Organic Amendments for Soil: Complete Guide


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Soil amendments can help your plants flourish. If your plants are looking lackluster or just not growing the way you expected, then look at the soil you are growing them in.

In this article, I will discuss organic amendments for soil in more depth. I’ll be taking you through what they are, the different types, and how to use them.  

What Are Soil Amendments?

Soil amendments are anything that you add to your soil to improve its quality. Soil amendments can be used to improve your soil’s texture, composition, as well as add nutrients. 

You can use amendments to improve soil structure for a specific purpose. Adding amendments to garden soil can improve drainage, or add plant specific nutrients like potassium or nitrogen. 

To find your soil’s nutrient balance levels, you can send your soil away for testing. However, if you have soil that is a good mix of sand, clay and silt as well as plenty of earthworms and other bugs, I would say your soil is good to go.

You can add organic amendments for nutrients that benefit the plants you are growing, but organic matter like a well-balanced compost will be just as good. 

Types of Organic Soil Amendments

There are 2 main types of soil amendment – Organic and Inorganic. 

Organic material are amendments that are alive like plants. Inorganic material are like volcanic rock. 

You can add these directly to the soil or put on your compost heap and mix them all in together. If you are digging it directly into the soil, you should wait a few months for it to decompose before planting anything.

Below I’m going to take you through some organic amendment options that you can use in organic gardening.

1. Plants and Plant Material

Plants and material derived from plants are an excellent source, things like grass cuttings, straw, leaves, and cut up twigs all work well. 

2. Kitchen Scraps

Anything like vegetable and fruit peelings, uncooked fruit or vegetables that are no longer usable. Other organic “trash” like tea leaves, coffee grinds, and egg shells are great to mix in as well. 

3. Aged Manure

You should only use manure from herbivores like chickens, horses, sheep, goats or cows. You can use pig manure, but ensure it is from pigs that have only been fed organically. 

4. Bark, Wood Chips and Sawdust

These should not be added directly to the soil as that can remove nutrients, so add these to your compost heap and allow them to decay.

5. Coco Coir and Sphagnum Peat Moss

Coconut coir and spaghnum peat are both commercially available and while they don’t add any nutrients they help the soil composition. They simultaneously aid drainage and retain moisture, as well as aerate the soil.

6. Cover Crops

Although these are more of a technique than an amendment, I’ve still included them on this list as they can improve the quality of your soil. Plants like clover, rye, and oats are planted in the fall, then mixed into the soil in the spring before planting main crops.

7.Other Matter

Things like clay pellets, pumice, and perlite aren’t technically organic matter, but they are natural and don’t contain any chemicals, so you can safely use them in organic gardens if you wish. They can retain moisture, break up and aerate soil.

Organic Soil Amendment Tips

The best tip for soil amendments is to start a compost heap. I am a massive advocate of compost heaps.

They are free to build, free to maintain and the compost you produce will be better than any store brought compost. Make sure you put in a healthy mix of greens and browns. 

Greens are classed as materials that are rich in nitrogen and protein like:

  • Grass clippings
  • Tea leaves
  • Coffee grinds
  • Vegetable and fruit scraps
  • Plant trimmings
  • Weeds
  • Eggshells
  • Animal manure

Browns are materials carbon or carbohydrate rich materials like:

  • Pine needles
  • Rotting leaves
  • Twigs
  • Straw or hay
  • Sawdust
  • Paper and cardboard – just make sure they don’t have any plastic or waxy coating
  • Cotton fabric

Final Thoughts on Organic Soil Amendments

Soil amendments are usually necessary, as having perfect soil naturally is rare. They are not a modern invention and farmers have added material to improve their soil for centuries.

Soil amendments are useful for all gardening, but really come into their own when it comes to vegetable gardens. You can use amendments not only to improve your soil, but to help keep it healthy and maintain its productivity.

Adding amendments to your soil at the end of each growing season will help your vegetables stay healthy and productive for longer.

When we talk about organic soil amendments, we are of course talking about amendments that are free from chemicals rather than ones that come from organic material.

As modern industrial farming methods have concentrated on the end product rather than sustainability, soil amendments are becoming more crucial.

Soil erosion and poor soil that has been stripped of nutrients are a consequence of many modern farming techniques, as well as a reliance on chemical fertilizers and pesticides.  

FAQs – Frequently Asked Questions

What is the Best Soil Amendment?

Compost is easily the best amendment that you can add to soil. It can add moisture to sandy soil, break up clay soil, help control erosion, as well as provide valuable nutrients.

What is the Best Kind of Organic Matter to Add to the Soil?

Well-rotted aged herbivore manure is a great organic matter amendment to add to any soil. Be sure the manure was piled for over 6 months or the ammonia levels could be too high and harm plants. 

How Do You Amend Soil Cheaply?

The best way to amend soil cheaply is to build a compost heap. There are various designs online, and you can build one for next to nothing or even free. Add any organic materials you have like garden clippings and vegetable peelings. With help from various insects and bugs it will break down into compost for free.