Clay soil can make lawn care maintenance more difficult especially in wet, colder climates like the Pacific Northwest. Much of the soil found in northwest Washington is composed of clay or sandy loam due to the geological formation of the area. Before we jump into lawn care techniques for homeowners with clay soil, it’s important to understand that soil is very different from dirt. Healthy soil is critical to a healthy ecosystem.
Soil is biologically active; it’s home to multiple ecosystems of microorganisms that support vegetation growth. It’s composed of both biotic (organic matter of once living organisms like plants and insects) and abiotic (non-living matter like air and mineral deposits) materials that form its support structure.
What is soil structure?
Put simply, soil structure is defined by the composition of materials (aggregates) and how they’re assembled. Good soil structures have a balance of soil, water and air that provide nutrients to the microorganisms that support vegetation growth. Ideal soil structure is composed of 45% minerals (abiotic materials), 5% organisms (biotic materials), 25% air and 25% water; 50% pores and 50% solids. Soils that do not have this balance will require soil amendments and increased maintenance to achieve healthy lawns and gardens.
Soil compositions are formed by 5 factors: climate, organisms, relief, parent material and time.
- Climate. Temperature and precipitation rate influence the rate of which parent materials decompose. Humans and their foot traffic fall into the climate factor.
- Organisms. The type of plants and animals that inhabit an area affect the composition of the soil and the microorganisms that can be found in the soil.
- Relief. The geographical formations of land determine the depth of soil and how much sunlight, rain and wind it is subjected to.
- Parent Material. The physical or chemical weathering of the historic geography determines the parent material of the soil. The composition and transportation of the material (water, wind, glacier, etc.) determines the parent material of a soil.
- Time. Time and climate affect the nature of the soil composition.
Because of Whatcom County’s unique geography, volcanic ash and glaciated till have resulted in soil characteristics that are largely composed of clay and sandy loam. Soil with heavy clay characteristics does not drain well which poses a problem to homeowners in the Pacific Northwest. The over saturation of clay soil causes runoff and cuts off air flow to the roots of grass. So, homeowners in Western Washington who want healthy looking lawns, should invest in the following lawn care techniques to improve their clay soil.
Aerating the Lawn.
Given that all living things need oxygen it makes sense that 25% of the ideal soil structure is air. Similar to water, ecosystems within the soil need room for cellular respiration. Microorganisms release and absorb nitrogen, carbon dioxide and oxygen gasses in various phases. Airflow allows these nutrients to reach the roots, strengthening the health of grass.
Stay Off My Lawn!
After a Pacific Northwest winter, soils rich in clay can become oversaturated in early spring, stifling air flow to grass roots. You’ll notice water pooling on top of grass.
Have you ever seen a sign telling people to “stay off the lawn!”? The impetus for the sign isn’t necessarily because the sign holder wants to be a grouch. It’s to protect the health of the grass by preventing the soil from becoming too compact. When water sits on top of grass and people or pets slosh through it, they can potentially damage the grass and cause muddy spots on the lawn. During long wet periods of time, it’s best to stick to walk ways to prevent compacting the soil and damaging the grass.
Carl’s Mower & Saw recommends aerating lawns with heavy clay characteristics twice a year: spring and fall. Aeration is the process of making evenly spaced perforations in the soil to optimize airflow. An aerator pulls up small plugs of soil and grass, helping to thin overly thick root systems.
Before you rent an aerator, it’s important to time the process when the soil is moist but not wet. If you aerate when the soil is saturated, the water will shift deeper into the soil— drowning the roots by preventing airflow. It’s ok to aerate soil when the ground is dry and hard, it’s just more difficult for the operator as moisture makes the process easier.
Aerating not only improves airflow to root systems but it also gives soil the ability to store water more efficiently. Rainfall gets absorbed more deeply and there’s less stormwater runoff, it can help save homeowners from having to water their lawns during the height of summer. Aerating improves the overall health and appearance of grass. Learn more about the benefits of aerating in our YouTube video.
At Carl’s Mower & Saw, you can rent or purchase outdoor power equipment to aerate your lawn. For smaller lawns we recommend using the Stihl Yard Boss or the Honda FG110 rototiller. Both are compact, versatile pieces of equipment that simply require a change in the appropriate implements.
For homeowners and contractors who manage larger lawns, we recommend a BCS tractor with the aerator attachment or a Ryan Aerator. Because it’s only necessary to aerate up to two times a year, renting an aerator can be more cost effective for homeowners.
Dethatching.
Thatch is what it sounds like: A build up of dried grasses and debris. It accumulates on top of lawns covering the base of grass where it meets the soil. A half-an-inch of thatch is good for the health of soil and lawns because it serves as a compost, feeding nutrients to the soil. But, over time thatch builds up and compacts making it difficult for the soil to get water, light and air.
Thick thatch is an appealing place for insects to nest which can lead to infestations. It can trap water and cause disease. And, because thatch prevents water from fully penetrating the soil, it encourages shallow root growth which weakens the roots and makes them susceptible to rot and fungus.
Remember, ideal soil structure needs 25% air and 25% water to thrive. To support soil health, it’s important to dethatch your lawn one to two times a year, depending on how quickly thatch accumulates in your location. The process pulls tufts of thatch away from the soil so it can easily be picked up and composted.
For homeowners and contractors who manage bigger lawns, BCS and Husqvarna make efficient equipment to remove thatch. If you have a smaller lawn, a dethatching rake can work. Or, Carl’s Mower & Saw recommends using the Stihl Yard Boss or Honda FG110 with the dethatcher attachment.
Both the Yard Boss and the FG110 can support a number of lawn and garden operations. The Yard Boss is even great for sweeping snow off walkways and driveways.
Seed & Fertilize
Remember those muddy patches that appeared after someone went running through your overly saturated lawn last winter? It’s time to rent a slicer and get a few bags of seed! Don’t know what kind of seed you need? We answer that question here.
If you live in the Pacific Northwest and your soil is rich with clay, your lawn is susceptible to damage. After you’ve aerated and dethatched, the next best step is to over seed and slice it deeply into the lawn.
Spreading down seed and slicing it into the ground will help to ensure that you’re maximizing the potential for germination. The goal is to set yourself up with a system that encourages deep, healthy root growth and gives you a thick blanket of grass. Learn more about how aerating and slicing supports lawn health in this video.
Soils rich with clay will need to be fertilized with nitrogen-rich material like manure and compost to help improve the health of grass and encourage the roots to grow more deeply. It’s best to fertilize after aerating, dethatching and seeding, to help work the fertilizer more deeply into the soil to give your seeds a jump start on growth.
Keep in mind that clay has a longer retention rate, so a little fertilizer can go a long way. The same can be said for chemical use, as chemicals are retained for longer periods in clay-based soils.
After you’ve taken steps to get your lawn ready for spring, check out more lawn care tips that include mower height recommendations, treating bugs, grubs and more.
Carl’s Mower & Saw, Your Experts in Outdoor Power Equipment
When it comes to year-round lawn care, Carl’s Mower & Saw has you covered. From dethatchers to aerators, Honda Generators, Gravely Mowers, Stihl Kombi Systems, Husqvarna Automowers and much more. We service what we sell and we rent equipment, too.
Stop in and consult with one of our experts about the best lawn and landscaping equipment for your property.
Learn more online by visiting www.CarlsMower.com or give us a call 360-384-0799.
