If your grass has begun to develop yellow streaks or patches in the 2 weeks following fertilization, it is in the early stages of fertilizer burn. In order to save your grass, water the affected areas for 1 hour daily for up to two weeks. This will feed the grass and wash out the excess fertilizer.
If areas of your lawn have been killed by too much fertilizer, the only solution is to replace the dead grass. First, remove the dead grass along with the top 3 inches of soil. This topsoil is poisoned with excess fertilizer and will kill new grass and any seed planted there. Add new topsoil to the area, then overseed or lay sod to replace the grass that was killed.
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How Can You Tell if Your Lawn has Fertilizer Burns?
Fertilizer burns are characterized by patches of grass in a recently fertilized lawn that appears yellow or brown. These burns can appear 1-2 days after fertilizer application but may take as long as 2 weeks to appear. After fertilization, water your lawn regularly and monitor grass conditions.
- Fertilizer burns may appear in as little as 1 day or up to 2 weeks after you spread fertilizer.
- Burns appear as yellow or brown patches of grass in your lawn.
- Grass burned by fertilizer may take on a “streaky” appearance and will be dry.
Grass that seems dry, brittle, or begins to show streaks of yellow or brown after fertilization is probably suffering from fertilizer burns. If this happens, begin daily watering of the affected area immediately.
What Causes Fertilizer Burns in Grass?
Fertilizer burns are caused by excess nitrogen in the soil. When too much nitrogen is present from fertilizer, it soaks up moisture, even pulling it out of the roots and stems of grass. This contributes to the yellowing, browning, and death of grass.
- Excess nitrogen from fertilizer absorbs water from the soil and grass roots.
- Nitrogen overload creates a “false drought,” starving grass of water.
Essentially, too much nitrogen creates drought conditions because it steals water that would otherwise feed your grass. Like any drought, the best solution is to provide water.
How to Repair Fertilizer Burns in Your Lawn
If you act quickly, you can often save grass that is afflicted with fertilizer burns. However, grass that has been heavily damaged by too much fertilizer may be killed. In this case, you will have to remove the dead grass and carefully reseed it.
What to Do if Grass is Yellowed
If your grass has begun to yellow or dry out after you’ve applied fertilizers, the best course of action is to apply water early and often. The water will help flush out the fertilizer and feed the grass simultaneously.
- Water affected area(s) daily for 1 hour in the morning.
- Continue watering for up to 2 weeks, or until the grass begins to green again.
1 hour of watering with a sprinkler each day will help fertilizer burned grass recover. Make sure to water in the morning. Watering in the evening leads to standing water remaining overnight, which can invite fungus and grass diseases, hindering lawn recovery.
What to Do if Grass is Brown
If your grass has completely browned and uproots easily when pulled, then it has been killed by fertilizer burns. While yellow grass can be recovered by watering, brown grass can’t be helped. It’s time to repair this area of your yard. To do so:
- Use a rake and shovel to uproot dead grass and 2–3 inches of topsoil.
- Fill in the area with new, fertilizer-free topsoil.
- Overseed the new topsoil with a grass mix that matches your lawn.
- Water the overseeded area 15 minutes per day for 1-2 weeks, to ensure grass seed sprouts.
- Instead of spreading grass seed, consider laying sod next to existing grass to patch your yard.
When serious fertilizer burns kill grass there’s no way to save the grass. That’s why it’s important to monitor your lawn closely after applying any high-nitrogen fertilizer. Look for signs of grass stress and yellowing to begin a watering regimen quickly and save your lawn.
How to Prevent Fertilizer Burns in Grass
It’s possible to prevent fertilizer from damaging your yard. Below are low maintenance, lawn-safe tactics to prevent the symptoms of fertilizer burns from appearing in your lawn.
Use Non-Burning Fertilizer
A slow-release fertilizer, such as Milorganite, has a much less chance of burning your grass than standard chemical fertilizers. While chemical fertilizers release large amounts of nitrogen into your soil immediately, slow-release fertilizers feed nutrients into the soil over time, preventing a harmful nitrogen overload.
- Choose fertilizers labeled as “slow-release”
- Avoid “fast-release” fertilizers.
- Milorganite is a sustainable fertilizer that won’t burn your lawn.
Lawns treated with Milorganite will not burn. This is because Milorganite feeds soil microbes that only release nitrogen to your grass as needed. If you’ve struggled with fertilizer burns in the past, Milorganite is the best solution, either alone or with other fertilizers.
Use Fertilizer as Intended
When applying fertilizer, always review and follow product guidelines for application rates per square foot. If bag rates for fertilizer specify that it is meant to be applied to 500 square feet and the fertilizer is applied to a smaller area, this can result in fertilizer burns.
Establish a Fertilizer Application Schedule
In order to reduce the risk of fertilizer burns, follow a hybrid fertilizer program that uses non-burning fertilizers in early spring and summer, and stronger fertilizers in late spring and fall. This will not only boost lawn performance but also prevent grass death. Milorganite and Scotts Turf Builder are good choices for a hybrid fertilizer approach.
- Follow a hybrid fertilization program that includes non-burning fertilizers.
- Allow fertilizer to work for 4–6 weeks before performing a follow-up application.
- Avoid using high-nitrogen fertilizers during dry conditions and peak summer heat.
Fertilizer requires time to feed grass. Although some fertilizers can show results in just a few days, they often continue working for 4-6 weeks. Allow the fertilizer to run its course before fertilizing again. Additionally, because high-nitrogen fertilizer steals water from grass, refrain from using it during extremely hot and dry conditions. The risk of fertilizer burns increases during peak temperatures and drought conditions.
Provide Adequate Water
Create a watering schedule for your lawn. Although optimal watering levels depend on the type of grass you have in your yard, some general guidelines apply to almost all turf grasses:
- Water deeply and infrequently. Watering twice per week for a longer time is better than watering daily for short periods.
- Water in the early morning (5–7 AM), to prevent water evaporation and grass disease.
- Most grass thrives with 2–2.5 inches (5–6.5 cm) of water per week. This can be provided by two 30–40 minute watering sessions per week.
By watering deeply, you encourage grass to develop deep roots. This increases your lawn’s ability to survive drought and the application of high-nitrogen fertilizer. Watering the right way will reduce the chance of fertilizer burns.
How to Fix Fertilizer Burns in Grass
Grass that has been dried out due to excess fertilizer can often be revived by daily watering until the grass begins to green again. In severe cases, fertilizer overload can kill patches of grass. In this case, the dead grass must be removed, along with overfertilized topsoil. Then, new topsoil should be added and grass seed spread in the area.
By using fertilizers that won’t burn your lawn and employing good fertilization and watering schedules, you can prevent fertilizer burn from occurring. Carefully choose the right type of fertilizer for your lawn and you’ll enjoy the benefits of beautiful, undamaged grass.