When Washington summer rolls in with its warm days and long evenings, we all want to spend more time outside. But while you’re soaking in the sunshine, your lawn could be suffering in silence. Unbeknownst to many, there are some lawn care mistakes that can ruin even the healthiest grass during the hottest months of the year. If you’ve ever wondered why your yard doesn’t look as lush in August as it did in May, this is for you.

Overwatering vs. Underwatering

During the summer heat, it’s easy to assume “the wetter the better”, but overwatering is actually one of the most common lawn care mistakes you can make.

How Much Water Does Your Lawn Really Need?

Most lawns need about 1 to 1.5 inches of water per week, whether it comes from rain or irrigation. That doesn’t mean watering every day. Instead, water deeply and less frequently to encourage deeper root growth.

Symptoms of Overwatering and Underwatering

If you’re dealing with mushy soil, yellowing grass, increased weeds, and lawn disease, you’re probably getting your lawn way too wet. On the other side of the spectrum, if your grass is crispy, the lawn is balding, or the soil is dry and cracked, these are all pretty good signs that your yard is thirsty. To hit that perfect balance of moisture, try to water early in the morning, ideally before 9 a.m. This allows moisture to soak in before it evaporates and helps prevent fungal issues.

Mowing Your Lawn

Mowing seems simple, but beware; doing it wrong can literally tear the grass apart. There’s a lot of things that can go wrong when mowing: dull mower blades can shred instead of cutting, mowing when the grass is wet compacts the soil and spreads disease, and cutting it too short exposes roots to the summer heat. So how do you mow the right way?

The 1/3 Rule: Don’t Cut Too Much

Never cut more than 1/3 of the blade height at once. Cutting too low stresses the grass, weakens its root system, and invites weeds and fungal diseases.

Should You Mow Before or After Treatments?

In most cases, mow your lawn before fertilizing or applying weed treatments to help the product reach the soil. Just avoid mowing right after, since the treatments need time to absorb.

Feeding Your Lawn

Fertilizing your lawn can help, but only if you do it right. Blindly fertilizing your lawn is like seasoning a soup you don’t know the base of; there’s no way of knowing whether you need cheese or miso, and the wrong flavors will ruin your dinner. 

Summer Fertilizing Tips

In order to get the best bang for your buck when it comes to fertilizing your yard, here’s what we recommend: 

  • Skip high-nitrogen fertilizers during peak summer heat. They can burn the grass.
  • If needed, use a slow-release fertilizer designed for hot weather or turf recovery.
  • Always get your soil tested first so you’re not just guessing.
Lawn Disease

Summer is prime time for lawn diseases, especially when heat meets humidity. Brown patch, dollar spot, and summer patch all love the hot, heady Washington summer conditions, and ignoring them certainly won’t make them go away. So what should you look for? 

How to Identify Lawn Fungus

The names of each malady are the first clue to what you should keep an eye out for, but to be really precise, brown patch is characterized by circular brown spots that spread quickly, dollar spot looks like bleached looking silver-dollar-sized patches, and summer patch is patches of wilting grass in sunny spots. 

What to Do When You Find It

To combat these diseases, your first step is to act quickly. Stop mowing affected areas until the fungus is under control to prevent spreading spores. Fungicide treatments may help in severe cases, but they work best when combined with good cultural practices like aeration, soil testing, and removing excess thatch. A healthy, well-maintained lawn is your best defense against most lawn problems.

Tip: Aerate your lawn and improve drainage to fight back against fungal outbreaks. You should also try to avoid watering at night because damp conditions invite disease.

Don’t Let Weeds Take Over

Weeds love stressed lawns. If you ignore them, they’ll quickly take control.

How to Deal with Summer’s Most Aggressive Lawn Weeds

If you’re seeing crabgrass, dandelions, or clover appearing in your lawn, don’t despair. These intruders aren’t fatal if you take care of them quickly, but definitely shouldn’t be ignored. Use spot treatments or natural methods like vinegar or corn gluten meal to manage growth. And remember: A thick, healthy lawn is your best defense against any and all ailments. 

Adjusting Your Irrigation System

Watering your lawn like it’s springtime won’t cut it during a Washington summer. To adjust for hot weather, make sure that the water is being evenly distributed. If needed, adjust your sprinkler heads so they spray every area, and never too heavily in one spot. Don’t water daily, water deeply 2-3 times a week. If it’s within your budget, a smart watering system is a great way to keep your lawn perfectly watered on schedule all summer long. 

Compacted Soil and Thatch Buildup

Healthy soil = healthy grass. But when soil gets compacted or covered in thatch, roots can’t breathe. If you’re not sure about the state of your soil, you can try pushing a screwdriver into the ground. If it’s tough to get in, your soil might be too tight. If that is the case, your best bet to fix it is aeration (preferably in early fall or late spring) and dethatching.

PNW-Specific Summer Lawn Tips

In Washington, unique climate factors come into play. Some methods that are great in steadier areas aren’t in our home climate’s fluctuation. To keep your pacific northwest lawn in tip-top shape even during dry spells, here’s what we recommend:

  • Choose drought-tolerant grasses like fine fescue or perennial ryegrass.
  • Mulch mow to keep moisture in.
  • Use drip irrigation in tight spaces or for sloped lawns.
Final Thoughts

A healthy lawn doesn’t happen by accident. It takes consistency, a little planning, and knowing what to avoid, especially during the dog days of summer. Now that you know the biggest summer lawn care mistakes, you’re better equipped to avoid them and give your grass the best shot at staying green, thick, and healthy.

Need a Hand? Let’s Build the Lawn You’ve Been Dreaming About

At True Design Landscape, we don’t just mow, we create outdoor spaces that reflect your style, match your needs, and thrive year-round in the Pacific Northwest. From turf installation and irrigation upgrades to full landscape design, we’re here to help your yard reach its full potential.

Your dream yard is waiting. We’ll help you bring it to life.