What Are Soil Amendments?

 Think about how much time and energy you’ve focused on preparing your growing plot for the upcoming season. It probably hasn’t included much thought about soil amendments.

If you’re like other dedicated hobbyist gardeners and commercial farmers, hours are spent at the desk and in the greenhouse planning the planting layout of different vegetables, flowers, and possibly cannabis plants. You’ll work to ensure proper crop rotation from previous growing seasons, check your irrigation systems, and provide any necessary maintenance to your equipment. 

Is there a hole in your glove? Are there better companies from which to source your seeds or seedlings? Does the upcoming weather forecast help or hinder what you want to grow? 

Thinking the process out takes time, and it’s always worth it when it comes to harvest. Growing as a hobby or a profession isn’t a set-it-and-forget-it activity, and all the time away from the land is important — but it’s far from the most important thing you can do to ensure a successful growing season.

Enhancing the health of your soil — the environment where the roots of your plants will either wither or thrive - can help overcome many issues that arise from a lack of planning or other natural conditions that may result from events or situations you just can’t plan for. 

It’s so rare that gardens and farms have ideal loamy soil that’s the right ratio of sand, silt, and clay as well as contains the proper balance of bacteria and other microbial communities that facilitate proper nutrient and water uptake for healthy, hardy plants. Some growers might think they’re just stuck with working with what they have, but there’s an answer to problems in the soil.

Natural soil amendments are the solution. A soil amendment is loosely defined as any material that can improve the physical qualities of agricultural land. 

You may wonder, “What is the best soil amendments for a garden?” This guide will provide everything necessary to focus your energy on creating a robust growing environment for your crops — a required priority for abundant harvests. Read on to learn:

  • Why Soil Amendments Are So Necessary
  • What are Soil Amendments?
  • Types of Soil Amendments
  • How to Amend Soil and Avoid Common Problems
  • Tips for Finding the Best Soil Amendment Suppliers 

Why Soil Amendments Are So Necessary

Unfortunately, much of the arable ground that serves as a substrate for agricultural purposes isn’t as fertile as it could be. Think back to the Dust Bowl of the 1930s, when catastrophic winds and a lack of rain caused massive erosion and soil degradation that impacted food supplies during the desperation of the Great Depression. 

Your garden or farm plot might not be that bad, but it’s likely the land has seen impacts from other phenomena degrading the soil quality over time. Examples of this could include:

  • Changing rain patterns
  • Increased salinity levels
  • More productivity demands from intensive growing
  • Overgrazing resulting in soil erosion
  • Pollution
  • Use of agrochemicals
  • Compaction caused by construction or recreational uses
  • Past unsustainable farming practices

It’s just an inconvenient reality: Soil that isn’t amended and improved through a strategic regime will lose its fertility over time. And in many places in the world, the land might not have even been that great in the first place. As a farmer or a gardener, you can make a dramatic difference in crop productivity simply by adding soil amendments to your land.

adding soil amendments


The best soil amendments will help improve the porosity and permeability of clay-heavy soils. Sandy soils, with the help of organic soil amendments, can improve the capacity for holding water and nutrients. The right soil amendment for hard soil can turn an unusable rhizosphere into an amenable environment for a healthy root structure. 

What are Soil Amendments?

There are two types of soil amendments. A product will either be inorganic, made in a laboratory, or taken from a mine, or it will be made from something that was once alive. The latter is known as organic soil amendments. 

Then, there are what is known as a biotic soil amendment, which is created from a mixture of organic and inorganic materials.

What is the best soil amendment for your land? 

That depends on a wide variety of conditions. With geographic, climatic, and planting conditions being unique to every plot of land, few natural products can work in all situations. For example, adding sand to clay-based soil will make it harden like concrete. Wood ash may work well in some soil, but not when the pH and salinity levels are already high.

Since consistent sourcing of natural soil amendments can be challenging — especially for growers looking for bulk soil amendments — more and more products are arriving on farm supply shelves and online retailers to help land stewards with all sizes of growing spaces improve their soil.

Types of Soil Amendments

Types of organic soil amendments:

  • Sphagnum peat
  • Wood chips
  • Grass clippings
  • Compost
  • Straw
  • Manure
  • Sawdust
  • Wood ash
  • Biosolids

Examples of inorganic soil amendments:

  • Perlite
  • Chunks of old tires
  • Vermiculite
  • Pea gravel
  • Sand

Then, there are the products that combine modern agricultural technology to support best practices for organic growing.

Impello’s Lumina Organic Amino Acid Fertilizer combines amino acids and polypeptides to create a bioavailable source of plant nutrition by amending the soil. Not only does this product offer added nitrogen through potash, molasses, and shrimp protein, but it also includes the proprietary technology that enhances the soil’s beneficial microbes that the company is so well-known for.

This fertilizer provides the nutrients roots search for as they push through the soil while also improving the health of the soil itself. It’s been shown to improve crop tolerance to abiotic stress or other forms of inefficient management. 

That’s right: Products like Lumina improve harvest quality, yields, and overall plant performance by creating an environment in which your crops will thrive. Using it in combination with the right soil amendment can make gardens and farms thrive.

soil amendments


How to Amend Soil? Avoid Common Problems

The biggest problem growers have when creating a plan for how to amend soil is overcoming a “more is better” philosophy. Roots can easily suffer from salt burn, causing garden plants to die. Beware of using too many dry soil amendments. 

Each type of soil amendment has its pros and cons, so determining what works best for your situation starts with an in-depth understanding of the current quality of your soil. Depending on the size of your growing plot, you may want to administer numerous soil tests to know the salinity level, the pH, bacterial content, and soil type in your farm or garden.

Some things to consider when choosing among the different soil amendment options:

Wood products require time in the compost bin before they can be added to the soil. When wood products break down, the microorganisms in the surrounding area use nitrogen as part of the decomposition process. This leaves less nitrogen — a crucial nutrient for plant growth — available for your crops, so be sure to add a fertilizer along with this option.

Biosolids, which are the byproducts of sewage treatment, should not be used on vegetable gardens. This product, while beneficial to many kinds of soil, is usually high in heavy metals like cadmium and lead. It also can have a very high natural salinity level. 

Compost is often considered a one-step soil conditioner, but consistency can vary dramatically. Purchased compost can be made from agricultural byproducts, biosolids, plant-based compost, or manures. Plant-based products naturally have the lowest salinity levels but can be quite expensive. 

What is the best soil amendment for a garden? You’ll see the best results if you know the tradeoffs. Amendments that break down quickly in your rhizosphere will work in a shorter time frame but won’t last as long. Amendments that take time to decompose will create longer-term benefits, even though you’ll have to wait to see results.

5 Steps to Adding Soil Amendments

For effective use of soil amendments, follow these 5 steps:

  1. Test your soil. You’ll want to know especially if your soil has high salinity levels. Bagged, commercially produced compost often contains excessive salt content, and the salinity can even vary from batch to batch.
  2. Aerate the top 6 to 8 inches of the soil area, as any soil amendment must be mixed well into the soil. If the soil amendment is too shallow, it will result in shallow roots.
  3. Mix in the soil amendment at the proper depth, which depends on how many growing cycles you’ve added materials to improve the soil quality. For the first three years, make sure plant-based composts are at least 2 to 3 inches deep, while higher salt amendments should only be 1 inch deep before mixed thoroughly into the soil. 

After the fourth year of using soil amendments, it can be added at a shallower depth of 1 to 2 inches before being mixed well throughout the rhizosphere. 

  1. Check your soil’s texture. Once the soil amendment is added, your land should be able to hold moisture and store nutrients properly. Water should be able to drain well, too. If the texture is not ideal, balance it with additional materials.
  2. Add fertilizer and microbial inoculant. It’s crucial for soil health that the microorganisms in the soil are also supported after the addition of a soil amendment. Impello’s Lumina should be applied every 1 to 3 weeks along with a typical fertilizer regime. It can be combined with Tribus Original for both foliar and root drench applications throughout the growth cycle.

Tips for Finding the Best Soil Amendment Suppliers

When searching for the best soil amendment suppliers, make sure the products they sell have an independent certificate of analysis (COA) from the U.S. Department of Agriculture as a certified bio-based product. Products should also be listed on the Organic Materials Review Institute, or OMRI.

Suppliers should be transparent when showing the ingredients, so you are aware of exactly what you are using on your soil. Look for naturally derived materials. The best products are also highly concentrated, so you don’t have to use a lot. 

Finally, make sure you purchase your products from a supplier that guarantees your satisfaction. When you spend the time and energy you do on creating the best environment for your farm or garden, you’ll want to be sure that the companies you work with care just as much about your harvests, too.

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