Don’t despair if you’ve recently seen brown patches on your lawn. In this article, we’ll help you get to the root of the problem and prescribe a straightforward solution that can help your grass return to its former glory.
Common causes of brown spots and how to fix them
Before you can treat the brown patches in your lawn, you need to accurately diagnose the source of the problem. Most brown spot problems are caused by a fungus, environmental or maintenance issues, or insects.
Let’s explore the problems that fall within each category and their common remedies.
1. Fungal
Numerous fungal diseases can attack your lawn and cause it to turn brown. Fungi thrive in humid weather and can be a problem when water does not evaporate from the grass leaves or when the soil does not have good airflow.
Here are a few of the most common:
- Anthracnose
- Brown patch fungus
- Dollar spot
- Fairy ring
- Gray leaf spot
- Large patch
- Leaf spot
- Pythium blight/pythium root rot
- Rust
- Spring dead spot
- Summer patch
- Take-all root rot
Fungal diseases can be very difficult for homeowners to identify. The easiest way to confirm a diagnosis is to call an expert at your local Cooperative Extension office. Ask if you can send them a photo or bring in a sample of the grass blades.
Once you have identified the lawn disease, check out this report from the UGA Extension Office for detailed management recommendations. The North Carolina State Extension website has articles on how to manage fungal diseases, as well.
General advice for almost any fungal disease is similar:
- Balance your soil’s pH and nutrient levels.
(You may not want to fertilize with an active fungus. Ask your Cooperative Extension agent for advice on the best practice for your lawn’s situation.)
- If your soil is compact, aerate.
- Dethatch once thatch level reaches three-fourths of an inch to allow for more airflow.
- Irrigate with 1 inch of water once per week. Don’t run your sprinklers after 9 a.m.
- Use fungicides as a last resort.
- Overseed areas where the grass has died.
Note: With all of these recommendations, timing is important. Ask an expert to ensure you’re doing the right thing at the right time.
2. Environmental or maintenance-related
- Improper mowing practices
Your lawn may be more susceptible to disease if you mow too short, cut off more than one-third of the blade at a time, or mow with a dull mower blade.
Solution: Mow to the highest recommended height for your grass type. Don’t cut more than one-third of the grass blade per mowing, and sharpen your blade two to three times per year (unless you have a very long growing season, then you will want to sharpen it more often).
How do you know when to sharpen the blades? Look at the blades of grass after you mow. If the blades have a clean cut, you’re good. If the edge is ragged, it’s time to sharpen your blades.
- Soil compaction or excess thatch
Compacted soil is detrimental to water and air circulation. Grass roots can’t grow as deep and water doesn’t drain as well, which can lead to diseases in the root system.
Thatch is a layer of material between the living grass and the soil. Under one-half inch or so is fine, but anything over that can be detrimental to the lawn. It prevents water and fertilizer from getting to the roots and can harbor fungi and insects.
Solution: Aerate once per year and dethatch the lawn once thatch buildup reaches one-half to three-fourths of an inch. Local home improvement rental centers usually rent both these machines.
- Excess fertilizer
If you inadvertently apply too much fertilizer to the lawn, it may burn your grass. The salts in the fertilizer, if overapplied, make it hard or impossible for the plant to take in water. The result is that the plant suffers from drought because it cannot uptake the water as it should.
Solution: Hose down the affected areas until the ground is saturated. This will help the excess fertilizer to move out of the roots. Then, apply one inch of water for the next three to four days (or up to a week) to rid the ground of the excess salts. Going forward, fertilize with slow-release nutrients, as these rarely cause burns, or apply less than the recommended amount of a quick-release fertilizer.
- Drought
Drought is a common problem. If your area is in a drought or has local watering restrictions, your grass may turn brown if it goes into a dormant state. You may think you have dead grass from the look of the lawn, but only in extreme conditions will the entire yard completely die. Dormancy is a self-protective state where the grass stops actively growing and turns brown.
Solution: To keep the crown of the grass hydrated, water weekly at one-fourth of an inch or every other week at one-half inch as a general rule. Check with your state’s Cooperative Extension office for local watering advice during drought conditions.
During a drought, mow less frequently and increase your mowing height to avoid putting additional stress on the lawn. Also, avoid walking on the lawn. When you do mow, leave the grass clippings on the lawn for additional moisture and root protection.
To keep your lawn green during periods of drought, consider grass paint. This is an easy, DIY solution for unattractive, brown grass.
- Dormancy
As we’ve mentioned above, dormant grasses stop growing and turn brown. Cool-season grasses go dormant in the summer while warm-season grasses go dormant over the winter. Once the temperatures change, the grasses green-up again and start growing.
Solution: None. Wait until the weather changes, or paint your lawn.
- Pets
Dog urine can cause brown spots in your lawn due to its nitrogen content and other compounds that may affect the soil’s pH.
Solution: After the dog urinates, use the hose to diffuse the nitrogen in the soil. Besides this, you may consider decreasing the nitrogen in your routine fertilizing program.
- Gasoline or chemical spill
If you have a substance spill on your lawn, it may kill the grass immediately.
Solution: If the chemical spill kills the grass, overseed at the appropriate time of year.
3. Insects
- Grubs
Grubs are a common cause of brown patches in the lawn.
Solution: Dig up a 12-inch square of grass to determine if you have grubs. (In severe infestations, you may be able to roll up the turf like a carpet since grubs sever the roots in two as they feed.) If there are more than 6 or so per foot, you may want to consider treatment. You can find conventional insecticides at your local home improvement store or contact an organic lawn care company that has experience using beneficial nematodes.
When treating grubs, timing is critical. The timing of your treatment depends on the type of grub you’re treating. Ask your lawn care pro or local Extension agent to help you determine when and how to treat.
Here are a few tips to prevent grub damage:
- Choose resistant grass species
Endophyte-enhanced fescue and ryegrass (both cool-season grasses) are better able to resist billbug grubs. If you live in a warm-season area, any grass that spreads aggressively (such as bermudagrass) recovers from grub damage more quickly and shows fewer signs of injury.
- Milky spore
Helps reduce Japanese beetle grubs, but is not effective for other beetle species.
- Encourage predatory species
Birds, ants, and wasps are natural grub predators.
- Warm-season grass
Warm-season grasses have an advantage over cool-season grasses in that most tolerate dry soils better. Grubs prefer moist soils, so dry soils may discourage them from setting up shop.
- Chinch Bugs
Chinch bugs affect both cool- and warm-season lawns. St. Augustinegrass is the most likely host in warm-season lawns. In northern areas, chinch bugs often feed on Kentucky bluegrass, perennial ryegrass, bentgrass, and red fescues. Chinch bugs cause patchy brown spots of dead grass in the lawn as they actively feed during the summer months.
Solution: In most cases, non-chemical strategies are effective. During hot, dry periods of the year, keeping your grass deeply watered once per week will usually deter chinch bugs from feasting on your lawn. Since chinch bugs feed on lawns with a thick layer of thatch, dethatching is another effective preventive control.
Insecticides are an option but are not necessary most of the time. One reason is that they will kill the chinch bugs’ main predator, the big-eyed bug. The controls mentioned above (watering and dethatching), are usually sufficient to prevent or treat any problems.
Get back your lush, green lawn
Unsightly brown patches are a detriment to a green, healthy lawn. First, diagnose the problem, use one of our recommended solutions, and practice good preventive lawn care going forward. Brown spots don’t have to be the bane of your existence. Most of these problems are relatively easy to treat and can be largely prevented by good lawn maintenance practices going forward.
If you’d rather have a professional set of eyes from the get-go, consider hiring a lawn care professional who can diagnose and treat your lawn’s brown patches with accuracy and efficiency.
Main Photo Credit: Harry Rose | Flickr | CC BY 2.0
