Although “white grass” is a bit of a broad statement, there are actually only a few reasons it may occur.
The most common cause of grass turning white is fungal growth, which includes all types of molds. Weed control chemicals can bleach grass white. Nitrogen-rich fertilizers can also cause the grass to whiten. Grass that’s sunburnt usually turns a light shade of brown but can appear white in extreme cases.
There is definitely no single solution that will solve these possible causes, which is why it’s so important that you first understand what you’re dealing with before taking action.
This article will help you identify and treat the problem at hand and get your lawn from white to green within a few weeks or less.
Fungus On The Lawn
Gray Leaf Spot
A fungal disease specific to grass, gray leaf spot thrives in warm, humid weather like that of Florida.
It almost looks like sun burnt grass, starting out tiny on the blades of the grass but soon spreading throughout the whole lawn in brown circular patches.
This is quite common in many gardens, affecting more than just grass. Powdery mildew blocks out the sun and reduces growth and reproduction rates in the grass. This fungus spreads through the air with the help of wind. It can also lay dormant for months before springing up again and taking over.
On close inspection, you should be able to see tiny circles of mold formations on the blades of grass. If it’s not treated quickly, it will completely cover the grass before long, causing it to turn brown and die out.
Pink Snow Mold
During winter, blankets of snow cover grass, which cause warmth and moisture to be trapped underneath. The snow causes somewhat of a greenhouse effect, creating an isolated climate, ideal conditions for fungal growth.
If your lawn is moldy after a heavy snowfall, it’s likely pink snow mold.
Hot and humid conditions allow this fungus to grow like any other. Winter grass is especially susceptible to this type of fungus during times of drought stress.
If you see light green patches that mature to a reddish brown under high heat, it could be Fusarium blight.
Lawn Fungus Treatment
If you’re convinced that a fungal infection is the cause of your grass whitening, here’s a basic guideline for how to treat your lawn.
There are two main types of fungicides to apply, contact and systemic fungicides. Check the labels or ask the salesperson if you’re unsure.
This type of fungicide covers the grass blades to protect them from the fungus spreading. This layer of protection makes sure that the fungus doesn’t get into the plant and kill it. Although it’s more of a preventative fungicide, it still helps when trying to eliminate fungus quicker.
These fungicides penetrate and work their way through the grass, as long as the grass is still alive and growing. These are the fungicides that treat existing fungal problems.
Remove dead grass
Once the fungus has killed a section of grass, you can’t just bring it back to life. Remove the grass with a metal rake until you’ve exposed the soil underneath. If you have any unwanted moss growing, read more about it in this article.
Plant your grass seeds in the bare area you’ve created.
Feed the seedlings
Feed the young sprouts with fertilizer for young plant life, not the normal fertilizer for fully grown grass.
Apply a thin layer of topsoil
You can apply a very thin layer of topsoil over the seedlings to nourish and protect them in their first few days of growth. Not more than a half inch, though otherwise, the grass might not make it all the way through.
Water the seedlings
Water the freshly planted seeds late in the morning every day until you see them sprout. Only water the area where you’ve planted the seeds. Water the rest of the grass once per week, as usual.
Lawn Fungus Prevention
Once you have your lawn free of fungus, it’s easier to keep it away than dealing with it again. Here are a few preventative measures to keep fungus away.
- Don’t over water. An established lawn only needs about 1 to 2 inches of water per week. Get yourself a rain gauge to monitor the rain and only water the lawn if it gets less than 1 inch of rainfall per week.
- Water once a week so that the grass and roots can breathe a bit.
- The mornings are the best time to water because the sun will help the moisture evaporate before nightfall.
- Feed your lawn with fertilizers to keep it strong and healthy. That way, it will be more resistant to being overrun by mold.
- Keeping the lawn at an optimal height will also help prevent mold. Most lawns do well at a 2 to 3 inch height. So you could mow it down to around 2 inches every week to maintain the perfect length.
- Increase the amount of sunlight the grass gets. Trim nearby bushes and trees or remove shade nets. Some people opt to remove certain trees to allow more sunlight onto the lawn.
- Don’t use fertilizer with too much Nitrogen as it will promote fungal growth.
Flatten Out The Ground
If your grass is turning white in areas where the ground is sunken, it could be because those areas hold water so well. The airflow is also less in ditches, adding to the problem. If you have any dips in your lawn, even them out with some topping soil so that water can run through the area easier.
Not Enough Aeration On Lawn
Stagnant air causes moldy problems. It may sound overdramatic, but you may need to change the type of fencing or walling you have around your lawn to increase the airflow in the area.
Just don’t increase the airflow before you’ve treated the lawn with fungicides or the wind will spread the fungus around even more. Once the fungicides have been applied, we should protect the rest of the grass against new infections. The new airflow could eliminate fungal problems altogether.
Weed Control Chemicals
There are many weed control products that bleach plants in order to kill them. Once whitened, the plant cannot absorb the minerals it needs to survive. So, if you’ve used a weed killer in the area, chances are you might have bleached your grass by mistake.
You will simply have to remove the grass and replant it in that area, as explained in the Lawn Fungus Treatment section at the beginning of the article. Just skip the fungicide treatment.
Over-fertilizing can cause white streaks on the grass blades. There are some salts in fertilizers that can dry out grass, which is why they damage grass easily if overdone.
Fertilizer Burn Prevention
- Follow the instructions on the label of any fertilizer and rather apply slightly less than required rather than slightly more.
- It’s best to use slow-release organic fertilizers to minimize the risk of fertilizer burn.
- Don’t fertilize your lawn while it’s wet. Rather, fertilize one or two days before the weekly watering.
- Composting is a safer way to fertilize grass with less risk of fertilizer burn.
- Avoid composting and fertilizing during a drought season, as the soil will be too dry to distribute the nutrients accordingly.
Fungal outbreaks in your grass are the most likely cause of whitening grass. Treat the lawn with a fungicide to stop the spread and protect uninfected areas. Remove the dead grass and replant seedlings in the dead zone. Feed the seedlings with fertilizer specific to new grass, usually high in nitrogen. Don’t get this fertilizer on the adult grass or you may assist the fungal growth. Water the newly planted grass every day until the grass sprouts and fills in the area.
If you don’t have a fungal problem, you might have over-fertilized, causing fertilizer burn. You may see white streaks in the blades of grass. To avoid this, always follow the instructions on the fertilizer label, don’t fertilize during a drought, don’t fertilize wet grass, and opt for fertilizers with lower nitrogen levels once the grass is fully grown.
Grass will turn white if you’ve used weed killers in the area that bleach plants to kill them.
Another possibility is that your lawn simply isn’t getting enough sun. You may need to trim away some bushes and trees to allow more sun to get into your garden.
Don’t water an established lawn every day. Water your lawn 1 to 2 inches once per week instead.