Q. I applied fertilizer to my fescue lawn in the middle of July, right before it was supposed to storm. It did not storm. Now I have huge yellow spots in my back yard. Will the grass eventually grow back in those spots?
---Glenn in Manassas (Virginia)
A. It's likely that Glenn will have to spread fresh seed. Fescue grasses have many advantages—they can take some shade and require less food and care—but they are clumping grasses that can't grow sideways to fill in dead areas, the way bluegrass can. I'd be out looking for matching seed right now, so he can repair those spots during the ideal seeding window of mid-August through September.
And I mean matching seed. As our lawn care guru, Iowa State turf grass Professor Dr. Nick Christians explained to me years ago, you can't buy seed to make lawn repairs based on the type of grass alone. 'Bluegrass isn't always blue', and there are many varieties of fescue. The existing grass in Glenn's lawn may be dark green with blunt blades, while the grass that grows from a bag just marked 'fescue' may be pointy and a lighter color, even though they're both 'fescue'. And if the new seed doesn't match the existing grass, he'll get a patchwork quilt. That's why you should only buy premium named varieties of grass seed—so that you can be sure of getting the same grass again when you need to reseed several years down the line.
But more importantly here—upcoming storm or no storm—cool-season lawns like bluegrass and fescue should never be fed in the summer. They don't need it, and it can burn the grass. (Oh—I guess Glenn knows that now!)
And if it had stormed, almost all of Glenn's fertilizer would have been driven directly into the Chesapeake Bay. This kind of thoughtless use of fertilizer has to stop, or we'll all end up like Toledo, where fertilizer runoff made their city water supply toxic and unusable earlier this month.
And we know for a fact that Glenn used chemical fertilizer. When he copped to feeding his (former) lawn in the ill-advised month of July, I asked exactly what he was using on his poor fescue. In the Spring and Summer, he replied, he uses a "weed and feed" with an NPK rating of 30-0-3. For the fall feeding, the numbers on the bag are 24-25-1.
Yes, those numbers are really high. Here's a little primer on what they mean. Basically, all fertilizers must have three numbers on the label. The first refers to the Nitrogen content, which is the primary food for non-flowering plants like lawns and sweet corn. The third number is the Potassium content. The middle number indicates the amount of Phosphorus—the chemical most often implicated in problems like the toxic algae bloom that made Toledo's water undrinkable and the one that authorities are trying the hardest to decrease. (That's why modern dish washing and laundry detergents say "no phosphorus" or "phosphorus free" on the label….)
There has been a concerted effort to try and lower the amount of 'P' getting into our waterways for quite some time. That's why Glenn's Fall fertilizer—the one with the startlingly high Phosphorus content—has recently become illegal to sell or use in Maryland and his home state of Virginia. New laws now in effect in those states have essentially banned the use of phosphorus on lawns unless a soil test shows the need for it. And even if a test did show low levels, his fertilizer would still be way too full of it. And both of the fertilizers he used contain way too much nitrogen—three times what a lawn needs.
In fact, both fertilizers qualify as high explosives; placed into an artillery shell they would have the potential to do considerable damage. Do you really think it's wise to apply high explosives to the lawn you and your family are walking on?
People need to realize that lawn chemicals don't stay on their lawn; they get into local drinking water, and in Glenn's DC-area case, further degrade the Chesapeake Bay. In other areas, they ruin lakes and pollute rivers. Blame farmers all you want—they do share some of the guilt—but studies consistently show that homeowners apply four times as much fertilizer per square foot as the average farmer. As Pogo Possum once famously said, "we have met the enemy, and he is us."
Now—we are not saying that people shouldn't feed their lawns. These new laws—and similar laws in other states—simply reduce the levels to reasonable amounts. Cool season lawns will thrive on a twice-yearly feeding with a fertilizer whose label numbers read in the neighborhood of 10-0-0. Higher numbers are dangerous, unnecessary and possibly illegal.
Corn gluten meal is right around that number. And there are many other types of bagged organic fertilizers. And lawns love a compost feeding. Safe and sane lawn care just takes a change in attitude—and a desire to do the right thing. If you need an incentive, just 'remember Toledo'. Unless you like toxic algae blooms making your drinking water look like a green smoothie…