What Are Soil Amendments?

Think about how much time and energy you’ve focused on preparing your growing plot for the upcoming season. If you’re like other dedicated hobbyist gardeners and commercial farmers, you’ve spent hours at the desk and in the greenhouse planning the planting layout of different vegetables or flowers. You’ve worked to ensure proper crop rotation from previous growing seasons, checked your irrigation systems, and provided necessary maintenance to your equipment. 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? But do you spend time thinking about soil amendments?

Soil amendments are worth it when it comes to harvest results. Growing either as a hobby or a profession isn’t a set-it-and-forget-it activity, but amending the soil can be one of the most important things you can do to ensure a successful yet lower-maintentance growing season. Enhancing the health of your soil –the environment in which the roots of your plants will either wither or thrive– can help overcome many issues that arise over the course of your season.

It’s rare gardens and farms naturally have ideal loamy soil that’s the right ratio of sand, silt, and clay, as well as contain balanced bacterial or other microbial communities that enable optimum nutrient and water uptake for healthy, hardy plants. The great thing is we are not stuck with working with what we have, and there are answers 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 amendment for a vegetable garden or a flower garden?” Luckily, most plants tend to appreciate the same qualities in soil, so improving your soil overall is a good approach. Once you have done this, you can spend more time researching crop-specific needs, like for root crops, flowers, or leafy greens perse. Here, we offer a guide to creating a robust growing environment for your crops and the harvests that will follow. 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 ground that serves as a substrate for agricultural purposes isn’t as fertile as it might be. Your garden or farm plot might not be that bad, but it’s likely at some point or another, your land has seen impacts from phenomena that degrade soil quality over time. 

Examples of could include:

• Changing rain patterns
• Increased salinity levels due to overfertilization or other salt sources
• More productivity demands and intensive growing
• Overgrazing resulting in soil erosion
• Pollution
• Use of agrochemicals
• Compaction caused by construction, tillage, or other practices

It’s just an inconvenient reality: Soil that is farmed on and isn’t amended strategically, 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.

 

In general, the best soil amendments will help improve soil structure and soil nutrition. For example, certain amendments can improve porosity and permeability of clay-heavy soils. Or,  by amending sandy soils, we can improve their capacity for holding water and nutrients. The right soil amendment for hard soil can turn an unfarmable rhizosphere into an amenable environment for a healthy root structure. 

What are Soil Amendments?

Broadly, there are two types of soil amendments. A product can either be inorganic: usually made in a laboratory, or taken from a mine; or, it can be made from something that was once (or is still) alive. The latter are known as organic soil amendments. See below for examples of each of these. 

What is the best soil amendment for your land? 

The “best” soil amendment depends on a wide variety of conditions. Geographic, climatic, and planting conditions are unique to every plot of land, and natural products rarely work equally well in all situations. For example, adding sand to clay-based soil will make it harden like concrete. Wood ash may work well in some soils, but not when pH and salinity levels are already high. Luckily, more and more products are arriving on farm supply shelves and online retailers to address the diverse needs of growers.

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 

How to Amend Soil to Avoid Common Problems

The biggest challenge that growers have when creating a plan for how to amend soil is often overcoming a “more is better” philosophy. This is definitely not always the case. For example, if there are salts in a manure, roots may suffer from salt burn, so light to moderate use is often best. Each type of soil amendment has pros and cons, so determining what works best for your situation starts with an in-depth understanding of the current quality of your soil. Soil tests are often useful for determining salinity, pH, bacterial content, nutrition, or soil type in your farm or garden. Here are a few words of caution when choosing among 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, a byproduct of sewage treatment, should not be used on vegetable gardens. While beneficial to some kinds of soil, it can be 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 product consistency can vary dramatically. Purchased compost may be made from a wide variety of agricultural byproducts, biosolids, plant-based compost, or manures. Plant-based products naturally have the lowest salinity levels but can be quite expensive. 

Timing. What is the best soil amendment for a garden? 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, though you’ll have to wait longer 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 especially want to know if your soil has high salinity levels. Bagged, commercial compost often contains higher salts, and can even vary from batch to batch.
2. Aerate the top 6 to 8 inches of the soil area, and mix the amendment well into the soil. If the soil amendment is too shallow, it can 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. A rule of thumb: For the first three years, add plant-based composts 2 to 3 inches deep, but higher salt amendments only 1 inch deep before mixing thoroughly into the soil. After the fourth year of using soil amendments, amendments can be added at a shallower depth of 1 to 2 inches before being mixed well throughout the rhizosphere. 
4. Check your soil type and texture. You are shooting for soil that holds moisture well, but not for too long. If the texture is not ideal, balance it with additional materials.
5. 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. See below for comments on what supplements to choose alongside your amendment. 

Tips for Finding the Best Soil Amendment Suppliers

When searching for amendment suppliers, look for products with an independent certificate of analysis (COA) from the U.S. Department of Agriculture as a certified bio-based product. Organic 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.

And, Support Your Amended Soils!

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

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.

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. 

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.