Types of Soil
Whether you’re working in your backyard garden or filling containers, the right soil can make all the difference in achieving green success. Soil anchors a plant’s roots, facilitates its water supply, helps it breathe and offers the nutrients it needs to support growth.
This guide will help you test the properties in the soil you already have in your yard to determine what amendments you should add to help your plants thrive.
Tip: If you’re planting directly into the ground, you can use amendments to improve your native, in-ground soil. When planting in containers, use a potting mix specifically formulated to provide adequate drainage and space for roots to grow.
Soil is one of the essential building blocks to growing strong, healthy and beautiful plants. Different plants need different types of support from their soil, so it's important to determine what you’ll be planting before you pick out the corresponding soil.
Your soil’s pH level reflects its acidity; pH is measured on a scale from 0 (most acidic) to 14 (most alkaline). Plants tend to grow best in soil with a pH between 6 and 7, but certain edibles and grass species prefer more extreme levels.
Before shopping for soil amendments, do a quick soil test of your native soil using a simple pH test kit. This will help you determine if you should increase the pH with lime or reduce it with sulfur.
There are three components of soil: sand, clay and silt. Most soil is a combination of these three. Depending on your region, your soil may be sandier or have more clay. Perform a “feel test” to give you an idea of what kind of soil is most prominent on your property.
- Moisten a tablespoon of soil and roll it into a small ball.
- If the ball packs together and is moldable, your soil contains clay.
- If you can form a 2 to 3-inch ribbon with your ball of soil, you have very high clay content.
- If the ribbon falls apart or feels gritty, you have a mix of clay and sand.
- If the soil ball will not hold together regardless of how much water you add, and it feels a little gritty, it’s sandy soil.
Good soil is formulated to address specific planting needs. Soils can be premixed and ready to use, specially formulated for use with certain plants, or you can find individual amendments to add to your native, in-ground soil to improve the composition.
- Increases the soil’s ability to retain moisture and nutrients while also improving drainage
- Can absorb 10 to 20 times its weight in water
- Compost and all manure types enrich soil and boost its fertility
- Helps soil to release nutrients to a plant continuously over long periods of time
- Added to soils to help prevent compaction
- Often used to help native soil that has been damaged
- Used to promote strong root development
- Improves drainage and aeration when added to potting soils
- Derived from volcanic rock that’s been crushed and heat-treated into white, lightweight particles
- Added to soil to help increase air space and improve water drainage
- Increases the pH of a potting mix to around 6.0
- Ideal for plant growth in containers
- Helps lower soil pH by canceling out excess alkalinity
- Provides plants with iron for lush, green growth and enhanced water filtration
Different plants thrive with different types of soil. Carefully read the amendment and potting mix labels to ensure you’ve made the right choice for your plants. And remember, it’s important to keep them properly watered and fed. Feed your plants one month after planting.
Topsoil has different grades that are used for different occasions. Lower-grade topsoils are great for filling and leveling holes and should only be used for that purpose. Higher-grade topsoils are great for conditioning the native soil and adding organic matter to the native soil. Neither should be used when planting.
Garden soil is a pre-mixed blend of organic matter and nutrients. It is designed to be mixed with your native soil to provide a foundation for your plants by improving common deficiencies such as high or low pH, lack of nutrients and soil compaction. Garden soil is intended for in-ground use only.
Raised bed soil is used when building a raised bed on top of your native soil. Garden soil and native soil are too dense by themselves to provide adequate aeration and drainage in a raised bed. You can either combine a 50/50 mixture of potting mix and garden soil when filling a raised bed or use pre-mixed raised bed soil.
Tip: If your native soil is less than ideal, planting above ground in a raised bed can be the simplest path to success.
Potting mixes are specifically formulated for use in containers as they create adequate drainage along with providing space for roots to stretch out. As the size of a container gets smaller, the importance of these benefits gets larger. Since their roots can’t travel far to find the food and water that they need on their own, plants need the little extra help a potting mix can provide. Potting mix should be replaced annually. Native soil and garden soil are often misused in containers. They don’t provide the necessary drainage, airflow and room for roots to grow when used in containers.
- In order to thrive, trees need soil fortified with phosphorus and iron to promote root development and prevent leaf yellowing.
- Soil that provides continuous release plant food will help establish strong roots.
- Soils with a mix of composted materials, fertilizer and water control additives can provide the best general support for a lawn.
- Look for soils that contain organic materials like peat moss to allow for adequate drainage.
- Adding compost to the soil can help offset any deficiencies in the nature of the native soil.
- Lighter soils give flower roots room to grow and spread, which helps anchor them.
- Every flowering plant has its own specific needs; while following these general guidelines, be sure to research the more specific needs of your various flower varieties.
- Plant edibles in soil that can help manage moisture to protect your garden from over- or under-watering.
- Add compost and organic materials to your soil as needed to ensure your edibles get the nutrients they need for growth.
- Fruits and vegetables often have greater water requirements than non-edibles. Be sure to follow the watering prescriptions for each type of edible plant you have.
- Succulents need very little water, so soils with additives like peat moss, sand and perlite help with drainage and prevent soil compaction.
Many packaged soils contain added nutrients to help plants get a quick boost or to keep them fed continuously during the growing season.
Nitrogen, phosphorus and potassium are some of the most common nutrients used in this way. When choosing your soil, look at a product’s label to see how long they will keep a plant fed. Some soils feed for up to three months while others are formulated with nutrients that keep a plant fed for up to nine months.