Why is my grass green on top but brown underneath? 5 common causes explained

Maintaining a healthy lawn requires vigilance, and a seemingly lush green surface can mask underlying issues. Upon closer inspection, you may discover brown, patchy undergrowth. Fortunately, several common causes can explain this phenomenon. Let’s look into five reasons why your grass might be green on top but brown underneath, along with solutions to achieve a uniformly verdant lawn.

1. Lack of Water:  This is a classic culprit. The green is a facade sustained by the meager moisture reserves clinging to the soil’s top layer. Those brown blades down below? Parched and thirsty.

• Solution: Deep watering is key. Aim for 1-1.5 inches of water per week, delivered in long, slow sessions to penetrate the root zone. Early morning watering is ideal to minimize evaporation.

2. Mowing Madness:  Scalping your lawn with overly aggressive mowing can weaken the grass and prevent sunlight from reaching the lower blades. This starves the undergrowth, leading to brownness.

• Solution: Raise your mower deck! Aim to remove only the top third of the grass blade. A higher mowing height shades the soil, retains moisture, and encourages thicker, healthier growth.

3. Thatch Threat: Thatch is the layer of dead grass and stems that accumulate at the base of your lawn. A thick thatch layer acts like a suffocating blanket, preventing water, air, and nutrients from reaching the roots.

• Solution: Dethatching with a rake or a dethatching machine can remove excess thatch buildup. Core aeration is another option, creating channels in the soil for improved air and water circulation.

4. Grubs and Other Lawn Loathers:  Grubs, the larvae of beetles, feast on grass roots, leaving brown patches in their wake. Other pests like chinchbugs can also wreak havoc on your lawn’s health.

• Solution: Inspect your lawn for signs of pests. If you discover an infestation, insecticidal treatments can help eradicate the problem and allow your grass to recover.

5. Shady Secrets:  Lawns simply need sunlight to thrive. Excessive shade from trees or buildings can prevent enough light from reaching the lower blades, leading to browning.

• Solution: Consider pruning tree branches to allow more sunlight to reach the lawn. In some cases, shade-tolerant grass varieties may be a better long-term solution.

By addressing the underlying cause, you can transform your two-toned lawn into a uniform green carpet. Remember, a healthy lawn requires consistent care. With proper watering, mowing practices, and vigilance against pests and shade issues, your lawn can continue to be the envy of the neighborhood.