You Might Be Fertilizing Your Lawn Too Much: How To Save Your Grass

In the effort to create a lush, healthy lawn for the summer, many gardeners can end up killing their grass with kindness. While the right fertilizer at the right time in the right dosage can produce great results, showering your plants with nutrients is a bad idea. Not only is it expensive and often unnecessary, but it can cause serious harm to your grass, even potentially killing it.

If you've noticed your grass burning up in the summer heat, for example, fertilizer might be the culprit more so than the sun. The most common sign of an overfertilized lawn is brown or yellow patches. That browning is caused by the excess salts from fertilizer burning the roots. If you used a spreader, you might see strips of browning turf where you overlapped, causing certain strips to receive a double application of fertilizer. If you applied by hand, the brown spots might look patchier and less consistent.

If you don't notice these signs of fertilizer injury, you should still check for subtler signs that you're using more fertilizer than you need. Even without visible root burn, heavily fertilized lawns are vulnerable to pests like aphids and mites. These common garden pests are especially fond of tender, new grass, and heavily-fertilized lawns will be putting out tons of lush growth in response to the flood of nitrogen and other nutrients. In either case, there are plenty of ways to treat a lawn that's already been over-fertilized and prevent it from happening in the future.

The standard advice if you've already applied too much fertilizer to your lawn is to water heavily. That means saturating the lawn with one inch of water in a single irrigation session. Repeat that three or four days in a row or up to a week straight to help flush the excess fertilizer out of the root zone. If the browning patches were still alive when you started that watering regimen, you should notice them begin to green up again within a few weeks.

If they don't green up, they're likely dead. In that case, overseed the dead patches with new grass seed. However, be cautious about using any seed starter fertilizer. There might still be leftover nutrients from the excess application that killed those parts of the lawn, so adding additional fertilizer when overseeding could put you right back in the same scenario all over again. You can either skip the fertilizer altogether to be safe or get a soil test to figure out exactly which nutrients you might need to add when overseeding and which ones you should avoid because levels are already high.

In milder cases where fertilizer didn't burn the roots but has attracted pests, resist the urge to use pesticides. Instead, hold off on future fertilizer applications and monitor for signs of severe damage. Healthy lawns — that aren't over-fertilized or over-watered — can tolerate some level of pest infestation without serious injury.

After treating an overfertilized lawn, the next thing to do is get your game plan ready to avoid making the same mistakes when fertilizing your garden next season. The simplest way to avoid the problem is to stop fertilizing your lawn altogether. While treatments can make it look greener and lusher, it's not really critical to your grass's survival. If you want a picture-perfect carpet of green, you may need fertilizer, but probably not as much as you think. You can reduce those needs even further by building long-term soil health to reduce your lawn's dependence on fertilizer.

To do that, get a mulching lawn mower that will shred grass clippings and leaves into your lawn. Letting this organic matter break down in place returns the nutrients in that debris to the soil. This step alone can extend the results of each fertilizer application, allowing you to go longer between treatments. In lawns where clippings are regularly removed, the rich green color produced by a nitrogen-rich fertilizer begins to fade after about four weeks. When clippings are left in place, the color can last up to eight weeks.

If you do fertilize your lawn, choose a slow-release formula, which is less likely to burn roots. When in doubt about how much and which nutrients are needed, a soil test is your best bet. If you don't want to bother with that, opt for the minimum recommended application rate on the package — or even less — and make sure to water thoroughly both before and after.