Organic soil additives – How to improve your soil

This post was most recently updated on March 16th, 2020

In a previous post we looked at how to turn bad soil into good soil, and in it we discussed adding organic amendments to the soil to improve its structure and function. Improving the soil for your garden is a complex topic, and I suggest that you also read that post. Read on to find out what organic soil additives you should add to your vegetable garden soil

Please read: This information is provided for educational purposes only and is not intended to treat, diagnose or prevent any disease. We encourage you to make your own health care decisions in partnership with a qualified health care professional.

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Organic soil additives for Healthy Soil

Adding plenty of organic matter to soil for organic gardens is critical in the health of your plants. Compost and manure are the most common organic soil additives. Here are some easy to get and common organic soil amendments for creating healthy garden soil in your garden.

1. Compost

A strong organic garden begins with compost. What exactly is compost? It is simply deteriorated, rotted organic matter.

You can make your own compost with household cooking scraps, leaves, grass clippings, etc.

The longer your compost bin is allowed to process the contents, the better the resulting compost will be.

To add compost to your garden you work it into the existing soil before spring planting and you can add more later in the summer if you plan to also grow an autumn/ fall garden.

RELATED POST: Benefits of compost

2. Manure

Manure is another very popular organic fertilizer among gardeners. It is perfect for adding organic matter to soil as well as beneficial bugs, bacteria and fungi.

The manure from cows, horses, goats, rabbits, and chickens are all considered to be very good for your garden.

You can buy manure from garden centers, local farms or if you are lucky enough to have your own grass eating animals, you can get it for freeeeee.

With manure you need to be aware of putting it on fresh to your garden space as it can burn the plants, this is especially true of chicken poo. Rabbit is the only manure that you can apply immediately to the garden without risk to your plants.

For everything else it is best applied in late autumn/fall after all your plants have been harvested, otherwise you can add it to your compost pile to age.

RELATED: What to do with chicken poop

3. Organic Soil Fertilizer Mixes

There are a number of other organic soil fertilizers you can add to the garden. Many of these you can make yourself at home, if you have a stomach strong enough to stand the stench!

Fish emulsion and seaweed tea, can do wonders for your soil.

Blood and bone meal is another, somewhat cheaper, alternative and as it is dry, it is less gross to handle and apply.

Comfrey tea is a great option, as it doesn’t smell nearly as bad is rotting fish heads do.


4. Mulch

Mulch is one of my favorite soil amendments. You can read more about the wonders of mulch here.

Mulching is the practice of using straw, hay, or (my favorite) woodmulch around the plants in order to keep weeds from overtaking your garden.

Usually a gardener would apply a layer of mulch all around the plants and in the walkways to deter the growth of unwanted plants.

Other Ideas for Organic Amendments for the soil

Alfalfa Meal – This is a great plant source of nitrogen that is easy to apply
Blood Meal – Often combined with bone meal it is a slow release nitrogen source also full of trace minerals
Bone Meal – Often combined with blood meal it has a quick uptake by plants
Chicken Manure – Composted it will delivers a well balanced supply of nutrients, don’t apply it fresh it is very high in nitrogen and will burn your plants.
Coconut Coir – This is made from compressed coconut fiber, eco-friendly peat alternative!
Dolomite Lime – raises pH in acidic soils, promotes healthy plant growth.
Green Manure Crops – You can grow cover crops to dig in to the soil
Greensand – contains potash, iron, magnesium, and up to 30 other trace minerals.
Gypsum – Used to loosen heavy clay soils
Kelp Meal – great source of micronutrients 
Peat Moss – This is a great way to loosen your soil, but it is not an ecofriendly choice, as our peat bogs are at risk of depletion. Coconut coir is a good substitute 
Rock Dust – Contains a broad range of trace minerals
Rock Phosphate – Contains phosphate, elemental calcium and other trace minerals.
Shellfish or Oyster Meal – calcium source, nitrogen, phosphorus and trace minerals. 
Sulfur – Makes your soil more acidic, great around acid loving plants such as blueberry, azalea and rhododendron.
Sul-Po-Mag – Also known as sulfate of potash-magnesia, a quick release source of potassium
Worm Castings – the most nutrient dense organic compost available. 

RELATED: Turn bad soil in to good soil

Why Are Organic Soil Amendments Better for the Soil?

When comparing organic and inorganic (commercial) soil amendments, it may seem that the inorganic additions are better because they deliver a bigger boost of nutrients in an easy to apply package.

However, in the long term, organic soil amendments deliver more nutrients in a steadier and more usable fashion and they are better at improving other important areas of the garden.

Organic soil amendments work to improve overall soil condition and structure, as well as delivering nutrients directly to your plants. Organic amendments also help to feed microbes and bugs in the soil.

Adding additional organic matter to your soil also improves:

  • Soil structure
  • Moisture retention
  • Drainage
  • Feeds the fungi

How Organic Amendments Build Healthy Soil

It is very rare to find perfect soil. Most gardens have wither too much sand, too much rock, too much clay, high acidity or other things.

Transforming your soil from bad to good is possible. It does take a series of specific steps depending upon the type of problems with your soil. 

Soil is made up of four elements:

  • Organic matter
  • Weathered rock
  • Water
  • Air

These form the basic building blocks of all soils. Truly healthy soil requires a thriving population of other things like:

  • Microbes
  • Insects
  • Worms
  • Fungi
  • Friendly Bacteria
  • Beneficial Mites
  • Nematodes
  • Springtails
  • Protozoa

As you add more organic material to your soil, you will increase the populations of all the beneficial microbes, insects and fungi.

These very small creatures help to convert the soil minerals along with the organic matter that you provide into disease suppressing compounds, nutrients, vitamins and hormones that are absolutely necessary to successful plant growth.

Once you know the benefits of all these little bugs it makes it easy to see that as a successful gardener, you will be far better off focusing on creating ideal soil conditions to support these organisms than on simply providing plants with synthetic nutrients.

If you are new to gardening, or want some support and knowledge getting a garden started, check out our Productive Gardener Course TODAY

Green Manure & Cover Crops

Green manures and cover crops provide a way of protecting your soil from weeds, loosening the soil, adding nutrients and enriching soil structure before it is used for growing other plants. 

Cover crops

To protect the soil over the winter choose a  cold hardy crop such as winter rye grass or vetch. When spring arrives, you can dig this crop under to add more nutrients to the soil.

RELATED: Cover crops 

Green Manures

Crops such as:

  • Buckwheat
  • Soybeans
  • Field Peas
  • Legumes
  • Alfalfa
  • Tic beans

are considered green manures.

Like animal manure, these plants provide a great deal of nitrogen and organic matter to your soil. As a bonus, they grow very densely and choke out weed growth.

With either cover crops or green manures, you must be sure to dig them under a minimum of three weeks prior to planting the area in your main crop.

This gives the organic matter a chance to start breaking down by the time that you are ready to plant.

Organic amendments are the best things to add to your soil to naturally improve your soil in your garden. If you need more information about growing a garden, check out our Free Gardening Resources here.


For further reading, I really recommend all of these books. I own every one of them and they are amazing resources!

Growing great vegetables and flowers required great soil. Find out which organic amendments are best for your soil here



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