A better looking lawn in just 1 week
John up in Millersville emailed me back in June to report a brown lawn that he thought was due to his “sandy soil.” I asked him a bunch of questions and was shocked to learn that a Glen Burnie hardware store that’s part of a national chain had told him to use — and sold him — a fertilizer with a nitrogen number of 30 on the label.
That’s three times the legal limit for lawn fertilizers in Maryland or Virginia and one big reason his lawn turned brown. I repeat: High nitrogen lawn fertilizers are illegal in Maryland and Virginia, and they’ll turn your lawn brown.
I advised John to yell at the store, stop spreading high explosives on his grass, cut it higher and water it less often but for longer periods of time. His irrigation system was watering for an hour at a pop three times a week, which is a recipe for the kind of stunted root system that also leads to brown summer lawns. Deep roots from long but infrequent watering can store lots of moisture to keep a lawn green during hot summer days.
One week later he emailed back to say that he had raised the blade on his mower, was watering for much longer periods of time less frequently and it looked better already.
This summer especially, the best thing you could — and still can — do for your lawn is never cut it lower than 3 inches. And when you water, water deeply.
Time to prepare for lawn repair
John up in Millersville made his lawn look better in one week with a higher cut and deeper watering. And he knew that we were rapidly approaching the ideal time for full scale repair. Here’s John’s plan:
- Get a truckload of compost delivered and spread it over the front lawn about half an inch thick.
- Over-seed in late August after letting the compost settle for a week or so.
- Temporarily adjust the irrigation to more frequent and lighter watering to get the seed germinated.
That’s a pretty good plan, John. Late August through early September is the perfect window to establish a new cool-season lawn (or repair an existing one) with seed. The warm soil insures fast germination and the cooler fall weather that follows mimics the climates these grasses are native to.
Just be sure the new seed matches the old grass in color and blade shape or you’ll get a patchwork quilt!
Prepare now to save your lawn this “fall”
Many people try and fix their lawn in the spring, which is a great time to lay new sod, but a terrible time for seeding and physical fixes if you have a cool-season grass. Ah, but cool season grasses like fescue and bluegrass respond brilliantly to seeding and physical fixing in what I like to call “the fall,” a time period that is actually the weeks immediately preceding the start of fall; that perfect window of late August through mid-September.
This is the only safe time to core aerate a cool-season turf; removing plugs to relieve the soil compaction that stunts so many local lawns. The soil is too cold and wet in the spring — and the lawn can’t repair the damage once summer heat hits.
It’s also the ideal time to dethatch — removing the browned out stolons caused by overuse of chemical fertilizers. That’s right — thatch is caused by overfeeding, not by leaving your clippings on the lawn.
And pre-fall is also when cool-season lawns respond best to feeding. A top dressing of compost is the ideal lawn food. But corn gluten meal or an organic fertilizer labeled for use on lawns will also provide a gentle but highly effective feeding.
Sucker punched by an unexpected spraying
My heart really goes out to Josh in Annapolis. I would be furious if anything like this happened to me. Heck — I’m furious that it happened to him!
He writes: “I am deeply upset about what happened to my lawn yesterday. The arborist that I contract to treat my trees and shrubs with horticultural oil mistakenly sprayed my lawn for ticks with bifenthrin. I try to maintain a chemical-free lawn and garden to provide a safe environment for my family and all of the beneficial critters. Obviously it doesn’t even make sense to spray a lawn for ticks because I know that’s not where they live. But that doesn’t change the fact that my lawn has been doused with poison.”
No, but it’s an important point to hammer home in a world where useless chemicals are being perfidiously peddled to people who fear ticks, mosquitoes and the like. Yes, ticks are dangerous, but the least likely place to find them is on a lawn.
Ticks lurk in damp, brushy areas where they climb up on tall plants and wait until something brushes by that they can attach to. If you find a tick on a lawn, it probably just fell off you or your pet and is running for the nearby weeds as fast as its eight nasty little legs can carry it.
What to do when you’ve been sprayed
Josh continues: “I have kids — all under 5 — that I do not want to be exposed. What can I do to restore my lawn for the safety and health of my family? Do I need to just wait it out? If so, for how long? And what do I need to do for my plants and lawn now that the beneficial insects have been decimated?”
Well, my normal advice for chemical contamination is to overwater the area to try and wash some of the pesticide off. But two problems with that in this situation:
- Bifenthrin isn’t very water soluble.
- If it was, it would be deadly to the aquatic life that’s never far away in Annapolis. In the pyrethroid class of insecticides, it’s also highly toxic to insects and cats.
Classified as a “possible human carcinogen” by the Environmental Protection Agency, the biggest risk is through ingestion. So don’t eat any garden crops that might have been sprayed. Pull flowers off nearby plants to protect bees and other pollinators. Keep pets, especially cats, who are extremely sensitive to this class of chemicals, off the lawn, as cats and dogs often love to chew on grass.
As for the kids, there will be less and less potential chemical on the actual grass as it grows and is cut. After an entire growing cycle the chemical will remain, but it’ll all be bound up in the soil. The new grass should not absorb it systemically. So just keep the kids off the lawn for awhile to be super-safe. Maybe this would be a great excuse to put up a big sandbox in the backyard where they can play without any worry.
The Bio Integral Resource Center (BIRC) in Berkeley, California, is the common sense expert source when it comes to pest control problems, so I also asked long-time BIRC Director Bill Quarles, for his thoughts:
“The half-life, the amount of time it takes the concentration of the chemical to decrease by 50 percent, in soil is 106 to 147 days in sunlight, but it could take up to 345 days in some types of soil. So bifenthrin is hard to get rid of. It is destroyed slowly by sunlight and microbes, but it’s hard to wash it out because it is insoluble in water and binds to soil.”
The good news here is that most of it will be in the soil and not on the actual grass — so keep your lawn cut good and high. Bill also had an unusual but brilliant suggestion to move things along: Because microbes break it down faster, top dress the lawn with compost “to increase the microbial concentration in the soil and help with faster destruction.”
And top dressing with compost is the perfect food for lawns. Sounds like a plan to me. Oh — and send the bill to that arborist.
Find the official fact sheet on bifenthrin here.
Mike McGrath was Editor-in-Chief of ORGANIC GARDENING magazine from 1990 through 1997. He has been the host of the nationally syndicated Public Radio show “You Bet Your Garden” since 1998 and Garden Editor for WTOP since 1999. Send him your garden or pest control questions at MikeMcG@PTD.net.