Written By Lara Wadsworth

Proper soil drainage is a major part of a successful garden. When the soil retains too much water and becomes soggy for long periods of time, it can cause problems with plant health, inhibit root growth, and increase the chances of disease. Plants need water, but they also need air around their roots to respire and, therefore, develop properly. Poor drainage causes issues such as root rot, which results in leaves turning yellow and, eventually, plant death. But do not fear! If you have suffered from poor soil drainage in the past, you can amend the soil and improve things drastically. Here’s how:

Identify the Cause of the Poor Drainage

Don’t let soggy soil stop you from gardening! In order to understand how to fix poor soil drainage, it is important to understand what causes it in the first place. It all has to do with the texture and composition of your soil. Soils that have high percentages of clay, are compacted, or are low-lying are notoriously bad at draining and prone to water accumulation. Poor drainage is almost always caused by one of those three problems.

Symptoms of poor drainage include water pooling on the surface more than an hour after irrigation or rainfall, yellowing or wilting leaves, root rot, or fungal diseases. You may have one, a combination of a few, or all of these issues. You can check for root rot by examining the roots of the plants. This does involve uprooting the plant, but it is the only way to know for sure if you have root rot. Look for dark, soggy-looking sections of the roots that literally look like they have begun to rot away. You can try to save a plant by cutting off these sections and replanting it in a pot or garden bed with good drainage. Some plants take well to this interference, and other plants will just die anyway, so it’s worth a shot!

How to Test Soil Drainage

Test your soil drainage by digging a hole 12-18 inches wide and deep and filling it with water. Let it drain overnight. Then, fill the hole with water again the next day and time how quickly it drains. You have good drainage if it drains in 10-30 minutes. If it takes longer than 30 minutes, soil amendments will do you well! If it takes less than 10 minutes, you might need to increase water retention. Check out our other blog about increasing water retention if that is your issue.

Methods to Improve Soil Drainage

Once you know what is causing the poor drainage, you can move forward with the right actions to remedy the issue.

Level the Growing Area

If the poor drainage is caused by a low spot, you must either lower the ground around your growing area, or raise your soil line. My guess is you would rather raise the soil line of your growing location. This can be done by adding topsoil from your local garden center or green waste facility. If you try to amend the soil in a low spot you may end up masking the problem with soil that drains too quickly. Soil that drains quickly and receives a lot of water, such as a low spot, may experience nutrient leaching. This is when the nutrients get washed below the root zone and become inaccessible. You’ll want to treat the problem, not the symptoms.

Amendments for Improving Soil Drainage

To improve a soil’s ability to drain you will want to amend it with a material that creates pore space. This can be done by adding inorganic materials like sand, perlite, or vermiculite. You can also amend with organic matter like compost, peat moss, coconut coir, or leaf mold.

Sand - a popular choice for increasing soil porosity because it is a natural part of soil formation. When adding sand, it's important to use coarse builder's sand and mix it with the soil at a ratio of one part sand to two parts soil.

Perlite - a lightweight volcanic mineral, improves aeration and drainage. To incorporate perlite, mix it into the top layer of soil at a ratio of about 10-20% perlite to soil.

Vermiculite - enhances moisture retention and drainage. Use vermiculite by mixing it into the soil at a ratio of about 25% vermiculite to the soil for optimal results.

Compost - enhances soil structure and boosts microbial activity. To incorporate compost into your soil, evenly spread a layer of 2-3 inches over the garden bed and mix it into the top 6-8 inches of soil.

Coconut Coir and Peat Moss - lightens heavy soils and retains moisture while improving drainage. To use peat moss, mix it thoroughly into the soil at a ratio of about one-third peat moss to two-thirds soil.

Leaf Mold - improves soil aeration and drainage. For best results, apply a 2-inch layer of leaf mold on top of the soil and work it into the upper 4-6 inches.

Create A Rain Garden

Creating a rain garden is a great way to utilize a space that has a low spot by amending the soil and then also choosing plants that do well with standing water and will thrive regardless of rainfall. This works particularly well for landscapes but not so well for vegetable gardens. Choosing plants that are well-suited to your specific soil type can make a significant difference. Additionally, incorporating deep-rooted plants into your garden can greatly benefit soil structure. Deep-rooted plants, such as grasses and certain perennials, help to break up compacted soil layers, creating channels for water to flow through more easily. Their roots also add organic matter deep into the soil profile, which improves aeration and drainage over time. By carefully selecting plants that match your soil conditions and incorporating those with deep root systems, you can naturally enhance soil drainage and promote a healthier garden ecosystem.

French Drains

If you are still experiencing issues even after amending the soil and introducing water-tolerant plants, there are bigger steps you can take. Installing drainage systems can further improve soil drainage in problematic areas. French drains, for instance, are highly effective. A French drain is a trench filled with gravel and a perforated pipe that redirects excess water away from garden beds. To install a French drain, dig a trench along the area where water tends to pool, line it with landscape fabric, add gravel, place the perforated pipe, and cover it with more gravel and soil. Another solution is dry wells, which are underground structures that collect and slowly release excess water. To create a dry well, dig a large hole, fill it with gravel or a manufactured dry well unit, and connect it to drainage pipes. These more drastic steps, combined with the above steps, are sure to solve the issue.

Focusing on the health of your soil is one of the best things you can do for your overall garden health. Poor drainage causes a whole host of problems and can be remedied with a little hard work. Whether you’re trying to improve your landscape, your lawn, or your vegetable garden, there are solutions to your problem! Care for the earth, and the earth will care for you.