6 Fast Ways To Add Phosphorus to Soil Naturally

how to add phosphorus to soil
The best way to add phosphorus to soil is by using natural phosphate sources such as manure, eggshells, bone meal, and wood ash. You can also use phosphorus fertilizers such as DAP (Diammonium phosphate).

Phosphorus is an essential nutrient that plants need to grow healthy and strong. A lack of phosphorus can lead to poor growth, yellow leaves, and even the death of crops.

This is why many farmers add phosphate to the soil as a fertilizer. However, this practice leads to a decrease in soil content by about 10%. 

So how do you know how much phosphorus you should add to your soil.

6 Fastest Ways to Add Phosphorus to Soil

Below are some of the fastest ways to add phosphorus to soil:

1. Bone meal

It’s among the richest sources of phosphorus and is readily available too.

You can make your own by drying and grinding animal bones like chicken or getting an artificial bone meal from your local hardware store.

2. Seaweed/kelp

It’s available in liquid form and is rich in NPK (Nitrogen, Phosphorus, and Potassium).

3. Fish meal

Fish meal is similar to bone meal as it has a high phosphorus content and is readily available for plants to absorb. Also rich in nitrogen.

4. Rock phosphate

Unlike fish and bone meal, phosphate rock releases phosphorus slowly over long periods.

5. Clay soil

Some clay soils have high phosphorus concentrations. Be careful, though, because leaching occurs easily in clay soils.

6. Green manure

This organic matter is rich in phosphorus as well as other macro and micronutrients.

Why Do Plants Need Phosphorus

There are three macronutrients every plant needs for healthy growth:

  • Nitrogen
  • Phosphorus
  • Potassium

Phosphorus ensures strong root growth strong and can easily absorb nutrients from the soil. In addition to making absorption possible, phosphorus also forms an essential component in cell walls, reinforcing plant cells and keeping them upright.

Phosphorus is also vital in:

  • Cell reproduction
  • Flower and fruit production
  • Transportation and utilization of plant sugars
  • Photosynthesis
  • Energy transformation in legumes during nitrogen fixation

5 Common Reasons Why Soil Lacks in Phosphorus

There are several reasons your soil may lack phosphorus:

  1. Acidic soil
  2. Too much water/rainfall 
  3. Cold weather
  4. Herbicide use
  5. Poor soil health

How Do You Know Plants Need More Phosphorus?

Leafy plants and those with thick root systems typically require more phosphorus than others. This quality makes them the best indicators for low phosphorus levels.

So, what does phosphorus deficiency look like?

  1. Brown spots
  2. Leaves with extra dark shades of green
  3. Bronze, brown, and purple leaf edges
  4. Stunted growth – the plants don’t produce flowers or fruits during the growing season
  5. Small leaves with no new growth

How To monitor Phosphorus Levels in Soil?

1. Check Root-Zone Temperature

The optimum temperature for absorption of phosphorus by plants is ≥15 degrees.

Anything below this interferes with uptake and causes deficiency.

2. Test Soil pH

The standard pH for most crops is between 5.5 and 7.0. Phosphorus is a reactive element and will bind with other nutrients, hindering its absorption by plant roots.

When introduced to alkaline soils, phosphorus will bind with calcium and aluminum in acidic soils.

So ensure the pH level is at optimum levels to prevent deficiency by carrying out a soil test using a test kit.

3. Check Root Moisture Levels

Too much moisture at plant roots can cause phosphorus deficiency.

So to correct this, monitor how much water you give to plants to prevent waterlogged soil.

4 More Ways to Add Phosphorus to Soil Naturally

1. Through Organic Fertilizers Such as Compost

One way to add phosphorus to soil naturally is through mulching. Some components in compost are rich in this mineral and are an excellent way to boost the phosphorus levels in soil without using artificial fertilizers. Compost is also rich in soil organisms that further improve its fertility.

They include:

Although meat and dairy products such as fats and oils are rich in phosphorus, they shouldn’t be added to compost because they attract pests.

2. Wood Ash

Wood ash is a great source of natural phosphorus for soil. It’s rich in phosphorus as well as other nutrients like:

  • Magnesium
  • Potassium
  • Calcium

3. Bone Meal

Bone meal is rich in phosphorus, making it the number one source of phosphorus for plants. The reason is the mineral occurs naturally in bones, as well as potassium and calcium.

The components are released slowly over time as the material continues to break down, providing enough phosphorus for a single planting season.

Where do you get bone meal?

There are two primary sources you can consider.

They include:

  • DIY bone meal (Crushing and grinding the bones yourself)
  • Store-bought bone meal (artificial)

How to Make DIY Bone Meal


  • Animal bones – cow, fowl, e.g., chicken, turkey 
  • Pressure cooker
  • Mortar and pestle or food processor
  • Dehydrator


  1. First, clean the bones, ensuring no meat residue or cartilage.
  2. Please put them in a pressure cooker, fill them with water, then cook for two hours at high heat. The heat makes them easier to crush.
  3. Place the bones in a dehydrator once they’re done boiling. Leave them for 12 hours. If you don’t have one, leave them out to dry simultaneously.
  4. Place them in the food processor or mortar and pestle, then crush them till it has a powder consistency.
  5. It’s now ready for use!

Note: Be cautious when applying bone meal to the soil since it has a high phosphorus availability. When used in excess, it might cause harmful effects on plant growth. Excess phosphorus leads to the depletion of micronutrients such as zinc and iron. 

4. Banana Peels

Banana peels are natural sources of phosphorus. Unfortunately, you can’t add them directly to the soil; you’ll have to turn them into a liquid first.

Here’s how to do it:

  1. Get several banana peels, then cut them up into big chunks.
  2. Soak the peels in a liter of water inside an airtight container, then leave it for five to six days.
  3. After the sixth day, add another liter of water, then strain the liquid.
  4. The solution that you get after straining is what you add to the soil.


Discovering composting as a way of life or even better, as nature’s way of recycling, Ana dedicates her time to trying out new methods of composting at home. Her goal is to share everything that she’s learned in the hopes that it will help others discover the amazing rewards of composting.

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