How to legally feed your lawn and still protect the bay

Summer feeding a really bad idea for fescues

Glenn in Manassas writes: “I applied fertilizer to my fescue lawn a couple of weeks ago, right before it was supposed to storm. It did not storm. Now I have huge yellow spots in my back yard. Will my grass eventually grow back in those spots or do I have to start from scratch this fall?”

It’s likely that you’ll have to spread at least some fresh seed, Glenn. Fescue grasses have many advantages, but they are clumping grasses that can’t grow sideways to fill in dead areas. I’d be out looking for matching seed right now so you can at least try and repair those spots between Aug. 15 and the end of September. Make sure the new seed matches your existing still-alive grass or you’ll have a patchwork quilt out there.

But more importantly: Upcoming storm or no storm, cool-season lawns such as bluegrass and fescue should never be fed in the summer. They don’t need it, and it can burn the grass. (Oops! You knew that.)

And had it stormed, your fertilizer would have been driven directly into the Chesapeake Bay. Let’s not be like Toledo, where fertilizer runoff made their city water supply toxic and unusable just last week.

Feed your lawn and protect the bay — it isn’t hard to do

When Glenn in Manassas admitted to spreading fertilizer on his (former) lawn in the ill-advised month of July, I asked what he was using on his poor fescue.

In the spring and summer, he replied, he uses a 30-0-3 Weed and Feed. In the fall, the numbers on the bag are 24-25-1. Nice. Both of those 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?

Both of these fertilizers contain way too much nitrogen — three times what your lawn needs. And that second one is totally illegal to use in Maryland or Virginia because of its startlingly high phosphorus content. Phosphorus from fertilizers is what caused last week’s toxic algae bloom that made Toledo’s water undrinkable for several days.

You are not an island. Any chemicals you apply to your lawn will get into local drinking water and further degrade the Chesapeake Bay. 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.”

Your lawn will thrive on a twice-yearly feeding with a fertilizer with label numbers that read in the neighborhood of 10-0-0. Higher numbers are dangerous, unnecessary and illegal.

What about weeds?

Pankaj in Herndon writes: “I have a lawn which is growing flowering weeds in many places. Can you advise me on what to use, how much, and the frequency so that the weeds go away?”

If you must use something directly on lawn weeds, the safest and most effective choice available right now is a relatively new organic herbicide based on a specific formulation of iron. That’s right, iron. Professionals have long known that small amounts of iron can help green up a lawn, but new research has also found that spraying the right concentration and type of iron under the correct conditions will kill broadleaf weeds without harming the grass.

These new iron-based herbicides are available online and at better garden centers. The mail-order supplier Gardens Alive has one called Iron-X. And almost all of the major chemical suppliers (such as Bayer, Ortho and Scotts) have an iron-based product available at retail stores. Look for the active ingredient to be “HEDTA,” “Iron HEDTA,” or “Fe HEDTA.” (“Fe” is the periodic table abbreviation for the element iron, as in the word ferrous.)

Proper turf feeding prevents weeds; overfeeding feeds weeds

The long-term answer to weed control is, of course, correct lawn care. A well-fed, properly-cut and watered lawn will crowd out weeds naturally. And one of Pankaj in Herndon’s responses to my questions about his lawn care practices revealed the cause of his weeds.

“I feed the lawn about five times a year,” he writes — “in April, May, July, September and November.”

Yikes, Punkster. That’s like you or I eating five double cheeseburgers three times a day, every day of the year, except on Sunday when we have six milkshakes, too.

Overfed lawns breed weeds. And that many feedings is now illegal in both Maryland and Virginia. Yes, your lawn does need to be fed — it likes a nice feeding in the fall and a lighter one in the spring. And it loves when you give it regular snacks by returning its nitrogen-rich clippings to the turf.

Feed more often than that and weeds are guaranteed.

Fall lawn care in a nutshell

This was a pretty easy year on area lawns composed of bluegrass and/or fescue. Lots of rain and little heat combined to replicate the conditions of their original home in the United Kingdom and other parts of Europe. (Sorry, but “Kentucky bluegrass” doesn’t come from the same continent as Kentucky; there are no turf grasses native to the U.S.)

This easy summer means there shouldn’t be too much damage to repair, and the lawn owners’ only chore should be to provide a safe, legal feeding for the fall, which means anytime from mid- to late August through September. Be aware that new laws in Maryland and Virginia regulate the amount of nitrogen that can be applied to your lawn and ban the use of phosphorus in lawn fertilizers.

Please follow these regulations. Overfeeding makes lawns weak, and phosphorus from lawn fertilizers is what caused the toxic algae bloom that made Toledo’s water unsafe to drink for several days last week — illustrating clearly that the products we use in our landscapes can have devastating effects on our entire region.

  • The absolute best way to feed your lawn is to have an inch of yard-waste compost applied to the surface and raked in. Try it once and you’ll never go back to explosives in a bag. (See Glenn from Manassas No. 2)
  • Second-best is corn gluten meal applied at a rate of 9 to 10 pounds per thousand square feet of turf. Bonus: Apply it next week and you’ll feed the lawn and inhibit the germination of cool-season weeds, such as dandelion and clover.
  • Third-best is a bagged organic lawn fertilizer with label numbers of or around 9-0-0. If you want it to be really, most sincerely organic, look for the OMRI symbol, indicating the product is listed by the Organic Materials Review Institute, which is the equivalent of the USDA Certified Organic label on food.
  • If you must use chemicals for some reason (“the heck with the Chesapeake; I never liked it that much anyway”), use one with the lowest possible NPK numbers on the label. And remember that in Maryland and Virginia, the middle number on the bag, indicating the phosphorus content, must be zero. Lawns don’t need phosphorus, a noxious water pollutant. And any lawn fertilizer containing phosphorus is now illegal to sell in those states.
  • Or ignore all this common-sense advice, burn out your lawn and then see if the National Guard will bring us all water like they did in Toledo last week. Because, despite assurances that “it couldn’t happen here,” D.C. water authorities recently acknowledged that they test for similar toxic algae blooms weekly.

Find more information about Maryland’s fertilizer law here.

Related Stories:

Follow @WTOPLiving and @WTOP on Twitter.

More from WTOP

Log in to your WTOP account for notifications and alerts customized for you.

Sign up