus into the soil before, you’ll need to add more as the bone meal you’ve already added will be used up by the plants rapidly as they grow. At this time, surface applications are a great way of quickly supplying your plants with the nutrients they need.

Watering the soil thoroughly before you apply the bone meal will ensure that the fertilizer gets wet and is dispersed through the soil easily and taken up by the roots of the plants.

It’s very important that you only spread a thin layer of bone meal when you’re applying it on the surface. Too much bone meal will make it hard for all of it to be dispersed into the soil and the roots.

A lack of dispersal means that the nutrients will not be available to the plants when they need them. The excess bone meal will simply sit on the surface and attract pests like rodents and dogs to your garden.

You might need to apply bone meal several times during the growing season, depending on how fast your plants are growing. Multiple smaller applications ensure that you only supply your plants with as much phosphorus and calcium as and when needed.

5. Add Bone Meal When Repotting or Planting Seedlings

When repotting plants, you would typically avoid adding fertilizer for the first few weeks to give the plants time to recover from transplant shock. Seedlings are also treated the same way, with a delayed application of fertilizer, as this prevents fertilizer burn.

Newly repotted plants and seedlings both have fragile root systems that are easily overwhelmed by fertilizer. The mineral salts in inorganic fertilizers will build up outside the small roots and draw water out of the plant tissue, resulting in dehydration, yellow, and browning of leaves, which is known as fertilizer burn.

Starting fertilizers are sometimes used to support seedlings and newly repotted plants, as these solutions help supply a very diluted mixture of nutrients to help roots grow. However, you do need to be careful about the amount of starting solution you use, as well as its strength, to ensure that it doesn’t burn the leaves.

Another way to help plants with young roots like seedlings and repotted plants is to use slow-release fertilizers like organic fertilizers, which will not burn the roots at all. The nutrients are released slowly, and the plants are able to uptake as much as they need at a time.

Mixing manure or compost with the soil is a great way to support newly repotted plants as they grow out their roots. As these fertilizers are low in compost, incorporating bone meal will ensure that the plants get the phosphorus they need for root growth and development.

6. Ensure That the Soil pH Is at the Ideal Level 

Apart from microbial activity, soil pH plays an important role in the release of nutrients from fertilizers, especially slow-release fertilizers.

Organic slow-release fertilizers like manure, compost, and bone meal can be suspended in water or steeped in water, but they aren’t water-soluble, unlike most inorganic fertilizers. Microbial activity and changes in the soil temperature and pH levels are responsible for the release of nutrients from organic fertilizers, including bone meal.

Ideally, pH levels in your soil should be maintained under 7.0. A weakly acidic pH value is better for releasing phosphorus from bone meal and making the nutrient available for uptake from plants. The nutrient is most easily released from a bone meal when the pH is maintained between 6.5-6.6, though this level of precision is unnecessary.

A soil analysis will give you more information about your soil pH. Using sulfur and compost is the best way to amend your soil pH to make it more acidic and receptive to bone meal. However, you should only amend the soil pH depending on the needs of your plants.

Some plants like lavender and honeysuckle prefer more alkaline soils, and it is better to use another source of phosphorus for these plants instead of making the soil more acidic.

7. Use Bone Meal to Combat Deficiencies

As I’ve mentioned earlier, bone meal is an excellent source of phosphorus and calcium, both of which are essential plant nutrients.

Phosphorus is particularly important for plants because of its role in encouraging root growth. As one of the macronutrients, phosphorus is very quickly depleted from the soil, especially during the growing season.

In plants, a phosphorus deficiency is observed in the leaves. The color of the leaves becomes duller, with a blue-green tinge. Over time, as the deficiency worsens, the leaves start becoming paler. Often, the older leaves are affected first, then the younger leaves which start growing smaller and smaller as the deficiency increases.

As the deficiency progresses, plants respond by growing shallow root systems, which makes them easier to uproot in bad weather like heavy winds and rains. Plants also respond with reduced shoot growth, so even if your roots grow normally, the shoots will refuse to grow.

Calcium deficiencies are rare and harder to manage as calcium is a heavy element and moves slowly through plant tissue. This deficiency is more prevalent in acidic soils, which makes bone meal the perfect amendment, as nutrients from the bone meal are more easily released in soils with higher pH levels.

Symptoms of calcium deficiency include yellowing of leaves along the margins and dark veins in the leaves. Calcium deficiency affects the roots as well, with root tips becoming brittle and breaking off.

In cases of deficiency, it’s important to get the nutrients to the plant quickly. Broadcasting a thin layer of bone meal on the surface of the soil after watering thoroughly is the best method to disperse the fertilizer.

8. Ensure Fertilizer Dispersal by Powdering the Bone Meal

Bone meal, as the name itself suggests, is usually bone ground down. Powdering the bone meal into fine particles makes it easier to disperse into the soil and become utilized by the plants.

Powdered bone meal mixes well with soil, and even when it’s spread on the surface, it travels easily through the top layers down to the finer root hairs of the plant. The powder can be carried by water, allowing it to move easier, which means that bone meal can reach the deeper layers of soil.

Smaller particles also mean that the nutrients are made available to the plants faster, which is especially important during the growing season.

Since the nutrients in bone meal like phosphorus and calcium are released through microbial activity, smaller particles help because they can be processed easily. The microbes can eat through smaller particles quickly, which releases nutrients and makes them available for uptake by the plants.

9. Use Bone Meal To Fertilize Root Vegetables and Bulbs

Root vegetables and bulbs are plants that need extra phosphorus to support their solid roots, which store a great deal of the plant’s nutrient reserves. Phosphorus ensures healthy, strong root systems, which is especially important for root vegetables and plants with rot bulbs.

Supplying phosphorus through organic fertilizers like bone meal is especially important for root vegetables and bulbs because they typically need more phosphorus than other plants. Organic fertilizers are preferred in this case as the roots that are in direct contact with the fertilizer are also the part of the plant which will be consumed, making the use of bone meal ideal.

10. Apply Bone Meal to Flowering and Fruiting Plants

Phosphorus benefits plants and helps them achieve high yields by encouraging flowering, bud set, and fruiting.

Phosphorus also improves disease resistance in plants, which is especially important during the flowering and fruiting seasons, when all the plants’ resources are focused on reproduction. Applying phosphorus at this time can help reduce the number of pesticides necessary since the plant will be more resistant to pests.

Phosphorus also helps fruits ripen, which can reduce yield times in your ornamental plants and fruiting trees.

Conclusion

When fertilizing with bone meal it is helpful to keep the following things in mind:

  • Ensure you’re only using as much as necessary.
  • Mix it in with the soil whenever possible.
  • Powder it into fine particles before application.
  • Use it to mitigate phosphorus and calcium deficiencies.
  • Apply bone meal to support root growth and high yields.

Bone meal can be an excellent addition to any high-quality soil, but knowing how to properly make use of it will help you amplify its positive effects on your plants.

Alexander Picot

Alexander Picot is the principal creator of TheGrowingLeaf.com, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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