How Do You Know You Over-Fertilized Your Lawn? (2024)

Depending on your grass type and where you live, it may be time to fertilize your lawn. So, you go to the local home and garden store, get your fertilizer, spread it out, and then – disaster strikes! Instead of looking lush, your lawn is now brown and sporting patches. The likely culprit? Over-fertilization.

But how do you know you over-fertilized your lawn, and what can you do to fix it? Learn about what to look for, how to prevent it, and how to help your lawn recover from over-fertilization.

How do you know you over-fertilized your lawn?

Whether you believe it or not, you can over-fertilize your lawn if you’re not careful. Fertilization doesn’t just involve dumping lawn fertilizer on your grass and calling it a day; you must follow specific guidelines and application techniques if you want that dreamy lawn.

And while not all homeowners can easily identify when they’ve put too much fertilizer on their lawn, certain signs indicate this problem. The most recognizable sign that something just isn’t right is the crusting of fertilizer on top of the soil. But that’s not all; look for these additional signs of over-fertilization in your yard:

Leaf tip browning

Also known as “fertilizer burn,” brown grass is a clear sign of excess fertilizer, especially nitrogen. It occurs when the concentration of nutrients is too high, overwhelming and possibly killing the grass. You’ll usually notice brown patches throughout your lawn.

Wilting or yellowing

If your grass is wilting, turning yellow, or showing general signs of stress, it could be a result of over-fertilization. The lawn could be struggling to absorb an exaggerated amount of nutrients it doesn’t need. Without proper action, the result will be dead grass.

Excessive grass growth

Paradoxically, over-fertilized lawns may exhibit rapid and inordinate growth. But don’t get too excited. This growth will be weak, and your lawn will be susceptible to diseases or pests, which is probably not what you want. Alternatively, you may notice extremely slow grass growth or none at all.

Fertilizer runoff and a strong smell

Too much fertilizer on your lawn can result in fertilizer runoff, which you can detect by the following:

• If your grass is turning yellow or brown, growing thin, growing where it shouldn’t, or looking patchy, and you’ve noticed pests and weeds popping up, it’s highly likely that fertilizer runoff exists on your property.
• If you have a body of water nearby, check it for unusual coloration, such as red, green, or brown, which can indicate nutrient runoff, such as excess nitrogen or phosphorus. The water may also contain algal blooms, a toxic growth that can harm fish and other aquatic organisms.
• An unpleasant, musty, earthy odor coming from a body of water (even a puddle) nearby. Excessive organic matter decomposition leads to foul smells, which may linger, especially if the organic matter itself has a strong smell to begin with. Other influencing factors include weather conditions (high temperatures and humidity) and water movement, which can disperse the smell over larger areas. In contrast, stagnant water can maintain the smell just as well – and likely keep it concentrated.
• You may also notice unplanned plant growth near bodies of water, another sign of possible fertilizer runoff. Since the runoff is chockfull of macronutrients, the soil it touches can become fertile and promote the germination of any existing seeds nearby. As a result, areas affected by fertilizer runoff will see an increase in vegetation.

Fertilizer buildup

If you over-fertilized your lawn, you’ll likely detect a white, crusty consistency to your grass, a sign of fertilizer buildup.

When fertilizers containing soluble salts are applied and watered into the soil, the water evaporates, leaving the salts sitting on the soil surface. Therefore, too much fertilizer will manifest as a white substance on your lawn.

Patchy grass or no grass growth

Too much fertilizer will almost always lead to an imbalance in nutrient distribution and patchy areas in your lawn (think areas with no grass at all – ring a bell?). A healthy lawn will always look even, green, thick, and lush. Alternatively, you may notice extremely slow grass growth or none at all.

Weeds

Certain weeds thrive in nutrient-rich environments. They go by the name nitrophilous or nitrophytic weeds due to their ability to adapt to soils with elevated levels of nitrogen and other nutrients. Some common types include:

• Pigweed (Amaranthus spp.)
• Lambsquarters (Chenopodium album)
• Canada Thistle (Cirsium arvense)
• Burdock (Arctium spp.)
• Smartweed (Polygonum spp.)
• Chicory (Chicorium sp.)
• Common Purslane (Portulaca oleracea)
• Dandelion (Taraxacum officinale)
• Chickweed (Stellaria media)

Weeds also sprout in areas with little to no grass, their presence indicating soil disturbance or nutrient imbalances. In such cases, grass will have a hard time growing thick and strong, leaving room for weeds to establish themselves. They take advantage of open spaces in the soil to germinate and overtake the area. Not to mention that sparse grass allows sunlight to better reach the soil surface, helping weeds germinate.

Pest infestations

Stressed, weak grass (remember that excessive growth?) coupled with environments with ample resources attract various pests looking to feed and reproduce. Look for these common pests associated with nutrient-rich environments:

• Spider mites
• Aphids
• Whiteflies
• Fungus gnats
• Root-knot nematodes
• Caterpillars
• Thrips

An important aspect of responsible lawn care is the implementation of integrated pest management practices. These include regular lawn and garden monitoring, maintaining proper soil nutrition, and using appropriate control methods when needed.

How does over-fertilization happen?

Accidentally over-fertilizing your lawn is easier and more common than you think. Here are some ways this can happen:

• Misjudging application rates: It’s never a good idea to add extra fertilizer in the hopes of seeing better results. Since slow-release fertilizers and quick-release fertilizers have varying application rates, following guidelines to a T can make or break your lawn. The same can be said of liquid and granular fertilizer. Never assume or deviate from the instructions, but stick to the amount indicated on your fertilizer bag.
• Uneven application: Spreading your fertilizer haphazardly can result in over-fertilization, with some areas receiving too much fertilizer and others too little. Lawn size also matters. If you’re applying granular fertilizer, use a rotary spreader (ideal for larger lawns) or a drop spreader (ideal for smaller turfs). To apply liquid fertilizer, use a lawn sprayer to coat the turfgrass evenly. As for organic fertilizer such as compost, apply it with your hands, as it can sometimes get stuck in the spreader.
• Inaccurate timing: Fertilizing during the wrong season or weather conditions can contribute to over-fertilization. For example, applying fertilizer during drought may increase the risk of burning your grass. Likewise, the wind can blow your fertilizer in every direction, leaving some areas empty while overloading others.
• Using the wrong fertilizer: Neglecting to conduct a soil test before fertilizing, not knowing your grass type, or disregarding soil test results can lead to incorrect fertilizer choices and application rates, harming your grass. You may end up using a highly concentrated fertilizer or applying a quick-release variety incorrectly, leading to an overdose of nutrients in the soil.
• Fertilizing too often: If you’ve recently fertilized your lawn and now want to apply more product without allowing sufficient time for the previous application to take effect, you may inadvertently over-fertilize.

What to do if you over-fertilized your lawn

If you suspect you over-fertilized your lawn, these steps can help reverse the damage:

1. Remove excess fertilizer: The first thing you should do is remove any fertilizer buildup from the affected areas. Use a rake to collect any fertilizer clumps and a broom to sweep them up.
2. Water your grass: On the first day, water your lawn until it can’t take any more water. This flushes out all the salts, giving the roots a chance to recover. It also helps dilute the excess fertilizer and move it deeper into the soil, reducing the risk of fertilizer burn. Continue saturating your lawn with at least 1 inch of water daily for a week.
3. Take a break from mowing: For your grass to absorb more nutrients, it needs to grow longer, which means mowing is a no-no in the case of over-fertilization. Take a break from your regular mowing schedule and let the grass breathe for about a week.
4. Avoid further fertilization: This goes without saying, but it’s best to not fertilize your yard for a while. This could mean skipping your next scheduled fertilization (check out our guide on how often you should fertilize your lawn).
5. Aerate the soil: Aeration can facilitate better water and nutrient absorption, helping to alleviate any compaction caused by over-fertilization. Gypsum application can also help alleviate this problem, as it contributes to better soil quality.
6. Monitor your lawn: Keep a close eye on your lawn for any signs of further stress or damage. Adjust your watering routine to include more moisture if you notice extreme yellowing or browning. Remember that yellow grass stands a good chance of bouncing back. If your grass is brown, you may have to concede that it’s dead.
7. Reseed if necessary: In some cases, no matter how much corrective action you take, your grass may still die, meaning overseeding will be necessary to fill in bare spots. Before you do this, remove all the excess fertilizer and add some topsoil. Follow up with a sprinkling of new grass seed and daily watering until proper establishment. This means around 3 to 4 inches of water per week in the beginning stages.
8. Consult an expert: If your grass just isn’t recovering or has stunted growth, consider the advice of a lawn care professional. They can assess the situation and provide guidance on potential corrective measures to benefit your damaged grass.

FAQ about over-fertilizing your lawn

Can an over-fertilized lawn fully recover?

An over-fertilized lawn can recover with prompt corrective actions, regular monitoring, and adjusting lawn care practices according to grass type and its needs. Remember that each lawn is unique, so what worked for your neighbor may not work for you. Always discuss any concerns with a professional if unsure about proper action.

What role does nitrogen play in fertilizer?

Nitrogen is one of the three necessary macronutrients present in fertilizer and is responsible for:

• Healthy growth
• Protein synthesis
• Leaf development
• Maintaining established lawns

Generally, you’ll need 1 pound of nitrogen per 1,000 square feet of lawn, but pay attention to the amount listed on the packaging. The higher the amount of nitrogen, the less fertilizer you’ll need to apply.

How does too much fertilizer impact the soil?

When you over-fertilize your lawn, you negatively impact both your lawn and the soil. More specifically, you contribute to soil acidification and a reduction in organic matter and soil organisms. In essence, the salts in the fertilizer can affect soil quality, thus stunting grass growth.

Is slow-release (controlled-release) fertilizer better than quick-release?

Given a choice between the two, opt for slow-release fertilizer. This variety guarantees long-term lawn health without any toxicity. It helps with water movement and soil structure, introduces beneficial soil microbes, and is safer for children and pets. That said, quick-release fertilizer can be a viable option if you’re looking for fast results, a lower price point, and a higher concentration of nutrients.

Ultimately, the right fertilizer will depend on your lawn’s needs and how much time and money you’re willing to spend on it.

Why is fertilization necessary?

Fertilization helps your lawn fight a multitude of external enemies. Here are some benefits of fertilization:

• Provides the necessary macronutrients your grass needs to grow thick and healthy. These are nitrogen, phosphorus, and potassium – usually written as N-P-K.
• Promotes healthy grass growth. With the necessary nutrients backing it up, your lawn will look luscious and stay green longer. Say goodbye to dry patches, discoloration, and weak grass blades.
• Prevents weeds. Fertilizer carries weed-control treatments, giving grass the tools to grow thick and strong without falling victim to weed attacks.
• Creates a disease barrier. Regular fertilization makes lawns less disease-prone and more resistant to attacks. In case of any stress, your lawn will bounce back much faster.
• Keeps pests at bay. A fertilized, thick, sturdy lawn won’t be as easy to attack. Plus, certain fertilizers contain insecticides known to kill pests and prevent infestation.

What’s the best lawn fertilizer on the market?

With so many options at your disposal, it’s never easy to find the right fertilizer for your lawn. But we’re not about to leave you hanging or scratching your head. Check out our list of our best fertilizers of 2024. Chances are, our helpful guide will be just what you need.

Give a pro the chance to fertilize your lawn

If you’re worried about over-fertilizing your lawn but still dream of that lush paradise you only see in the movies, call a lawn care expert today. They can fertilize your lawn according to its needs and elevate your outdoor space with professional, hassle-free services.

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