Clay Soil Pros and Cons: How to Improve Clay Soil

Clay soil is a type of garden soil identifiable by its compacted, thick, and sometimes sticky texture. When clay dirt is dry, it often breaks off into crumbly clods; when it’s wet, it’ll stick to your shoes easily. Clay particles bind well with nutrients, but they’re also so thick that they make it hard for plants to extend their roots through them.

All loam soils—the recommended soil type for gardening—contain some amount of clay, alongside silt and sand. You can label soils as clay soils specifically when more than forty percent of the particles are clay. When over fifty percent of the loamy soil structure is clay, it’s a heavy clay soil. If you don’t know what type of soil you have in your garden, you can always purchase a soil test kit or have a professional evaluate it for you.

Every loamy garden soil includes some aggregate of these three primary soil particles:

1. 1. Clay soil: This rough, thick, and heavy soil makes it hard for many different types of perennial and annual plants to grow. Its mineral particles attract plenty of nutrients, but they also compact densely. Some plant types—like aster and hosta flowers, for example—are tough enough to make their way through the soil.
2. 2. Sandy soil: This gardening soil features a hefty amount of loose sand particles. While it’s much easier for roots to grow in sandy soil, it doesn’t retain moisture as well as clay soil does. That’s part of the reason why a combination is necessary.
3. 3. Silty soil: Comprising primarily silt particles, this rich soil is the midway point between clay and sand. It’s thick enough to retain moisture and loose enough to encourage growth. It still benefits most from having both other types of soil in its mix.

Clay soil has something of a bad reputation because of how difficult it is to grow things in it, due to the difficulty roots have with making their way through clay. However, there are advantages to clay soil, including:

1. 1. Drought tolerance: Since clay soil retains so much moisture, it’s very drought-tolerant. If there’s an ample amount of clay in your soil, your plants will have plenty of water to draw on throughout a dry season.
2. 2. Good nutrient density: Clay soil particles attract and bind to nutrients like calcium, magnesium, and potassium that feed plants and help them grow. The innate clay minerals also make for a healthy vegetable garden bed.
3. 3. Suitability to certain plants: Wet clay might make it hard for lots of plants to grow, but certain types are more than capable of growing in this nutrient-rich and moisture-rich soil. Think birch and hawthorn trees, or ivy and honeysuckle.

There are several reasons you might choose to avoid gardening in clay soil. Here are three of the most prominent:

1. 1. Reduced aeration: Dense clay soil binds together so tightly that the roots of your plants won’t receive much air. Most plants need that sort of aeration to truly thrive, making clay soil a detriment to your goals.
2. 2. Increased compaction: Dry clay prevents infiltration of roots throughout the ground by being so thick and sticky. This sort of compaction makes it difficult for plants to even start growing.
3. 3. Poor drainage: The danger in having a soil that retains as much moisture as clay is that it doesn’t drain very well. When your plants receive too much moisture, it can lead to root rot and other issues.

You can compensate for the weaknesses of clay soil to help your plants flourish. Here are three simple steps to clay soil improvement:

1. 1. Add soil amendments. To increase aeration and reduce compaction, add about half a foot or more of organic matter or other soil conditioning materials like grass clippings, wood chips, and other types of mulch to your clay topsoil.
2. 2. Mix organic matter into your garden. Next you can start combining the organic material and your clay topsoil with a shovel or tiller. This will lead to a slightly more raised bed in your yard, but it will pay off with increased and more efficient garden plant growth. This addition of the organic matter will break up the density of the clay as you mix it in, making it far easier for your plants’ root systems to stretch out.
3. 3. Plant cover crops. Now that your garden can host more diverse species of plants, make sure to plant some lush, leafy cover crops that will drop a lot of their own leaves and organic matter into the soil. These will release microorganisms and plant nutrients to automatically loosen the soil, so you don’t have to keep doing so manually.

Grow your own garden with Ron Finley, the self-described "Gangster Gardener." Get the MasterClass Annual Membership and learn how to cultivate fresh herbs and vegetables, keep your house plants alive, and use compost to make your community—and the world—a better place.