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Lawn, Garden & Landscaping

2003-08-01 11:28:00

How do I revive grass damaged by my pets?

: I have two large female dogs. The grass has died in all of their favorite "potty" spots. Is there some sort of chemical that I need to apply to revive this grass? Can I prevent it from continuing to happen?   

ANSWER: Dog urine and feces can be a frustrating lawn care problem. Small amounts may produce a green up or fertilizer effect while larger amounts result in lawn burn or dead patches. While most burn spots recover with time, dead areas can be large enough in some cases to require reseeding or sodding. Homeowners, who are also dog lovers, are presented with a dilemma, particularly when one family member prefers the dog and another prefers a well-manicured lawn.    The presence of urine or feces on the lawn is related to the nitrogen content and concentration of these waste products. Urine, when produced as a waste product in animals, removes excess nitrogen from the body via the kidneys. Nitrogen waste products are the result of protein breakdown through normal bodily processes. Carnivores, including cats and dogs, have a significant protein requirement, and urine volume/production varies due to animal size and metabolism. Urine is a more serious problem for lawns because it is applied all at once as a liquid fertilizer, whereas feces slowly release the waste products over time. Since stools are usually solid, owners have the option of frequent removal. With more time for the waste to dissolve into the lawn, stools that are frequently removed, damage lawns less than urine.   The primary concern from urine damage to lawns is minimizing the nitrogen concentration added to the lawn at any single time. Female dogs, being less likely to urine mark and more likely to squat, are the primary culprits of lawn damage since they will urinate anywhere on a lawn and usually all at once. This results in a single nitrogen dump confined to a small patch of grass. The resulting brown spot often have a green ring around the outside. The nitrogen overload at the center causes the burn, but as the urine dilutes toward the edges, it has a fertilizer effect. This characteristic brown spot / green ring pattern has been called "female dog spot disease" by some horticulturists. As might be expected, lawns most susceptible to nitrogen burns are ones where standard fertilizers are maximized in the lawn. Homeowners making the extra effort to have a green lawn may be quite discouraged by their neighbor's dog damage or their own pet's potty residue. Usually, only the grass blades die and the roots remain intact and will usually grow back in time. However, when the dogs use the same spots repeatedly, which they probably do if they're like mine, then eventually the grass roots will die as well.   Different types of grasses react differently. Kentucky 31 (fescue) and Lolium perrene (perennial ryegrass) are the most resistant to urine effects. In fact, the urine routinely produced a fertilizer effect on these grasses at diluted concentrations. Kentucky bluegrass and Bermuda grass react very sensitively to any urine concentration and severe burn results. Even on the most urine resistant grass, fescue, urine concentration was a bigger problem than urine volume. Concentrated urine with volumes as little as 30cc (one ounce) caused lawn burn even on fescue grasses.   You might check their diet and make sure that they're not getting too much protein (raw meats, etc.). An article I read several months ago also talked about adding tomato juice to the dog's diet or baking soda to it's water.  In addition, if you feed them only once a day, you might break up the feedings into two meals like breakfast and dinner to help dilute the protein. Don't overfeed the animals, particularly prepared people food. Increasing the dogs water intake will help. Also, watering the areas of frequent urination will help to wash-away and dissolve the protein residue.