A tough week for lawns
Mike McGrath, Garden Plot
Meet Mike in Chantilly on Friday, Sept. 23
Mike will give a talk on a timely garden topic, answer all your questions and sign books at 11 a.m., 1 p.m. and 3 p.m. at the Capital Home Show at the Dulles Expo Center in Chantilly on Friday, Sept. 23. Note: The show runs all weekend, but Mike will only be there on Sept. 23.
Can we do anything to our lawns this weekend?
Sue in Sterling asks a question that's on the minds of many: "I was wondering if there's anything I could put down on my lawn right now, as it seems the bulk of the rain has passed. Would this weekend be a good time to do anything to the yard?"
Yes, Sue, it would be a good time to look at it and be thankful it isn't under four-feet of water. Because, unfortunately, while this is one of the best weekends of the year calendar-wise to seed, over seed, core aerate, de-thatch and feed cool-season lawns, it has become one of the worst weekends, reality-wise.
You can't aerate mud. In fact, you'd make the soil worse if you foolishly tried to pull cores out of this sopping wet turf. And even just walking on the grass to spread fertilizer or seed right now could damage the lawn-severely.
The best thing to do this weekend is to plan what needs to be done sometime this fall, like core aeration, the filling in of bare spots and/or giving the grass its biggest feeding of the year. Then arrange the machine rental or get the supplies in hand and hope the ground is dry by next weekend.
Fescue will not beat up Bermuda grass
Stan in Maryland writes: "My lawn has a lot of bare spots, and I want to reseed it with a better grass than my existing one. Will a tall fescue grass seed overtake existing Bermuda or wire grass if I first aerate the turf?"
One word answer Stan: "No."
You want two words? "No way."
The kind of over-seeding you seem to be describing can only fill in bare spots, like the ones that occur naturally in fescue lawns. Because fescue is a clumping grass that doesn't spread, it needs to be over-seeded in the fall at least every couple of years to keep the lawn looking full and lush. Bermuda and wire grass do spread laterally, however, so if you leave them in place, they're the grasses that would win this war, hands down.
Sorry, but it sounds like you need to be prepared to replant that lawn completely during our next dry stretch. Here's the details on how to do just that from a recent series of Garden Plot.
Seeding, aeration, feeding, liming: What's the best sequence?
Anthony in Chantilly writes: "How long should I wait to overseed, lime and fertilize my lawn after I aerate? My soil pH is six to six point five."
First, don't work in wet soil, Anthony. When it finally becomes nice and dry a good six inches or so down, do the core aeration first. Then you can immediately spread an inch of compost over the lawn, rake the new seed into the compost and begin a regimen of gentle watering (unless it rains). No fertilizer. You need the compost to create your new seed bed, and compost is better food for a lawn than anything in a bag. And chemical fertilizers actually stress new grass seed; so-called 'starter fertilizer' is a non-starter.
Then wait until the new grass is two-inches high and lightly add a little lime or wood ash to bring the pH up a tiny bit. And I mean tiny and lightly; only use a little bit of either amendment. Your soil's pH is close to normal as it is, and you don't want to push it into the alkaline range.
And if you have the choice, use hardwood ashes from a wood stove or fireplace instead of lime. High-quality wood ash raises soil pH just as well as lime, and supplies lots of essential soil nutrients that lime does not contain.
Overfeeding = Black spot on roses
Dan in Fredrick writes: "I always seem to get a surge of black spot on my rose bushes this time of year. They're on the south side of the house, so they get plenty of sun. I recently fed them with a systemic drench and I used 'shake and feed' earlier in the season."