Your Ultimate Guide to Soil Amendments
Having healthy soil is the first and most important part of growing healthy, beautiful, and productive plants. Colorado soil is naturally very dense and clay-heavy and does not provide plants with the nutrient-rich, moist, well-draining soil that most of them require. That is where soil amendments come into play! Soil amendments can be used to change the consistency of soil, improve certain qualities, add nutrients, and so much more. So, if you have ever wondered what soil amendments are, wanted to know about the different types of soil amendments, or wondered how to amend soil, we plan to answer all of those questions right here in this blog!
What Are Soil Amendments?
Soil amendments are any material that is added to your soil with the intention of improving its physical properties. Such physical properties could include things like moisture retention, nutrient availability, drainage, aeration, and the like. Some of the most common soil amendments include compost, manure, sphagnum peat moss, wood chips, grass clippings, straw, sawdust, pea gravel, sand, vermiculite, and perlite, among others.
Why Amend Soil?
The main purpose of amending soil is to create an environment that suits the needs of any trees, shrubs, lawns, perennials, or annuals you may want to plant. Most plants are typically not able to grow in Colorado soil due to how dense it is, so the makeup, consistency, and physical properties of your soil must be adjusted to suit the needs of the plants you intend to add to your landscaping. Not doing so will lead to unhealthy plants that will not look nice and that are likely to die eventually.
Types of Soil Amendments
When amending your soil, it is important to know 1) what your soil needs and 2) which soil amendments to use to achieve the desired outcome. Below is a list of the most common soil amendments that are used in larger-scale landscapes, gardens, flowerbeds, and the like.
Compost has low to medium permeability and medium-high water retention. In general, compost refers to the recycling of organic matter such as food scraps, leaves, grass clippings, straw, and the like. You can make your own compost or purchase all-purpose compost from your local garden center. Things such as animal products, pet waste, fats, oils, and greases should never be composted. Compost adds nutrients while also aerating the soil and is one of the best soil amendments to use if you have clay-heavy soil.
Aged or composted manures are recommended as they are less likely to burn your plants. Chicken manure, sheep manure, or cow manure are generally the most common for use as soil amendments. Manure has low to medium permeability and medium water retention.
Grass clippings are another great material to add to your soil. Grass clippings will add nitrogen to your soil and will also help to increase the amount of organic material in your soil, which in turn helps to improve soil consistency, moisture retention, and drainage. Grass clippings are often used in gardens and landscapes alike and are great for amending clay-heavy soil.
Wood chips can help with moisture retention and are more often used as a top dressing rather than being mixed into your soil. Amending your soil with wood chips can cause a nitrogen deficiency in your plants, so be aware of this when using wood chips as a soil amendment. Wood chips or bark have high permeability, low-medium water retention, and can be useful when amending clay soils.
Pea gravel and sand will both have high permeability and low water retention. These inorganic soil amendments are often used to help the soil drain more freely, as they create space for water to escape. In certain situations, sand or gravel can also be applied as a layer along the bottom of your planting bed. This layer will act as a sort of reservoir for excess water to drain into and will help to keep the roots of your plants from sitting in excess water that could eventually cause damage.
In many cases, it may be recommended to mix topsoil in with your native soil or replace your soil altogether with quality topsoil. Topsoil often contains some soil amendments such as wood chips and other organic materials, however, the amount of organic materials is often limited, and further amending your topsoil, especially if it has been mixed with the soil originally in your planting beds, is highly recommended.
How To Amend Soil
Now that you understand the importance of soil amendments and their different uses, let's go over how to amend soil. Amending soil properly will be very important, as certain amendments could have unintended consequences. For example, adding too much manure to your soil could increase ammonia levels in your soil to the point of causing burn damage to your plants.
1. Conduct A Soil Test
While you may be able to tell what type of soil you have or what properties your soil is lacking, conducting a soil test is highly recommended. Soil tests help you understand the composition of your soil and will help you understand exactly what amendments are needed. To learn about different kinds of soil, check out our blog! You can also learn more about soil tests here.
2. Purchase Soil Amendments
Based on your soil test, head to your local garden center to pick up some soil amendments. Bath Garden Center & Nursery carries a variety of landscaping amendments such as Mushroom Compost, Sheep & Peat, All-Purpose Compost, and more!
3. Amend Your Soil
Now it is time to add your amendments to your soil. Most amendments will have application instructions on the back of the package. Follow these instructions to make sure you add the right amount. Adding too much of an amendment can have adverse effects, so follow the instructions carefully! Mix your amendments thoroughly to ensure they are dispersed evenly throughout your soil.
4. Plant Your Plants!
Now that your soil is amended, it is ready for your plants! If you are planting trees or shrubs, you can refer to our Tree & Shrub Planting Guide for instructions on how to properly plant larger plant material. If you are unsure of what to plant, check out our Plant Finder for plant ideas to suit your space. You can also come into the Garden Center to shop hundreds of plants in person.
Ardoin, Jordan. "What Are the Different Types of Soil Amendments?" Lawn Love. 16 June 2022. Web. Date accessed: 13 June 2023. Retrieved from: https://lawnlove.com/blog/types-of-soil-amendments/
Davis, J.G., Whiting, D. "Choosing a Soil Amendment" Colorado State University Extension. Web. Date accessed: 13 June 2023. Retrieved from: https://extension.colostate.edu/topic-areas/yard-garden/choosing-a-soil-amendment/