As tempting as it may be to remove the debris that rain has swept in, you should not dethatch your lawn after rain. In fact, it can damage your lawn and lead to further compaction!
Dethatching After It Rains: Why You Shouldn’t Do It
Here are the reasons why dethatching your lawn after rain is harmful:
It Damages Grass Roots
The roots of the grass are especially vulnerable after rain, or when the ground is wet. As the roots are the support system for the grass and help to hold it up, any damage affects new growth as well.
Dethatching after rain can damage the root structures or pull out the roots. What’s worse, you might not know straight away because the damage is underground!
Too Much Thatch Removal
A thin layer of thatch is needed for your lawn. Too much—or too little—is not good for the health of your lawn.
If you remove too much thatch, your lawn loses its insulating properties that hold moisture in the soil.
Dethatching a lawn after rain means that there will be too much moisture present, which will make the dethatcher pull up your lawn in clumps.
Creates Soil Compaction
Compaction is the result of weight pushing down on the soil.
Wet thatch and organic matter on top of the grass creates a load that is too heavy for the lawn to bear, and can damage it as a result.
This is especially true if you decide to dethatch when it’s wet and move the weight around even further.
In turn, compaction can lead to drainage issues and problems with root growth.
Can Create Turfgrass Scalping
This is exactly as it sounds: Turfgrass scalping is what happens when you either cut your grass too low, or remove too much thatch! The stems of your grass, and the soil below, become exposed.
This prevents your grass from being able to photosynthesize correctly, and therefore it won’t grow. Trying to dethatch your lawn while wet increases the probability of this happening.
May Cause Clogged Dethatcher
If you try to dethatch your lawn while it's wet, you may cause the machine to clog. This is because the thatch gets caught in the machine.
Things like mud are also more likely to be present when the grass is wet, leading to further clogging. This can also lead to the grass being ripped out.
When is the Best Time to Dethatch?
It’s not advisable to dethatch a wet lawn, but you still need to dethatch it at the best time. So, when is the best time to dethatch?
Ideally, you should dethatch the lawn when the grass is in its active growth phase to allow them to recover quickly from the process.
Warm Season Grasses
If you live in a warm region, you’re most likely going to have warm season grasses like St. Augustine grass. The best time to dethatch warm season grasses is during late spring and early summer.
Cool Season Grasses
Like with warm season grasses, if you live in a cold region, you’re likely to have cold season grasses. It’s best to dethatch these in early fall.
When to Dethatch
The best time to dethatch your lawn is at a time when the grass and soil are a little moist and actively growing. Try to avoid dethatching during temperature extremes.
Don’t dethatch your lawn after it has rained or it’s been watered. As above, you should dethatch your lawn depending on whether you have warm or cold season grass.
Generally speaking, you should dethatch your lawn every 1-2 years.
An Alternative to Dethatching
Another process that works is power raking. Power raking involves using knives or blades to break up the thatch.
This is a gentler process than dethatching, and works well if the thatch layer is not too thick.
Why Dethatching Is Important
Dethatching is important. Excessive thatch build-up can harbor matter that you don't want in your garden, such as harmful bugs and diseases. This is typically worse, the thicker the layer of thatch gets. Too much thatch can also prevent water reaching the roots of the grass!
Ideally, you should keep the thatch layer to within a quarter of an inch or maximum half an inch. You should use either a dethatching machine or a dethatching rake to dethatch, not a regular rake and not a dethatching blade mower attachment either, because they're too weak.
If the thatch grows above one inch, you may end up needing to fully renovate your lawn as thatch can be unmanageable at that level.
In saying that, some thatch is important for the health of your lawn because it acts as a kind of mulch, and there are both pros and cons to dethatching. Here are some of the reasons why an appropriate level of thatch is beneficial for your lawn:
Ensures Healthy Grass Root Growth
If the thatch is not too thick, everything that the grass needs (water, nutrients, and air) is able to get through the soil level to the roots of the grass.
Thatch also acts as a layer of protection for the grass, reducing any possible damage from foot traffic.
Thatch acts as a filter that collects rainwater. It removes impurities and reduces groundwater contamination.
It does so by straining out these impurities, so that only the best water reaches the roots.
Ensures Fertilizer Penetration
With the improved drainage that thatching provides, the fertilizer can reach the soil more easily.
This improves the grass’s ability to absorb the fertilizer, resulting in better and faster growing grass.
Promotes Sufficient Nutrients for the Lawn
Thatching provides nutrients for the soil, as earthworms break down the organic matter in the thatch.
Secondly, the grass clippings that make up a large percentage of thatch contain nitrogen, phosphorus, and potassium—the same nutrients that are in fertilizer!
Better Lawn Appearance
Thatch improves the appearance of your lawn due to increased oxygen and water getting through, and fewer weeds and diseases.
Additionally, because thatch adds a protective layer to your grass, your grass is less likely to be damaged by foot traffic or animals– resulting in a better looking lawn.
Thin layers of thatch can actually allow for air and light to penetrate the roots of the grass—aspects that are fundamental for the health of your lawn.
Increased airflow also helps your grass to absorb nutrients and avoids the harboring of diseases.
Improves Overall Lawn Health
Thatching improves the overall health of the lawn by improving the quality of the soil. Good bacteria eat the thatch and break it down, improving soil quality.
After you've finished dethatching, you can either compost the thatch or throw it away.
Dethatching After It Rains: The Verdict
Thatch is important for the health of your lawn—but only in small amounts. You should dethatch your lawn when needed to provide health benefits to the soil and roots!
It’s important that you don’t dethatch your lawn when the ground is wet, or you’ll risk damaging it in both the short and long term.
The best time to dethatch your lawn is when it is actively growing based on the grass type, and when the ground is a little moist (but not too much). Also make sure to avoid dethatching during temperature extremes!