Nutrients are essential for all plants to grow and develop properly. In open, natural environments, these nutrients are found naturally in soils. Sadly, these nutrients get depleted from the soils of thriving, active farms and gardens. Fertilizers are necessary for such soils.
However, fertilizer application might be challenging because you must use the correct amount. A little too much fertilizer might cause overfertilization and fertilizer burn in plants. In agricultural farming, fertilizer burns can cause plants to turn yellow or brown and a significant, occasionally complete, loss of output.
This is why you should know what fertilizer burn is, the causes, and how to fix it.
What is Fertilizer Burn
Fertilizer burn is a major inconvenience. It occurs when you apply fertilizer in doses greater than the plant can handle.
Fertilizers mainly consist of salts. If these salts are in excess, they accumulate and remain in the soil, causing an osmotic imbalance, where excess salts surround the plant roots, drawing out water from the plant cells and preventing plants from absorbing the nutrients.
This results in dehydration, and once your grass is affected at the root level, the plant loses its health and exhibits symptoms like wilting, yellowing leaves, and brown, scorched edges on leaves. In severe cases, fertilizer burn can cause the plant to die if the damage is not corrected by leaching the soil with water to dilute the salts or reducing fertilizer use.
Most fertilizers are either rapid or slow-release. The effects of overfertilizing with rapid-release formulas will appear fairly quickly. Meanwhile, symptoms caused by slow-release formulas can take up to two weeks to appear.
A fertilizer burn may appear different depending on the setting.
Lawn
Brittle Yellow/Brown Grass
In a grass lawn, fertilizer burn appears in the form of patches of dead grass that have turned yellowish or brownish. These affected areas feel noticeably different to the touch. The grass may be crispy, brittle, or crusty, indicating severe dehydration and cell damage.
Checkerboard Pattern
Sometimes, applying fertilizer with a lawn spreader causes overlapping coverage and uneven application. When this occurs, the burned grass may appear in checkerboard patterns, with brown or yellow patches in the middle of each square. Surrounding areas, with even fertilizer application, often remain healthy and green, making the checkerboard pattern more noticeable.
Bare/Sparse Areas
Fertilizer burn doesn't only show up as dead, yellow, or brown patches of grass checkerboard-like patterns; it is also noticeable when new grass fails to grow in areas where it should. Excess fertilizer interferes with germination and growth, resulting in bare or sparse areas.
Crops that receive too much fertilizer may experience defoliation, which is the early loss of leaves. The leaves, among other plant components, are stressed from excess fertilizer; they dry out, turn yellow or brown, and eventually fall off.
Root Discoloration
Another way to check is to observe the color of the roots. Healthy roots are white and firm. If you pull your plants out of the ground and the roots are blackened or brown and limp, you can be sure that you are either giving your plant too much water or fertilizers.
When you dig out the plant, the soil should not be overly wet to rule out excess water. If you suspect fertilizer burn, look for other signs, such as yellowing or scorched leaf edges and stunted growth.
Houseplants
White Crust: One of the early signs of using overly strong fertilizer or applying too frequently is a white crust on the soil surface, inside or outside of the pot, or foliage and stems. The crust indicates salt accumulation. If changes don't occur, fertilizer burn may happen soon.
Brown Leaf Tips and Margins: Brown leaf tips and edges indicate incorrect watering and/or fertilizing. When you see this after a fertilizer application, chances are roots are taking up excess salt, causing foliage to become dry and brittle.
Stunting: Plant growth slows or stops entirely. New leaves fail to develop, turn yellow or brown, and drop. Plants form flower buds that drop before opening. Salt buildup diverts moisture from the roots, slowing photosynthesis and inhibiting new growth.
Wilting: Leaves become limp and droopy, eventually turning black and falling off. Stems lose rigidity. The plant may fall over or collapse. Roots are desiccated or blackened, damaged by excess salt, and unable to provide the nutrition the plant needs to survive.
Common Mistakes that Cause Fertilizer Burn
Most cases of fertilizer burn can be prevented simply by reading the label on your fertilizer products and following all instructions. Labels on reputable products typically cover desired rates, recommended application methods, and conditions that would prevent lawn and plant damage. Some of the most common mistakes that lead to fertilizer burn include:
Applying more than the label-recommended rate may cause more harm than benefit when it comes to fertilization or any other lawn and garden product. The recommended application rates, as given on the label, maximize the benefits available to your plants. Thus, surpassing them causes damage to plants from burns.
Miscalculating the size of the area you are fertilizing.
According to the pros, you should get your figures right when fertilizing based on an area's size. For lawns, measure the entire perimeter, but do remember: any non-lawn sections, such as your house, outbuildings, and driveways, should be deducted, or you will most probably end up overapplying.
Guessing at fertilizer quantities.
Fertilizers should be applied with the correct dose so your plant can receive the nutrients without adverse effects. Guessing the amount to use leads to over-fertilizing, which burns the plant because of the excess nutrients, particularly salts. This issue is more critical when applying fertilizer to individual plants concentrated in one area. There is no margin for error.
Therefore, it is always best to measure fertilizers with dedicated measuring cups. This results in an accurate and consistent usage. Measuring fertilizer before each application may take some time, but it ensures no mistakes and protects your plants whilst maximizing the benefits of your fertilizer.
Not knowing how to use a spreader properly.
Leaving the spreader hopper open while filling, stopping, or turning while using the spreader allows fertilizer to spill out in concentrated amounts. These excess piles of fertilizer can overwhelm the soil and plant roots, leading to fertilizer burn—an effect caused by too much salt in the fertilizer, drawing moisture away from plants. This damages or even kills them.
To avoid this, always close the hopper during filling, stopping, or turning. You will prevent unintentional over-application, keep fertilizing as uniform as possible, and allow your plants to thrive while protecting them from unnecessary damage.
Your plan to help your dry or stressed lawns and gardens recover may backfire if you use fertilizers. When plants are stressed from drought, poor soil, disease, or extreme weather, they have weak roots and overall system. Under such circumstances, fertilizer would add nutrients to the already stressed soil. The burden of the nutrients in the soil would further stress the plants as it alters the soil balance or accumulates salts.
You should address the underlying issue before fertilizing. Understand what is causing the stress. It could be from incorrect watering techniques, problems in the soil, or diseases. Once plants recover, they will better utilize the nutrients, leading to healthier growth.
Using inappropriate fertilizer products.
Choosing the right plant fertilizer is certainly not about randomly picking anything you can find. There are varieties in the market, and each with specific purposes. Most home gardeners use general ones such as a balanced 10-10-10 blend (equal parts of nitrogen, phosphorus, and potassium) which works well for any plants.
For example, high-nitrogen lawn fertilizers encourage fast grass growth. However, they are overwhelming for delicate plants like azaleas, causing root damage or nutrient burn. Similarly, weed & feed products or crabgrass preventers often contain herbicides that can damage young seeds or seedlings. To avoid problems, always match the fertilizer to the plants and their growth stage.
How to Fix Fertilizer Burn
If you realize your plant may be suffering from fertilizer burn early, you can make adjustments to save it.
Flush the Pot
The first thing to do is flush the excess salt away. When you rinse the soil with cool and clean water several times, the excess salt drains from the pot drainage holes. To do that, hold the pot under a running faucet or fill a container and dump it, wait a few minutes, and repeat.
As you do this, make sure the soil is draining. The first rinse dissolves accumulated salts, and the second cleans the potting medium. Do not leave standing water in the pot saucer. Dump it. If not, the plant will reabsorb salts left in the water. Repeat once a day for about a week.
Manual Removal
If you see white crusts on the soil surface, you can remove them manually. Carefully scrape off the top layer of soil where the crust has formed using a small tool, such as a spoon or garden trowel.
Once the crust is scraped off, replace the lost soil with a fresh, nutrient-free potting mix to maintain the plant's stability and prevent any imbalance in the container. This method prevents the excess salts from leaching into the lower soil when you water the plant, where they could continue to harm the roots.
Use Distilled Water
In certain regions, tap water naturally contains dissolved chemical salts. Over time, as you water your plants, these salts can build up in the soil or even on the surface, creating white, crusty deposits. The quality of water, not the fertilizer, might be the problem if your plants struggle to recover or keep developing these deposits.
Consider using distilled, rain, or purified water to reduce salt build-up. Another option is to boil tap water to remove some salts and chemicals. Let the water cool and sit for 24 hours after boiling to allow sediments to settle and chlorine to dissipate before watering your plants.
Repot
If flushing the pot does not work or fertilizer burn damage is extensive, repotting the plant may help. Repotting does not only mean changing the current pot current. It also means to change the soil or potting mix. Fresh soil means new nutrients, one without excess salts and chemicals.
Start by watering the plant to dampen the roots for easy removal. Tap the bottom of the pot until the plant slides out, and gently untangle the roots. Then, remove about one-third or more of the potting mix surrounding the plant. While at it, inspect the roots and prune out any dried-up or discolored. Prune partially damaged roots back to healthy tissue. Gently rinse with cool, clean water and repot using fresh material.
Replant the plant in a fresh pot with a new potting mix. Water your plant as per the regular schedule, but withhold fertilizer until the plant recovers. When new buds and leaves appear, resume your usual feeding schedule with fertilizer diluted to half-strength.
Reseed
If you are dealing with grass damage on your lawn, you may have to start from scratch. After flushing out the soil, the lawn should recover within a few weeks. It should have new grass growth, or the current grass should start looking healthier. If neither is happening, reseed affected areas with new grass seeds.
Dig up the dead grass from the roots, spread new grass seeds, and wait for fresh grass to appear. Apply fertilizer about 4 to 5 weeks after new grass growth, following the instructions to the tee to avoid a repeat fertilizer burn problem.
How to Prevent Fertilizer Burn
For healthy grass, it is better to know how to avoid fertilizer burn then learn how to treat it later. Use these tips to ensure fertilizer doesn't harm your lawn.
Hold off fertilizing until the drought is over. Fertilizing during a drought is harmful because there isn't enough rain to dilute and distribute the fertilizer into the soil. The fertilizer remains concentrated in the soil, increasing the risk of fertilizer burns.
Thoroughly water your yard after applying granular fertilizer to your lawn. Doing so would effectively wash away the fertilizer from the blades of grass or leaf surface and distribute most of it, if not all, into the soil for even penetration.
Use compost or organic fertilizer as they are gentler, reducing risk of fertilizer burn. They also keep the plants and grass healthy.
Employ slow-release fertilizers. These fertilizers are suitable for plants or lawns with frequent fertilization needs. The nutrients in the fertilizers are released into the soil gradually, minimizing the risk of over-fertilizing.
Do not fertilize wet grass. Applying fertilizer when the soil or plants are damp increases the risk of fertilizer burns. Thus, only apply fertilizers on dry grass and soil.
Before you apply fertilizer, research the required fertilizer amount for your lawn size or the plants and grass you have. Follow the recommendations to use the right amount and avoid overfertilizing your yard.
