Why Overfertilizing Harms Your Lawn

A Lawn Care Don't!

The old saying, "the more, the better," does not apply to lawn fertilization. Fertilizer is a plant's food, so twice as much is not twice as good. Rather than providing too much fertilizer to a lawn, the trick is putting down the correct amount of fertilizer so healthy, green grass grows in your yard. This article will explain why overfertilizing harms a lawn and how to avoid the resulting problems by applying the correct amount of fertilizer.

Overfertilizing Outcomes

Unless designated as slow- or time-released, fertilizer provides nitrogen and other nutrients to the grass very quickly. Putting down more fertilizer than required means that the grass will get excessive amounts of nitrogen and other nutrients at the time of application and no nutrients when the plants need them later on. Think about overfertilizing like a buffet. If all the food for the week is put out on Monday, we will get our fill that day, but by the end of the week, we'll be very hungry.

Overfertilizing results in numerous negative consequences, most of which center on extra mowings because more fertilizer means that the grass grows faster. Following are examples of problems that may result from overfertilizing:

• Weed encroachment: When your lawn grows quickly after overfertilizing, you will need to mow more often to follow the one-third rule (never cut more than a third of the leaf blade off during any single mowing). As a result, overgrowth or scalping may occur, allowing weeds to invade the lawn.
• Excess clippings:  A mulching mower is usually powerful enough to handle a lawn with excess growth. But, if you don't have a mulching mower, you may have to go over the lawn twice and run the risk of smothering it with heavy clippings. If you typically bag your clippings, you will have more to bag.
• Turfgrass diseases, such as brown patch and pythium: Both of these diseases are fungi born and occur in warm, moist and overfertilized conditions.These diseases can be devastating to a lawn and may require a fungicide to control them.
• Burning or bleaching: In extreme overfertilization situations (five to 10 times the recommended application rate), the grass will turn a straw or tan color and the blades will burn from the tip down. Once this occurs, the existing grass cannot be salvaged, but trust that new grass will eventually replace the burned or bleached grass. This scenario is more likely to occur when temperatures are not conducive to grass recovery (mid-summer for cool season grasses and fall for warm season grasses), but can happen at any time if the over-application is great enough. This problem occurs because the fertilizer in the soil cannot be neutralized or easily removed.

One of the great blessings that can occur after overfertilizing is a heavy rain downpour that may flush the nitrogen away from grass roots. If possible, a heavy dose of water from a hose or irrigation system can help as well.

Finding a Fertilizer Fix

Rather than overfertilizing, put down small amounts of fertilizer throughout the season. The easiest way to fertilize correctly is to follow the label on the back of the fertilizer bag. This printed rate of fertilizer comes from years of research and testing from the company and independent laboratories. If the bag does not have any directions or guidelines, simply move on to a brand that does. The extra few dollars you may spend will be worth the peace of mind knowing you have applied a proper amount of fertilizer.

To avoid overfertilizing, buy a slow- or timed-release fertilizer. These fertilizers provide consistent, long-term nutrients to the grass. They cost a bit more, but will save money and time in the long run through fewer applications.

Fertilizer application equipment can also help achieve this same type of light, frequent feeding. For instance, fertilizer irrigation systems (fertigation) are very effective and relatively inexpensive. Another good investment is a high quality rotary spreader (look for one that is sturdy with large, wide wheels). A rotary spreader reduces the chance of skipping certain areas or overapplying, particularly compared to a drop spreader.

Last, keep a proper feeding schedule. For cool season grasses, this schedule revolves around four holidays: Memorial Day, Independence Day, Labor Day and Thanksgiving. For warm season grasses, fertilize around the first three holidays, but omit the Thanksgiving feeding.

Ready...Set...FERTILIZE!

Since fertilizer is your lawn's food, provide some portion control. Use the guidelines above to create a proper fertilizing regime, rather than overfertilizing. Soon enough, you will be a fertilizer pro.

For more detailed information about proper fertilization techniques, read the article "Feeding Your Lawn".