What Is Fertilizer Burn? Signs You're Overfeeding Your Plants & What to Do Before You Fertilize Your Plants to Death

We gardeners love our plants. We spend huge parts of our summers watering, plucking weeds, pruning, and picking bugs off of every plant in the garden. But when it comes to fertilizing, we can accidentally give our plants too much love and end up causing fertilizer burn.

Overfertilization in the garden, which is often the result of good intentions, can harm plants and lead to fertilizer burn. Using too much fertilizer on plants is a serious problem that can actually cause more damage than too little fertilizer.

So I’m here to answer the question, “What is fertilizer burn?” and tell you what you can do about it. I’ll describe the symptoms of fertilizer burn in plants as well as how to prevent and treat it. Plus, I’ll provide some simple tips to follow about how to use fertilizer that will help your garden thrive.

What Is Fertilizer Burn?

Simply put, fertilizer burn is a condition that results in the burning or scorching of plant foliage. Fertilizer burn is the result of overfertilizing plants or applying fertilizer to wet foliage.

Fertilizer contains salts, which draw moisture out of plants. When you apply excess fertilizer to plants, the result is yellow or brown discoloration in the foliage and root damage.

What Does Fertilizer Burn Look Like?

Fertilizer burn symptoms may appear within a day or two, but it may take a couple of weeks to show up if you use a slow-release fertilizer. Symptoms include yellowing, browning, and withering. In lawns, you may see white, yellow, or brown streaks that follow the pattern in which you applied the fertilizer.

Lightly damaged plants may simply wilt or look generally unwell, but plants that are seriously burned may appear to have actual burns: their leaves will turn brown and collapse from the edges inward. This is due to the accumulation of fertilizer salts in the plant tissues and a lack of water to flush them out due to root damage.

How to Prevent Fertilizer Burn

The good news is that fertilizer burn is easily preventable. Here are some tips to help you avoid fertilizer burn on plants:

• Fertilize each plant according to its needs. You won't get better results when you use more than the recommended fertilizer application rate and you also run the risk of damaging or killing your plants.
• Using a slow-release fertilizer, like this organic all-purpose plant food from Burpee, reduces the chances of fertilizer burn of plants by releasing the salts into the soil gradually rather than all at once.
• Fertilizing your plants with compost eliminates the risk of fertilizer burn. Most plants thrive when fed with a 1 to 2 inch (2.5 to 5 cm) layer of compost once or twice a year. Make your own compost at home with an easy-to-use compost tumbler, like this one from Amazon.
• Plants are more susceptible to fertilizer burn during a drought because the fertilizer will become more concentrated in the soil without rainwater leaching the salts out of the soil. Don't fertilize during hot, dry spells. Instead, wait until moisture returns to feed plants.

• Never fertilize wet lawns or allow fertilizer to come in contact with wet leaves as this can cause fertilizer burn. The best time to fertilize is after plants have received water, but are their foliage is dry.
• Water deeply and thoroughly after applying granular fertilizer to rinse the fertilizer off the plants and allow the salts to distribute themselves evenly in the soil, so they don’t damage delicate plant crowns and tender roots near the surface.
• Test your soil before applying fertilizer. A simple soil test kit, like this one from Amazon, tells you exactly what your lawn or garden needs so you don’t have to guess about the nutrients or quantity to provide.
• Using a broadcast spreader, like this one from Scotts, also helps to more evenly distribute fertilizer over large areas like your lawn.

How to Fix Fertilizer Burn

Overfertilized plants can sometimes be saved, depending on the amount of fertilizer you applied and how quickly you act. Managing fertilizer burn in the garden depends on your speed at recognizing the signs in your plants.

If you suspect you may have overfertilized your plants, treat the area as soon as possible. Treat spillage by scooping up as much of the fertilizer as possible. Then the only thing you can do for overfertilized soil is to flush it with as much water as it will hold over the next few days in order to leach the soil of excess fertilizer.

When you realize you've overfertilized, either because of plant symptoms or due to a white, salty crust that forms on the soil's surface, immediately begin flooding the garden. A long, deep watering can move many types of fertilizer from the soil near the surface into deeper layers, where roots aren't currently penetrating.

Much like leaching salts from a potted plant that's had too much fertilizer, you're going to need to flood your garden with a volume of water equivalent to the cubic area of the fertilized area. Flushing the garden will take time and a careful eye to ensure that you're not creating standing puddles of waterrlogged soil that will drown your already burned plants.

Don't allow the water to run off either. Toxic runoff can contaminate nearby areas and may get into waterways where it causes substantial damage to the environment. Water slowly to allow the water to sink in rather than run off.

Can You Overfertilize Grass?

It’s possible to overfertilize grass just like any other plant in your garden. To treat a lawn burnt from fertilizer, you need to do the same kind of fertilizer leaching as you would in your garden. However, it can be much harder to deliver an even amount of water to your whole yard. If a small area is damaged but the rest seems okay, focus your efforts on that area first.

Flood the lawn area with a soaker hose or sprinkler, but make sure to remove it before the ground gets boggy. Repeat every few days until the plants appear to be recovering. There's always a risk of killing plants when you overfertilize, so even the most intense leaching efforts could be too little, too late.