The nationally famous gardening guru Mike McGrath talked about "How to Get your Lawn Off Drugs" yesterday at Homestead, then stayed to answer tons of questions. Here's my report of the wit and wisdom of Mike McGrath, which report has approved by Mike (okay, after a couple of edits).
As a preface, everything here refers only to cool-season grasses like bluegrass and fescue, not to the warm-season turfgrass zoysia. And by the way, Mike made sure we understand that zoysia means having a dormant, straw-colored lawn for almost 10 months a year.
The Pro-Lawn and Anti-Lawn Extremes
To people hoping for an Augusta-quality lawn, Mike says to "Get a life. Find something more interesting to do." And to the anti-lawn crowd he says not to worry - lawns can be "very ecologically sound and stable, and they sure handle stormwater better than concrete." The big problem with lawn isn't the plant itself but overfertilizing and dumping totally unnecessary chemicals on them. As for alternatives like meadows or native grasses, he says he's a realist, and nothing beats turfgrasses for play. And if you think lawns are a lot of work, think again. Mike calls turfgrasses easy plants that grows themselves and if your lawn doesn't look good, you're responsible.
Raise That Mower!
The number one key to a good lawn is to mow it high - 3" in the sun and 3.5" in the shade. The notion that if you scalp your lawn short, the result will be fewer mowings just doesn't work because mowing short just encourages growth - and it's uneven, ugly growth at that. (Grass cut high grows at one-half to a third the rate that closely cropped grass grows.) Cutting grass short causes grass to go into shock because it's removing the foliage they need to get energy from the sun. Mowing high is your best protection against weeds because it shades their seeds and prevents most of them from germinating.
Oh, and don't trust the setting on your mower (Mike doesn't). Actually measure the height after you've mowed to make sure it's really 3" or higher. Some mowers are helpless, though - with the highest setting at less than 2 inches.
Crabgrass is just waiting to take over, but you don't have to let it if you apply a layer of corn gluten meal in early spring. It's a part of the corn plant and is used in animal feed, so it's organic and totally safe. It not only prevents germination of weed seeds (actually, ALL seeds) but it's the perfect fertilizer for your lawn, at 8 to 10% nitrogen. Yes, the true Weed & Feed! If your lawn is "ratty" he recommends applying 20 lbs per 1,000 square feet, and half that if your lawn is reasonably thick. The only time it works as a crabgrass preventer is in early spring and he recommends doing it when the forsythia and redbuds first bloom.
Feeding the Lawn
Organic gardeners will love this quote from Mike: "If you've been on the Scotts 4 program, you need to get into a 12-step program." Mike also had plenty to say about chemical fertilizers, like "American lawn food is a high explosive." And that's actually true - the same ingredient was once used to blow up a Federal Building.
Mike says that industrial fertilizer was never needed, but business owners turned to fertilizer production to keep their munitions factories going after the war. But now let's get to the alternatives to industrial fertilizer.
Even if you've applied corn gluten meal the spring, a fall feeding is still essential and for then, compost is the ideal. (That means the end of August through September. And never feed your lawn in the summer when it's dormant and wants to stay that way. "Scotts Summerguard only guards Scott's profits. Its' death to lawn.") If you use compost, he recommends a 1-inch layer, and gives a big thumb's up to Maryland's own bagged compost product, Leafgro.
Organic matter was a big theme in Mike's talk, and here's why: "Our lawns are starved for organic matter". But that's where compost is so great - after applying it for 5 years, the structure of your soil will have changed dramatically - with better drainage, more microbial life, and a healthier lawn.
Mulching mowers are also terrific for the lawn, pulverizing the clippings and depositing them on the lawn where they'll supply an excellent 10-1-1 fertilizer (that's a higher percentage of nitrogen than horse manure at 6%). In fact, clippings from a mulching mower can supply half the nitrogen your lawn needs all year. In fact, Mike says if you mow high with a mulching mower your lawn will definitely look better than if you followed Scotts's advice and fed four times a year.
And what about chopped-up leaves as lawn fertilizer? Yes, they provide even more nutrients and organic matter and it's really easy to do. Instead of raking and collecting the leaves on your lawn, just mow 'em. However, whole leaves will smother your lawn.
Seeding or Reseeding
"Grass seeding in spring is a "chump move" - because the soil has to be 65 degrees (and not just on the surface but several inches below), so seed applied in spring usually sits on the soil for a month or so feeding the local vermin or going stale. Then by the time the new grass emerges, it isn't long before the summer heat hits them. In early fall, bluegrass and other cool-season grasses will sprout right away and have plenty of time to put down roots before the heat comes the following summer.
But first, does your lawn need reseeding? Mike says "You should never have to reseed a lawn in the sun because "all sunny lawns will fill in their bare spots." The clumping grasses we grow in the shade won't do that, so in shade you need to overseed every fall (again, late August through September).
Can you feed and seed? Definitely. Just apply the compost, seed on top of it, then rake and water.
If you water correctly, the roots will go down four feet (!), and correctly means a long soak of about an 1 inch per week. The reason is that "plants are lazy" - they won't send roots deep down into the soil unless they have to, so frequent, brief waterings only make the roots more vulnerable to drought. So letting grass dry out between waterings results in the best root growth. "Be mean, be cruel to your lawn and it'll have a huge root system that can get to water that's deep in the soil." Watering every day? Terrible.
And what about mid-summer drought? "The best thing you can do for your lawn in mid-summer is to go away." Ouch! Asked how long turfgrass can survive without watering, Mike's encouraging answer is: six weeks. Okay, then.
Mike says sure, if you've everything else and your lawn still needs help, rent a core aerator. (Save your money on those "aerating sandels" because they don't work.) Soil compaction is a frequent cause of poor lawns (second only to mowing too short).
What about "Smart Seed"?
Mike's heard of this product and says it's "absolute nonsense." Buy high-quality named varieties of seed - fescue for shade and bluegrass for sun.
If your soil is sandy Mike will congratulate you on not having clay soil, which is much worse, but because sandy soil does needs organic matter, do two appklciations of compost every year.
Lawns don't need lime every year, and Mike recommends it only after a soil test proves it's really needed, and to avoid making your soil too alkaline.
Protecting the Bay
Corn gluten and compost are safe for our waterways because their nutrients adhere to the soil.
Peatmoss is a pH adjuster, so Mike applies it around his azaleas, with compost. It's not a source of nutrients, and there's no benefit in mixing it into the soil. Asked if peatmoss is harvested unsustainably and should be avoided for environmental reasons, Mike assures us that Canadian sources are well managed, unlike some discredited sources in Europe.
Moss is a sign of several things: your soil has bad drainage, the soil is probably too acidic, and you have shade. Solutions are to increase alkalinity, prune for more sun, and improve drainage with organic matter.
Dog urine burns lawns because it's a highly concentrated form of nitrogen, but you can reduce the concentration by letting your dog out more frequently or getting your dog to drink more water. It's also a great idea to flush your dog's chosen site with water immediately after he does his business.
Mike considers compost tea "good fun" but because it doesn't add organic matter to soil, compost itself is better.
Thatch build-up is caused not by leaving grass clippings on the lawn but by overfeeding with chemical fertilizer, so the solution is simple: Stop doing that.