LESLIE: Well, weeds are the scourge of those of us who are trying to maintain a pristine lawn. But before you try to wipe them out, stop and listen. They might actually be telling you something.
TOM: Well, that’s true. Weeds contain clues for their own demise: information you might need if you want to address the root problem and keep them from coming back, once and for all. Here to tell us how you can take your turf back is This Old House landscaping contractor Roger Cook.
ROGER: Thanks for having me.
TOM: So, Roger, you’re like the weed whisperer, right?
TOM: You’ve got to read those weeds and let us know what they’re telling us about our lawns, right? We really can get some clues from the type of weed that hits it.
ROGER: We can. But the first thing I want to start out with is: every lawn has weeds.
ROGER: And a minimum amount of weeds isn’t a bad thing. It only becomes a problem when they overtake an area. So, a little weeds is OK, alright?
TOM and LESLIE: OK.
LESLIE: Now, I feel like the internet has become such a huge tool for me when it comes to diagnosing things that are going on in the yard. Because if I see a weed growing in the lawn, I’m not going to know that it’s crabgrass or if it’s whatever. I’m going to look at it and then look online and be like, “Oh, crabgrass.”
So once you identify, say, crabgrass, what do you do?
ROGER: You can’t treat anything until you know what it is.
ROGER: Crabgrass is caused by a couple things: usually an injury to the lawn from a plow or a lawn-mower blade cutting too short or a drying-out of an area. Any area that faces south or southeast and has a lot of gravel or sand underneath it dries out very quickly. A regular lawn with bluegrass and fescue can’t stand up to that and it dries out. And that’s where crabgrass thrives: in those real hot areas. And it gets …
TOM: Now, we could actually be causing that problem if we cut our lawn too short, right? People think if you cut it too short, you’re going to have to cut less frequently but you’re really opening yourself up to a whole bunch of weed problems.
ROGER: The worst thing you can do for a lawn is to cut it too short. It likes to be left – 2½ to 3 inches is a general rule so that it shades itself out a little bit. And by having that shade there, it actually stops some of these weeds from germinating.
TOM: Alright. Here’s another weed that’s an issue in a lot of parts of the country: common plantain. What causes that?
ROGER: It’s a weed that grows in really damp, wet areas. So it’s telling you A) that you’re getting too much irrigation there B) the soil is really heavy and it’s not draining properly. So if you can improve the drainage through aeration – or just adjust the sprinkler system.
LESLIE: Now, here’s a weed that has a funny name, because I thought this was just my son crawling around the house. But there’s one called “creeping Charlie”?
ROGER: Yep. It’s a weed that we find when you have a lot of shade. Tough thing for a grass to grow in. Our regular lawns, they don’t like shade.
ROGER: And once something gets weak, a weed comes in. There’s a weed for every spot: too dry, too hot, too wet, too shady. A weed loves that, not your lawn.
One of the other things – one of the best things you can do for your lawn is to get a soil test done. Because very often, if the pH is off or the fertility is off, it’ll help these weeds to grow in.
TOM: So, really, the weeds are talking to us and telling us something’s wrong with the lawn. So, aside from determining what weed it is, it really is a clue to a bigger problem. And getting a soil test can really provide a lot of information.
ROGER: Right. Knowing what the weed is, knowing what your soil is telling you, you can have a good, strong lawn without doing a lot of spraying of different herbicides.
LESLIE: Mm-hmm. And since I like to do my investigative research online, is there a good resource for me to sort of look up pictures of what I might be seeing on the lawn?
ROGER: Most of the local nurseries will help you out if you bring in a sample in a bag and say, “What’s this? What’s this?”
ROGER: But the National Gardening Association has an online weed library. I read it all the time.
TOM: A weed library.
ROGER: A weed library.
LESLIE: It’s fascinating.
TOM: Alright. Roger Cook from TV’s This Old House, thank you so much for stopping by The Money Pit.
ROGER: It’s a little scary that I know about the weed library.
TOM: Yes, it is a little scary.
ROGER: Thanks for having me.
LESLIE: Alright. Well, you can catch the current season of This Old House and Ask This Old House on PBS. For local listings and step-by-step videos of many common home improvement projects, visit ThisOldHouse.com.
TOM: And This Old House and Ask This Old House are brought to you on PBS by The Home Depot. More saving, more doing.