Understanding Soil Types and Their Impact on Drainage

Proper drainage is an invaluable part of landscaping that requires a little planning to achieve. It can be difficult to know what type of or how much drainage your yard needs if you’re unfamiliar with your soil type. In this post, we’re going to explain the different types of soil, how to support their drainage types for optimal growth in your yard, and how to choose the right plants for your soil type. Drainage Characteristics of Different Soils You can’t proceed with your landscaping plans if you’re unsure of your soil and drainage type. Generally, there are three soil types: sandy, loamy, and clay, each with different drainage properties. Sandy Sandy soil drains water quickly because of its large particles and loose structure, which allows water to flow through gaps in the soil. These soils can drain water at a rate of 1-10 inches per hour, and it takes about half an inch of water to recharge a foot of sandy soil. As a result, they tend to dry out faster than other soil types and have low water and nutrient-holding capacity. Loamy Loamy soil is a mixture of sand, silt, and clay that’s known for it’s excellent drainage properties. Its structure allows excess water to drain away while still retaining enough for plants. This prevents waterlogged roots, and also allows the roots to grow deeper and more easily. It’s full of nutrients and organic matter, retains a balanced pH, and has a crumbly texture that’s easy to work with. Clay Clay soil is the opposite of sandy soil in that it has a dense, sticky texture and small particles that are tightly layered together. As a result, it’s prone to compaction, especially when wet, and can harden into an impenetrable mass when dry. It’s also prone to shrink-swelling, where it expands when wet and contracts when dry, which can cause foundation issues if not handled appropriately. Safe to say, clay soil’s drainage is poor. Testing and Amending Soil Drainage There are several ways to test your soil to see what type of drainage it has. It is recommended to send a soil sample to a laboratory and let them run a full analysis, as this will give you information about drainage, composition, pH, nutrients, moisture, and other soil conditions that will help you landscape appropriately. However, if drainage is your priority, there is also a simple test you can do at home. Dig a hole in your yard 12 inches wide and 12 inches deep. Fill the hole with water and let it drain completely. Then, refill the hole with water and measure the water level every hour or two until the hole is completely drained. Calculate the average number of inches the water drains per hour to get your drainage rate. Generally, the ideal drainage time is between 10 and 30 minutes. If it takes less than ten minutes to drain, the soil is likely drought-prone, and if it takes much longer than 30 minutes, then you have poor drainage. Amending Soil Drainage The most recommended method for improving drainage is by adding soil amendments. Adding organic matter like compost, mulch, or well-rotted manure improves soil structure by increasing soil aggregation. This helps with drainage, water retention, overall soil structure, and makes soil nutrients more available for plant use. Other examples of soil amendments include grass clippings, gypsum, peat moss, wood chips or ash, topsoil, biochar, vermicompost, perlite, sawdust, and sand. Choosing the Right Plants for Optimal Drainage There are many factors to consider when choosing the proper plants for your space. Soil conditions, climate, and native plants are the most telling indicators of how well a plant will do. For example, if you have sandy soil, you want to plant native, drought-tolerant plants that work well in poor soil conditions. Some examples include lavender, salvia, allium, butterfly bush, rudbeckia, stonecrop, daylilies, and yarrow. Most plants grow well in loamy soil because of its good drainage properties, but plants like cacti or succulents may not grow well in this soil because it’s too moist for them. Some plants to consider for loamy soil are cornflower, hosta, black-eyed susans, roses, and big bluestems. Plants that grow well in clay soil have strong root systems that withstand the heaviness of the clay, like a little extra moisture, and can adapt to any soil condition. Some examples of plants that grow well in clay soil are smooth hydrangea, coneflower, beebalm, viburnum, and aster. Conclusion When your goal is to grow a healthy, vibrant landscape, sometimes it feels like there are so many disruptors in your way. That’s why your knowledge should start from the bottom up. Now that you know what you can grow with your specific drainage type, nothing will stop you from the beautiful yard you deserve.