The Right Time to Grow a Weed-Proof Lawn

    Listen 00:53:13

    Sowing seed at the wrong time of year may be the biggest cause of weedy lawns. Mike McGrath, host of You Bet Your Garden, will reveal that the timing is now right to correct past mistakes and establish a truly weed-proof turf. Plus: answers to all your growing questions.

    Photo: Dave Meier via

    Question of the Week:

    “We removed our entire front lawn this spring when we had our gutters routed underground to carry rain water further away from the house. (It wasn’t much of a lawn; riddled with weeds and very uneven.) We re-planted using a “Pennsylvania Mix”, “Grass Seed Accelerator” and “lawn starter soil”, and now have quite a few weeds. My husband wants to treat the lawn to eliminate the weeds. In scouring your A-Z Garden Answers section I see that proper cutting height, wise watering, and corn gluten are the best defense against weeds in a well-established lawn. But our lawn is still in its adolescent phase, hopefully on its way to becoming well-established, but not there yet. I have been hand-pulling a LOT of weeds and trying to persuade my husband to NOT use chemicals. What do you suggest?”

    — Gretchen in Bethlehem, PA


    Learn more about growing grass near trees »

    Highlights from show:

    Beetles Eating Eggplants

    Andy runs an organic garden for the Springhouse restaurant, a high-end mixed-cuisine restaurant on Lake Martin in the town of Equality, Alabama. Now, he’s recently had a problem with beetles eating his eggplants, and he wants to know of any organic methods of pest control. Mike recommends using row covers for these plants, which completely protects these plants from insects, but allows them to get the sun and air that they need. Mike also recommends for the eggplants that he ask the grower to hold on to the eggplant plants until they’re about eight to ten weeks old, so that they have plenty of biomass, and so that they’d have better luck standing up to these flea beetles. Mike also suggests growing them under those row covers, at least until the flowers form, removing the cover to allow the plants to pollinate. He also mentions an old “Italian trick,” dusting the leaves with wood ash. Even more effective than that would be DE, or Diatomaceous Earth, which is very sharp on the molecular level, keeping the beetles from landing on the leaves. Finally, get a hose with great water pressure, and a nozzle that has a very intense pressure release. Cradle the plant in one hand, and blast off any insects on the plant with sharp streams of water. “Water is the best insecticide.”

    Aphids in the Greenhouse

    Tom in Oklahoma City has aphids in his greenhouse! The aphids overwintered in the greenhouse and they destroyed all of his plants. Mike recommends that Tom close up his greenhouse, since it’s too hot to grow anything in there, then just allow the hot Oklahoma sun to cook anything in the greenhouse. Now, when the time comes to bring the plants in, set up three stations: pot up the plants. Then take those potted plants over to the hose. Cradle the plants and spray them with a sharp stream of water, and then put them off to the side, outside the greenhouse. Once you’ve done them all once, bring the hose over to them, and give them all another spraying. Then, after 24 hours, open the greenhouse, and then give them a final spray, including the pot. It’s not a bad idea to wipe down the rim of the pot with a wet rag, with a little bit of vinegar on it, and the outside of the pot. Then, if the threat of aphids ever emerges while they’re in the greenhouse, just pull them aside and do this again to the affected plants. They also sell yellow sticky aphid traps, which work great, not only to trap the aphids, but to tell you which areas of your greenhouse are affected by aphids, and then on a nice day, take them out and hose them down again. In terms of beneficial insects, you can buy lacewing eggs, whose larvae will eat up to 50 aphids a day, and whose adults are beautiful, fairylike insects that are great pollinators, and they’ll lay a whole bunch more eggs for you. “As long as there is pollen and nectar plants in your greenhouse, and as long as there’s aphids, these insects will keep it squeaky clean.”

    Digger Bees

    Yvette from Philadelphia recently bought a new property and noticed that she had numerous holes in the ground, and also bees coming out of the holes! She wants to know if these bees are good or bad, and if they’ll come back. Now, since they nest in the Spring, Mike quickly identifies them as ground-nesting native bees, or “digger” bees, not to be confused with ground nesting wasps, which nest in late summer. These bees are some of nature’s best pollinators, so the best thing to do is to leave them alone. This will ensure that she’ll have the maximum possible number of flowers per plant. These bees are also ephemeral, sticking around only for a few weeks, and then going away. One important distinction is that, unlike non-native honey bees, these bees do not sting, so they are absolutely harmless, and they will come back every year if you don’t mess too much with the landscaping. “You don’t have a problem, you’ve got beneficials.”

    Growing Grass in the Shaded Areas

    Jeff from Nashville, TN has a commercial lawn service and he’s just started feeding and aerating in the fall, and supplementing them with weed and feed treatments in the spring and early summer. Now, he’s been having problems growing grass in the shaded areas, and he wants to know what to do. Mike notes that most of Jeff’s clientele seem to have cool-season lawns. Fine fescues grow much better in the shade than tall fescue grasses, for one. Some are better for dry shade, others are better than wet shade. In a normal situation, where the shade is being thrown by buildings, you want fine fescue in those areas. Feed it less, and water it less, because a grass in “true shade” will use less nutrients, and so if you overfeed or overwater it, you can kill it. Meanwhile, the opposite is true of tree-shade. “Trees are bullies, trees get the first shot.” Mike says to look up at the tree and see how far out the tree branches reach, and the root system of that tree will extent AT LEAST as far out as those branches, sometimes extending as far as three times the length of the branches. That area under the tree should then be designated as an area that needs extra water and maybe extra food in the spring and fall. One more rule for shade-loving grasses is that they need to be cut higher: They need to be three and a half inches high after being cut. If you cut them down to two inches, they’ll die because they don’t get a lot of sun to begin with: they need more surface area to capture more light. Mike also recommends that since they’re clumping grasses, spread some matching seed every year or two. “If you do all those things, you don’t need pre-emergent. The lawn will take care of itself!”

    BTG and Milky Spore

    Stacy from Leesport, PA recently heard about BTG and wanted to know how it compares to Milky Spore. Mike says that BTG is still too new to really know how they compare. Bacilus Thuringiensis Galleriea, or BTG, was put on the market just this year, exclusively by Gardens Alive, and it comes in two forms: a spray form to spray on your leaves which will kill adult beetles as they eat the sprayed leaves, called BeetleJUS on the Gardens Alive website, and a powder form that can be applied to the soil and kill any grubs in the ground, called GrubHALT on Gardens Alive. Now, Milky Spore is also a naturally-occurring soil organism, native to the far east, which is the reason why they don’t have a Japanese Beetle problem in Japan. The primary difference between the two is that BTG will kill the grubs in the ground, no questions asked. Whereas Milky Spore will infect the grubs, turning them into little Milky Spore factories, keeping the organism in the soil longer. The two organisms cannot be used concurrently, as Milky Spore needs a live host, “Although,” Mike remarks, “They won’t be alive for long.” Mike recommends that if you have a major beetle problem in your lawn, you should use Milky Spore, but if you only have a small beetle problem, or if you’ve been using Milky Spore and it hasn’t been effective, then go ahead and try BTG and see how it works for you.

    A Bad Case of Voles

    Judy in Wilmington, DE has a bad case of voles! She’s always had them, but they have been much more plentiful this year. Mike clarifies that there are two similarly named and problematic underground creatures: Moles live completely underground, make raised tunnels, and don’t eat any plant matter. Voles, on the other hand, are little, mousey, shrew-like creatures that live half-underground, half-aboveground, make little runs in the ground, and eat lots of plant matter, especially spring bulbs. Now, since Judy says that she hasn’t noticed anything eating her plants, aside from the evil squirrels who’ve been taking little bites out of her tomatoes, and to which Mike prescribes the solution of a motion-sensing sprinkler, Mike is tempted not to do anything to these little furry guys. However, if they do become a problem, Mike recommends three possible solutions, the first one being mouse traps, baited with peanut butter, which Judy has already tried, and which the voles were able to defeat. The next is a castor oil solution, which will impart a scent to the soil which we can’t smell, but the moles and voles hate. He also recommends electric mouse traps, which will zap any little critters that go into the holes in the trap to explore. When it’s gone off, the light will come on, to tell you to empty the traps. “We can’t solve the world’s problems, but we can certainly take care of your voles!”

    Fall Leaves for Compost

    Andy from Pitman, NJ saves leaves from the fall to compost them. He had previously been burying them in the garden and he wants to know if there are any commercially available leaf shredders that can handle wet, matted leaves. Mike comments that it’s never a good idea to bury carbonaceous material in the garden: it’ll tie up soil nutrients and nitrogen, stunting your plants’ growth. “Nature don’t go burying nothin.” Shred the leaves as they come down to help them break down quickly, because if you don’t do that, that can create an impermeable surface and also starve your plants. Instead, get an electric leaf blower with a reverse setting and a bag to put on your shoulder. Suck the leaves up as you stand, they go into an impeller built into the machine, it gets collected in your bag, and then put that in your compost pile, or put it down as mulch. Just put down a 2-inch layer of leaves on the surface, and it’ll keep weeds down and bring worms in. As far as wet leaves go, you can just pile them up and let them compost, or spread them out to dry, then borrow a riding lawnmower with a bagging attachment and collect those leaves up, because you never want to suck up those wet leaves with your leaf blower.

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