He's back - the ever-popular guru of gardening, Mike McGrath. Mike's the former editor of Organic Gardening Magazine, host or visiting expert on numerous TV shows, and now star of his nationally syndicated radio show, You Bet Your Garden, which airs locally on WTOP every Saturday morning. He spoke to customers recently as part of our Urban Gardening Weekend and here are the highlights. His lawn advice applies to cool-season grasses, like bluegrass and fescue, not to the warm-season turfgrass zoysia.
- How to mow? Always with a sharp mower. Dull blades cause injury to the blades that does not repair itself. And don't mow during droughts - that just encourages weeds by exposing more soil to the sun. Most important of all, mow high - 3" in the sun and 3.5" in the shadier spots.
- Mike loves minor bulbs planted in lawns and told a funny story about them - that the Dutch introduced them in the U.S., thinking that we were tired of our green lawns and would want some color in them. Turns out, Americans really love their lawns green - all the time. (I've tried planting small crocuses in my lawn and loved the effect!) When asked about bulbs that don't come back the next year, Mike responded that that's usually because those bulbs don't like all the feeding and watering we're doing to our lawns. So if your lawn gets that kind of attention, it's best to dig up the bulbs for the summer. You can just put them in a pot in the basement and leave them unattended until fall, when it's time to replant them.
Japanese BeetleWhat to do about them? They breed in turfgrass, so our lawns suffer from grabs eating the lawn roots, and then the adults damage our roses. Interesting factoid: Japanese beetles aren't much of a problem in Japan because few Japanese gardens include lawn. In fact, in Japan the beetles are considered a sign of good luck. So, lucky us.
One way to avoid beetle damage is to cut the lawn 3" or higher and keep your lawn relatively dry. (The grubs just love daily watering!) But most effective of all is to treat your lawn with milky spore powder in late summer, making sure the soil is 70 degrees or warmer. That'll immunize your lawn against Japanese beetle grubs for years.
But don't apply milky spore now - it's only effective when the grubs are eating, in late summer. So until then when you can prevent the grubs occurring next year, Mike recommends cutting down all your rose blossoms at the first sign of the beetle (and that's the only thing he recommends using the traps for - to alert you to the first beetle's arrival). Then take down the trap and cover the roses with a floating row cover for 10 days. The beetles won't hang around, so you can remove the row cover and enjoy your reblooming roses the rest of the season.
Organic sprays like Neem-oil products, which deter feeding by the beetles, are effective for 3-4 days, so need to be applied frequently.
- Weed fabric? Mike thinks they were created just so weeds would grow really well.
- What about raised beds for growing vegetables? Mike's very pro-raised bed because if you grow vegetables on flat soil, alongside your lawn, the lawn will invade your veg beds and the lawn will prevail. To build up the soil inside the raised beds he recommends placing cardboard on top of the lawn, then good soil.
- Fertilizing lawns. Turfgrasses really suffer in our summers (they'd rather be back in England where they came from) and the worst thing to do in the summer is to feed the lawn - it'll just create bare spots. Feed in the spring when the forsythias come into bloom with corn gluten meal, which is 8-10 percent Nitrogen and also acts as a pre-emergent weedkiller. Corn gluten meal contains the "exact right food for lawn". Then leave grass clippings - which contain 10 percent Nitrogen - on your lawn. For that, Mike recommends a mower that pulverizes the clippings (misnamed "mulching mower"). They turn clippings into an imperceptible powder. Clippings also return moisture to the lawn.
Even if you've used corn gluten in early spring and left your clippings on the lawn, your lawn still needs to be fed in the fall (in this region, between August 15 and September 15) and Mike's preferred product is a one-inch layer of good old compost. Also in the fall, aerate if needed, and sow seeds for new lawns or to fill in bare or thin spots (overseeding).
- Synthetic fertilizers Mike considers "fake pee", and he's not a fan.
- During heat waves, let your lawn go tall, which keeps more moisture in the plants. Don't water frequently, which just results in shallow roots, which make the grass less drought-tolerant. Always water deeply, but not frequently (like every day). Weekly is best. (If you cut high and water deeply, turfgrass roots will go down four feet!) If your lawn turns brown, water deeply but don't cut. (And again, don't feed.)
- One audience member asked what to do about a 90-pound dog that's damaging his lawn and Mike had several tips on hand. Get your dog to drink more water - that dilutes the nitrogen in their urine. No, special diets don't really work but flushing the spot with lots of water immediately after your dog has relieved him or herself (and females do the most damage) works well. Mike suggests having a special area of your property where your dog can pee without doing any damage, and then rewarding him or her when they use that spot.
To repair pet damage, in the fall sow some seed of the matching turf type (the same named variety), with some compost. If you don't know the exact variety, bring some into Homestead and get it identified for you.
- Asked about lawn on steep slopes, where mowing can easily scalp the lawn, Mike recommends growing groundcovers that don't need mowing, or creating terraces.
- Got shade? If your don't have at least four hours sun, forget about lawn - grow moss! It's green all year and needs neither feeding nor mowing. Some types can even take a bit of foot traffic. (No touch football, though.) The new fine fescue mixes can take shade, but not much foot traffic.
- To summarize, the "dirty little secret" of lawn care is these 3 tips: cut high, water correctly and avoid summer feeding.
Click here for lots more lawn tips and quips from Mike. That's our summary of his 2010 talk at Homestead. Yes, we try to bring him back at least yearly.