Your lawn could have brown spots for a variety of reasons—fungus, excessive thatch, and poor soil quality, to name a few. We’ll show you how to identify, repair, and prevent brown spots.
No one wants unsightly brown spots taking over their once-green stretch of lush, green lawn. But in order to solve this problem, you have to know exactly what you’re dealing with. There are multiple causes of brown spots, from poor soil quality to dog urine and over-fertilization. But don’t fret. This Old House will show you how to identify the brown spots in your grass, repair them, and prevent them.
What Causes Brown Spots in Grass?
Determine the cause of brown patches before treating them. Brown patches have several causes and need various treatments.
Grubs are plump, white beetle larvae that can do serious underground damage by eating roots. Their feeding habits can lead to uniform, sponge-like brown spots in your grass. There are several natural at-home remedies for treating grubs, like introducing beneficial nematodes or milky spore. Luckily, lawn care companies like TruGreen offer grub control, so you don’t have to do any guesswork.
Brown patch disease
Rhizoctonia causes brown patches. In hot, humid conditions, this disease develops brown grass patches.
Brown patch leaves uneven yellowish-brown circular patches in your lawn with a smoke ring border. The smoke ring border vegetation usually thins. However, the ring’s grass occasionally dies. Thin grass recovers without pesticides.
There are a variety of reasons your lawn may develop Brown patch, including high heat and humidity, excessive nitrogen, moisture, poor soil damage, too much thatch, and compacted soil. In some cases, you can’t prevent your lawn from developing Brown thatch—after all, you can’t control the weather. But you can take some steps to make it less likely:
- Apply fungicide: Some lawns require pesticides to fight brown patch, but most do not. Pros should handle this. Fungicides work at various periods. Some improve in 24 hours.
- Water properly: Water your lawn before 10 a.m. or between 4 and 6 p.m. to prevent brown spot from excessive wetness. Wet grass all night makes it more sensitive to disease and pests.
- Fertilize carefully: Too much nitrogen can lead to Brown patch. Try to avoid fertilizing your lawn when it’s hot and humid out, and select a fertilizer with a suitable NPK value. NPK refers to the proportions of nitrogen, phosphorus, and potassium in the fertilizer. You can ask your local gardening store about which fertilizer may be best for your lawn.
- Improve air circulation in your soil: Aerating and dethatching will reduce humidity, making it less likely that Brown patch will develop. Aerating is done using a core aerator or spike aerator, either pulling many little plugs or “cores” of soil out of the ground, or perforating it with many small holes. Dethatching, done with a dethatching rake, removes a layer of organic material that can smother grass. When you aerate and dethatch, you allow the grassroots to access the water, air, and nutrients they need more easily.
Thatch is the accumulation of dead and decomposing organic material nestled between grass blades and the root system. A little thatch can be a good thing, but a layer over ½ inch thick can choke the grass by preventing the flow of air, water, and nutrients and make your lawn more susceptible to pests and diseases.
Dethatching or aerating your grass fixes this. Your local garden shop rents or sells dethatching rakes to break up the coating. Check your grass type options.
Aerating your grass requires drilling small holes into the soil to allow it breathe. Most people buy or rent core aerators. This aerator eliminates microscopic soil plugs to let nutrients, water, and air into your soil.
If your mower blades are dull, they tan tear up your grass instead of cutting it cleanly. Shredded, damaged grass will die, and can cause brown spots. To avoid this, sharpen your mower blades in spring and fall.
Scalping is another issue. Even if your mower blades are sharp, you can do some damage—cutting your grass too short can create brown spots in your lawn. Raise your mower blades and be sure you’re only cutting a third of the grass blades at a time.
Too much fertilizer
Excess nitrogen causes brown patches. Do not fertilize too frequently or on hot days.
Poor soil quality
Poor soil quality can lead to brown, bare patches. Try pushing a long-head screwdriver six inches into your soil. If you meet too much resistance, try aerating and covering the area with top-dressing to add beneficial organic matter.
Combat soil erosion by aerating—this will increase water absorption and help your grass from drying out.
Pet urine burns
Urine from animals like dogs can create brown spots in your lawn, since it’s high in nitrogen. These brown spots have brown centers surrounded by dark rings. The best way to resolve this is by raking up as much of the patchy areas as possible and covering the areas with topsoil, then spreading some grass seeds. Water the area daily for two weeks to promote growth.
Dormant grass becomes brown. Winter dormancy affects warm-season and certain cool-season grasses. Some areas of your transition zone lawn may brown before others.
What causes dead patches of grass?
Watering too Little (or too Much!)
Overwatering and underwatering may create brown or dead grass. Underwatering causes grass to die when roots don’t get enough moisture.
Will dead patchy grass grow back?
fresh sod may start a fresh landscape, but dead grass cannot be revived. Your lawn needs fresh seed or sod if it has brown, barren, or thinning parts.
What are the round dead patches in my lawn?
Ophiosphaerella korrae, a soil-borne fungal, causes “frog-eye” illness. Fungi invade grass roots and crowns, generating tiny, dark brown lesions. These infections may grow into enormous circular dead grass areas.
How do I fix dead or bare spots in my lawn?
Repairing Bare Spots
- First, excavate. Remove dead grass first
- Mix topsoil. Compost or topsoil improves soil quality and helps fresh sod or grass seed grow.
- Step 3: Rake and Tamp.
- Step 4: Apply the Lawn Product.
- Step 5: Water the Area Well.
How do you treat brown patch lawn disease?
Improved grass air circulation lowers humidity, which favors the fungus and cures many brown patch instances. Aerating and dethatching the grass yearly is preferable.
How do you cure dead grass?
How to revive dead grass
- Take stock. Check your grass’s dormancy.
- Prepare your site.
- Eliminate excess thatch.
- Aerate by tilling the soil.
- Fertilize the soul after testing.
- Plant new sod or seed.
- Roll the sod.
- After-care process.