Identify the Problem First
A dense, green home lawn doesn't need to be dethatched or aerated. In fact, dethatching or aerating a healthy lawn is a waste of both time and money. Plus, it will cause undue stress on the turf. Slicing through roots and severing stems sends the lawn into survival mode, drawing on extensive nutrient and water resources to recover. Always address any nutrient, disease, and weed problems before subjecting the lawn to dethatching or aerating.
Dethatching and aerating are hard-hitting lawn practices that work to remedy specific turf challenges. Let your lawn lead the way. If it has weak growth and a thin, patchy appearance, one of these techniques might help. If the lawn feels spongy underfoot and has a dull appearance, along with minimal growth, dethatching might be necessary.
Bottom line, dethatching and aerating are not annual maintenance practices; they address specific lawn problems.
rake-dethatching-47648d82
When excess living and dead roots, crowns, and shoots build up above the soil level, it is time to dethatch. A lawn with too much thatch feels spongy or springy when you walk across it and often shows signs of stress. The blades might take on a dull green color, and growth might slow. This is all because the layer of excess tissue is preventing water, nutrients, and oxygen from getting down into the root zone.
How to know if you need to dethatch: Use a spade to lift a thin wedge of turf. Measure the distinct layer of brown, spongy material above the soil and below the grass blades—this is the thatch. If that thatch layer is greater than ½ inch, it's time to dethatch the lawn. If it is less than ½ inch, soil microorganisms have the potential to break down the layer; monitor their progress by taking another measurement in about a month.
Best time to dethatch: Dethatch when the growing conditions are prime for growth. Early summer is the best time to dethatch warm-season grasses such as zoysiagrass and bermudagrass. Cool-season grasses, such as Kentucky bluegrass, should be dethatched in spring or fall.
After care tips: Be prepared to care well for turf after dethatching. Water regularly to promote regrowth. Fertilize minimally or with a slow-release fertilizer. Excessive fertilization leads to thatch development, and you could easily be right back where you started.
Aerating is somewhat effective at breaking down thatch, but it is not nearly as beneficial as dethatching. If the thatch layer is beyond ½ inch, dethatch the lawn; do not try to remedy the problem with aeration.
Mechanical lawn aerator
Andy Lyons
When to Aerate
Aeration combats soil compaction. Lawns that have been pummeled with construction or vehicle traffic benefit from aeration. Compacted soil has limited space for roots, water, and nutrients to move.
A core aerator removes 2- to 3-inch-long cores of soil from the lawn and drops the cores on the lawn. The newly made channels allow water, nutrients, and oxygen to more easily enter the root zone, giving new life to the turf and reinvigorating the microorganisms that are essential for healthy soil. Leave the cores on the turf surface where they'll return to the soil as they break down.
How to know if you need to aerate: When the soil is moist, try to push the blade of a knife into the soil with just the pressure of your thumb. If the knife moves into the ground, there is no need to aerate. If resistance stops the knife from moving, aeration might be helpful.
Best time to aerate: Aerate when the turfgrass is actively growing for fast recovery. Spring or fall is the best time to aerate cool-season grass. Aerate warm-season grass in early summer.
