Fertilizer Burn Signs and Remedies
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Apply the proper mix and amount of lawn fertilizer to avoid fertilizer burn and promote a lush, green, healthy, weed-free turf.
Every homeowner dreams of a lush, green carpet of grass–the envy of the neighborhood. In the pursuit of this perfection, lawn enthusiasts subject their turf to everything from shampoo to beer to fertilizer–the most common additive being fertilizer. Turf fertilizer provides the most cost-effective boost to poor lawns, encouraging turf growth and providing protection from weeds, disease, pests, and environmental factors.
It’s easy for the novice to overuse fertilizer or to apply it incorrectly. The thinking goes something like this: “If a little is good, a lot is better. If fertilizing in spring and fall is recommended, I’ll add summer and winter to the fertilizer schedule just to be safe.” This overzealous approach frequently results in fertilizer burn.
Fertilizer burn is dehydration. Salt buildup from chemicals inhibits the grass blades from absorbing water. The burn results from only one thing: the incorrect application of fertilizer. Severe dehydration eventually kills the grass.
Signs of Fertilizer Burn
Spotting fertilizer burn is easy if you know the signs. If your lawn displays either of the following signs several days after applying fertilizer, suspect fertilizer burn:
• Grass blades turn yellow, brown, white, or tan.
• The lawn displays yellow, brown, white, or tan stripes.
A little knowledge about fertilizer goes a long way toward cultivating and maintaining a healthy lawn and preventing fertilizer burn.
Turf requires sixteen elements to grow. Commercial “complete” fertilizers contain the most important three elements: nitrogen, phosphorus (sometimes listed as phosphate), and potassium (sometimes listed as potash). Lawns often require an annual feeding of these three elements, but nitrogen is the nutrient that depletes the most rapidly. Home lawn fertilizer is available in solid granule form and liquid form. The solid form is better for covering large areas.
Fertilizer labels display three numbers; for example, 10-6-18. These three numbers indicate the percentage of the three essential elements. A fertilizer with a mix of 10-6-18 means that it contains 10% nitrogen, 6% phosphorus, and 18% potassium. Nitrogen supplies the green to the lawn, phosphorus feeds the roots, and potassium promotes the overall health of the lawn. Home lawn complete fertilizers contain slow-release nitrogen, fast-release nitrogen, or a combination of the two.
A combination of slow-release and fast-release nitrogen is best. The fast release nitrogen greens the lawn quickly, in approximately three to five days. The slow release nitrogen maintains a green lawn by providing nitrogen at a constant rate.
Tips for Avoiding Fertilizer Burn
• Fertilize in spring and fall, not in the middle of summer. Summer heat contributes to fertilizer burn and encourages weed growth rather than turf growth. The best time to fertilize varies by location. Check with your local lawn-care center for the best window of opportunity in your area.
• Perform a soil test to determine lawn nutrient deficiencies every three to five years. You may need to apply lime instead of, or in addition to, fertilizer.
• Buy quality fertilizer. Select the best fertilizer mix for your turf. Ask your lawn-care center for help, and be prepared to tell them how many square feet you need to fertilize. You may only need to apply nitrogen instead of a complete mix. Applying nutrients that already exist is not only a waste of money, but it results in the salt build-up that contributes to fertilizer burn.
• Select a fertilizer with a combination of slow-release and fast-release nitrogen.
• Apply fertilizer to dry turf. You can safely apply fertilizer to slightly damp soil if you do not see or feel any droplets of water on the grass.
• Use a spreader to apply solid fertilizer. Attach liquid fertilizer to a hose. Follow the instructions to ensure proper calibration for solid granules or proper rate of flow for liquid fertilizer.
• Apply fertilizer at half the recommended rate. Make the application in one direction, barely overlapping with each pass. Make the second application at right angles to the first application, in a grid pattern. This method takes twice as long, but it helps avoid striping the lawn.
• Open the spreader only after you have started walking, and close the spreader before you stop walking.
• Never apply more fertilizer than the manufacturer recommends.
• Water the lawn well within 24 hours after applying solid fertilizer.
Note: Whenever you work with chemicals, take appropriate precautions. Cover your body and hands, and wear a dust mask. Keep pets and children away for 24 hours.
Surviving Fertilizer Burn
If you even suspect that you may have applied fertilizer incorrectly, you can try to remove the excess fertilizer and then water the lawn to dilute the chemicals. If you accidentally dumped fertilizer in a localized area, use a wet/dry vacuum cleaner to remove as much as possible before watering. If you applied massive amounts of fertilizer to the entire lawn, attach a bag to the mower and try to “vacuum” the lawn before watering.
Water until the ground is thoroughly soaked, and then water again. Water the lawn every day for the next few days. If you catch your mistake in time, you can reverse the conditions before any significant damage occurs.