NECROTIC RING SPOT TREATMENT
How to Control Necrotic Ring Spot without Chemicals
Necrotic Ring Spot (NRS) is one of the most frustrating lawn diseases for homeowners due to the abundance of misinformation surrounding its causes and treatments. Primarily, NRS is triggered by excessive watering over a long period of time (months) combined with the use of chemical fertilizers. This combination disrupts the balance of beneficial microbes in the soil, creating ideal conditions for the Necrotic Ring Spot fungus to thrive in low-oxygen environments.
If you notice Necrotic Ring Spot on your lawn, it’s an opportunity to address an underlying issue. The first step toward recovery is to reduce the watering, which is key to preventing further damage. Implementing the 1-2-3-2-1 lawn watering technique can help you manage your lawn’s moisture levels effectively.
The second step of rebuilding the soil’s microbial population is a much slower process and may take up to 2 years to fully rebuild. This process requires time and dedication, but it will lead to a healthier lawn in the long run. While spores of the Necrotic Ring Spot fungus are found in soils worldwide, areas like Colorado—where sprinkler systems are prevalent—can be particularly affected. Unlike natural weather patterns, which provide variability in moisture, irrigation systems can create conditions that promote NRS. By adjusting your watering practices and focusing on soil health, you’ll be well on your way to revitalizing your lawn.
Healthy soils are essential for maintaining a vibrant lawn, and one key component is the presence of beneficial microbes. These microbes help stabilize the soil’s microbiome, creating a competitive environment that keeps harmful organisms, such as necrotic ring spot fungi, in check. Without these beneficial microbes, the necrotic ring spot fungus can thrive unchecked, particularly in oversaturated soil, which promotes the rapid spread of its spores.
When a necrotic ring spot outbreak occurs in your lawn, managing it can be a daunting challenge. The recovery process is lengthy, often taking nine months or more. This extended timeline is primarily due to the need to rebuild soil health, which can take anywhere from six months to two years. Without a fully restored microbial ecosystem, the necrotic ring spot fungus will continue to pose a threat. Therefore, having the patience and commitment to this recovery process is crucial for reviving your lawn from necrotic ring spot.
See below for the step by step process to treat a necrotic ring spot infested lawn.
How to Cure Necrotic Ring Spot in Grass
Why Applying a Fungicide to a Necrotic Ring Spot Infested Lawn Is a Bad Idea!
When dealing with Necrotic Ring Spot in your lawn, it’s crucial to avoid fungicides. While they do target harmful microorganisms, they also destroy the beneficial microbes. Rebuilding the beneficial microbial population is essential to reclaiming the lawn from the Necrotic Ring Spot fungus. The best approach to curing Necrotic Ring Spot is to foster a thriving, diverse community of beneficial microorganisms. Once the soil and the microbiome is balanced, the microbes will naturally combat the Necrotic Ring Spot fungus spores.
The main reason a lawn becomes overrun by Necrotic Ring Spot is because the excessive water caused by the overwatering replaced the air in the soil, and without air the majority of the microbes die. The Necrotic Ring Spot fungus thrive in an anerobic environment which is why they were not also killed by the excessive lawn watering.
Important Note: It’s essential to understand that Necrotic Ring Spot fungus spores are always present in the soil and are not spread by core aeration, lawn mowing, or other lawn maintenance activities. These spores are everywhere; they only pose a threat when excessive overwatering occurs for extended periods. By adjusting your watering habits to follow the 1-2-3-2-1 lawn watering technique and promoting healthy soil, you can effectively manage this problem.
Photos of Necrotic Ring Spot Lawns
(Click on Images to Enlarge)
How to Cure Necrotic Ring Spot Fungus In a Lawn
Rebuild the Soil is the Key to Curing Necrotic Ring Spot
Step 1: Fix the Lawn Watering Problem
The most important step is to address the issue of overwatering the lawn. Necrotic Ring Spot is typically found in areas that are excessively moist or wet, particularly where drainage is poor. To help remedy this, follow the 1-2-3-2-1 lawn watering technique. This method allows adequate time between lawn watering cycles, giving adequate time for the soil to dry out completely. Additionally, it’s crucial to water early in the morning rather than late at night. If overwatering isn’t resolved, the lawn fungus problem will persist. Organo-Lawn will not guarantee curative results for your lawn in the Boulder or Fort Collins area unless an Organo-Lawn employee performs a sprinkler startup or audit.
Furthermore, it is essential to rebuild the beneficial microbial populations in the soil. The fungus will continue to be an issue until microbial activity is restored. Please note that rebuilding the soil takes time; a severe case of necrotic ring spot may take 1-2 years to fully recover.
Step 2: Core Aeration
Perform 2-3 lawn aerations, one in early spring, one in late spring, and one in the fall to alleviate soil compaction and introduce air into the soil so the microbes can breathe. Air is vital to establishing a living soil and the more a lawn is aerated the faster the lawn will recover.
Double aeration is a good idea for lawns with severe necrotic ring spot damage or for people that want to speed up the recovery process.
Step 3: Remove the Dead Grass
Manually remove the dead grass in the necrotic ring spot circles. You can do this using a heavy metal rake.
Step 4: Apply Humate Soil Conditioner
Stimulate beneficial microbial activity by applying Humate soil conditioner 2-3 times per year. Humate will stimulate beneficial microbial activity and help break up compacted soils.
If you don’t have access to a Humate soil conditioner product try to use a 100% organic soil conditioner or compost as an alternative.
Step 5: Only Apply High Quality Organic Fertilizers
- Never fertilize the lawn with fast release or inorganic nitrogen sources. Fast release nitrogen is typically white in color and high in salt. These synthetic nitrogen sources kill beneficial microorganisms and will hinder the recover process.
- Change all fertilization to organic fertilizers. Chemical fertilizers are high in salts and kill microbes. A very good organic fertilizer for curing necrotic ring spot is Synergy with Corn Gluten Meal.
Step 6: Proper Lawn Mowing
Never mow the grass when it is wet, and always wait 24 hours after a mowing to water the grass. After a mowing the grass blades have been damaged. It takes 24 hours for a grass to repair the abrasion. If water is added to the lawn before the lesion has time to heal, the fungus can use the water as a transportation mechanism and infect new and otherwise healthy blades of grass. Make sure to mow the grass at 3 inches or taller.
Until the necrotic ring spot fungus is eliminated, bag the grass in the infected area, increase the mowing height to 3” or 3.5”, and increase the mowing frequency so no more than 1/3 of the blade of grass is removed per mowing.
Step 7: Be Patient
Patience is a key factor for homeowners tackling lawn issues, but it can often be the toughest challenge when dealing with Necrotic Ring Spot. Depending on the severity of the infestation, it may take up to 2 years to fully recover the lawn. The reason for this is because it takes a long time to rebuild the beneficial microbial population in the soil.
If the lawn hasn’t made much progress after following steps 1-6 and a full year has passed since you started treatment, the reason may be that the soil is still lifeless or lacking in beneficial microbial activity. This means that one of the key elements in soil recovery is still not correct. Just like all living things, microbes need 4 basic elements to thrive: air, heat, water (keeping it moist but not waterlogged), and food (organic matter) to thrive.
If the lawn is not improving, it is essential to ensure one or more of these vital elements—air, water, heat, and food—are being properly addressed. Overwatering is particularly detrimental and is usually the element that is still out of balance.
It’s critical to note that we strongly advise against using fungicides. These chemicals destroy beneficial microbes, hindering your efforts to revitalize the soil. Our findings consistently show that lawns experience much faster recovery when fungicides are not applied, as they can eliminate helpful microbes for up to three months after application. For the best results, steer clear of fungicides—it’s a necessary step toward restoring your lawn’s health.
If You Aren’t the Patient Type!
We offer compost top dressing services at an additional charge for customers that want to dramatically speed up the recovery process. We have found that one application of a high-quality compost can enhance the recovery time by up to 2 times faster.
The reason that compost top dressing is so effective is because a high-quality compost is already teaming with millions of microbes. Therefore, instead of rebuilding the microbial populations naturally, the compost top dressing will introduce the microbes organically.
Typical Schedule for Treating Necrotic Ring Spot Fungus in Colorado
Early March: Single or Double Aeration and Synergy Application
Mid April: Sprinkler Audit and Humate Soil Conditioner Application
Mid May: Single or Double Aeration and One Earth Weed Control Application
Late June: Synergy Application and Humate Soil Conditioner Application
August: Synergy Application
Early September: Single or Double Aeration and Humate Application
October: Single or Double Aeration and Synergy Application
Optional (Any Time of Year): Compost Top Dressing (Compost Top Dressing Speeds Up Soil Recovery by 2X)
Does Your Lawn Have Necrotic Ring Spot?
Treating necrotic ring spot fungus may seem straightforward; however, correcting the watering practices can be complicated.
Organo-Lawn is here to help!
Boulder (303) 499-2000
Fort Collins (970) 225-9425
Photos of Necrotic Ring Spot Fungus – (Click on Images to Enlarge)
Necrotic Ring Spot Treatment FAQs
How to Fix a Necrotic Ring Spot Lawn?
To effectively address Necrotic Ring Spot, it’s essential to focus on eliminating the underlying cause rather than simply treating the symptoms. Infestations of Necrotic Ring Spot fungus in a lawn typically indicate that the lawn has been overwatered for an extended period. Severe overwatering creates an anaerobic environment in the soil, displacing air and allowing only certain types of soil microbes to thrive.
To remedy the fungal problem, the most crucial step is to water deeply but infrequently, following the 1-2-3-2-1 lawn watering technique. Creating a living soil rich in microbial activity is key to curing Necrotic Ring Spot. A diverse and competitive microbial population in the soil contributes to a healthier lawn.
Effective lawn care practices to help heal Necrotic Ring Spot without the use of chemicals include using humate soil conditioners, performing lawn aeration, and mowing properly. It is important to avoid applying lawn fungicides to areas affected by Necrotic Ring Spot, as these products can eliminate both harmful and beneficial microbes in the soil, which is counterproductive to curing the fungal issue.