How to Add Phosphorus to Soil? [5 Easy Tips!]

how to add phosphorus to soil

Just like us, plants require a certain amount of minerals and nutrients to live, and one of these vital nutrients is phosphorus.

If you are working with soil that is not ideal and their growth seems to have stalled, it may be the case that your plants do not have enough phosphorus. So, how can you add phosphorus to the soil?

The easiest way to add phosphorus to your soil is to use additives like lime, animal manure, bone meal, compost, and rock phosphate.

Besides nitrogen, phosphorus is the most essential mineral that plants need to survive, so there must be enough in your soil to sustain your plants.

This article is going to explore the function of phosphorus in your soil and give you some tips on how to add it to your soil.

Grow Your Yard Fact
If you have ever noticed the edges of your leaves going purple, you may be dealing with a phosphorus deficiency.

What is Phosphorus?

Phosphorus is one of the big three nutrients that all plants need for life, alongside nitrogen and potassium.

The plant acquires phosphorus by absorbing it through the soil, which is why we need to know when our soil might be phosphorus deficient.

This mineral has several functions that are key for promoting healthy plants. Here is a breakdown of the three primary nutrients a plant needs and why:

Nutrient Purpose
Phosphorus ●     Store and transfer energy produced by photosynthesis

●     Promotes root growth

●     Speeds up maturity

●     Improves rigidity

Nitrogen ●     Building blocks of plant proteins and enzymes

●     Enables photosynthesis

Potassium ●     Helps movement of water, nutrients, and carbohydrates

●     Regulates rate of photosynthesis

●     Enzyme activation

Grow Your Yard Fact
It’s not just plants that need phosphorus to survive, so do we! Phosphorus is key to forming bones and teeth, among other functions. Just like plants, we acquire phosphorus through our food.

How to Add Phosphorus to Soil

So, now that we know how essential phosphorus is to your plants, we’re sure you are keen to find out how to add it to your soil.

The first step you need to take is testing your soil to determine if a phosphorus deficiency is the problem. This can be done using a relatively affordable test kit that can be bought from your local nursery or online. After that has been determined, you know you need to use one of these interventions.

Here are five ways to increase the phosphorus in your soil:

1.   Lime Soils to Increase Soil pH

One of the critical ways to improve a plant’s phosphorus uptake is by increasing the soil pH.

Plants require a specific pH level to be able to absorb the minerals and nutrients that it needs to grow. The ideal pH level for phosphorus availability is between 6 and 7.5.

If you test your soil pH and it is sitting under 6, we suggest applying a layer of lime to your soil and digging it through. This should raise your soil pH to the perfect level for absorbing phosphorus and other nutrients. Water after applying to activate it.

2.   Compost

Compost is an organic material made of decomposed plant matter. It contains all the nutrients a plant needs to grow strong, including the all-important phosphorus. The great thing about compost is that you can make it at home at no extra cost to you.

Using compost is the ideal way of adding phosphorus to your soil because it essentially recycles your garden and food waste to create something that will help future plants to grow.

Apply a layer of compost to your garden beds and dig them over well before giving it a good water.

3.   Animal Manure

When animals eat plants, they take in phosphorus, and while some of it is used in the body, a portion of it is lost through its manure.

This means that animal manure is rich in phosphorus and adding it to your garden is a great way to increase the phosphorus levels. Luckily manure is an accessible and relatively affordable soil additive.

Horse manure will do, but if you want a higher phosphorus concentration, you need to use bird guano.

4.   Bone Meal

Bone meal is a soil additive made from ground-up animal bones containing high phosphorus levels.

You can add bone meal to your soil according to the packaging instructions, but we also suggest adding a handful of bone meal to your compost heap every few months to help break down the plant matter.

5.   Rock Phosphate

Rock phosphate is a sedimentary rock made up almost entirely of phosphorus.

Unlike the other options we’ve looked at, rock phosphate will only add phosphorus to your soil and no extra nutrients or minerals. To apply, add a layer of it to your soil according to the packaging instructions and dig over well to incorporate it into the soil.

Frequently Asked Questions:

Are Epsom salts phosphorus?

While they can be a handy soil additive, Epsom salts contain no phosphorus, nitrogen, or potassium as they are purely magnesium sulfate.

If you wish to use Epsom salts in your soil to add sulfur and magnesium, you should do so alongside your regular fertilizer to ensure the plants are still getting the rest of their nutrients.

What are the signs of phosphorus deficiency?

Identifying phosphorus deficiency can be very difficult because the symptoms are subtle and can be mistaken for many other issues.

The main sign is stunted growth. This may also be accompanied by the leaves and stems turning darker green, and the leaf edges turning purple.

Do coffee grounds contain phosphorus?

Coffee grounds can be used as an amendment for your soil to raise the acidity of your soil. They also contain nutrients, including 0.06% phosphorus, so while it is only a small percentage, it is still a source of phosphorus, so it won’t do any harm to add them to your garden or compost heap.


Phosphorus is a vital mineral that plays a massive role in a plant’s well-being, so ensuring your plants are getting enough is key to a healthy garden.

The five ways that we suggest adding more phosphorus to your soil are raising your soil pH and adding animal manure, compost, rock phosphate, or bone meal to your soil.

If you follow our handy tips, you are sure to have well-balanced soil that helps your plants thrive.

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