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Weed and feed this spring with corn gluten

Friday - 3/22/2013, 10:40am  ET

daffodils (Dan Kitwood/Getty Images News/Getty Images)
All spring bulbs contain a natural antifreeze that makes them invulnerable to cold weather. (Dan Kitwood/Getty Images)

Technological breakthrough: Liquified, organic corn gluten meal

WTOP Garden Editor Mike McGrath


Mike McGrath,

Editor's Note: Mike will appear on Saturday and Sunday April 6 and 7 at the Delaware Home and Garden Show at the Sheraton Dover Hotel. Visit for more information.

Weed-preventing corn gluten now in liquid form

Sekar in Herndon writes: "I am a great fan of the organic weed preventer Corn Gluten Meal, and have been using it on our lawn for the past five years. As I was about to purchase this year's supply, I came across a product at Home Depot that seems to be a liquefied form of corn gluten. What is your opinion of this spray? Or should I stick with granulated corn gluten?"

I would definitely try the spray, Sekar! The same Iowa State researchers who developed the granular form of corn gluten meal as an all-natural weed and feed have been working on a liquid formulation for years. And I didn't realize it was finally on the market. I just checked with them, and they confirmed that it is the real deal — a licensed variation of their original granulated formation. And this is the first year it's commercially available!

If anything, the liquid form should be even better at preventing the germination of crabgrass and other weed seeds as it goes down wet, which should really jump- start the process of killing crabgrass and other dormant weed seeds.

Lawns do better with the two-step dance

Charles in Fredericksburg writes: "I've always used typical lawn care products from Scott's and want to change to organic. Do you have a schedule as to when various products should be applied?"

Good for you, Charles! And yes.

Step One: You should be prepared to spread corn gluten meal - the all-natural pre- emergent weed and feed - on your lawn soon. It'll prevent crabgrass and other dormant weed seeds from germinating and provide a gentle spring feeding.

Then start the season with a new or newly-sharpened blade, cut your lawn at three inches high and never bag the clippings. Those clippings are 10 percent nitrogen (the primary lawn food), and returning them to the turf provides your lawn with a gentle natural feeding every time you mow. Do not apply any other form of food to your lawn during the summer.

Step Two: Feed your lawn again in the fall. That's late August if you use more corn gluten (to prevent late-season weeds like dandelion and clover); or in September with a bagged organic lawn fertilizer. Or rake an inch of compost into the turf. Our grasses crave the organic matter that compost provides.

And that's it! Lawns don't need four steps. They look their best when they do the two-step.

Where can we find this magical meal of the gluten of corn?

Yvonne in Havertown, Gene in Fredericksburg and a legion of other listeners all ask: Where can we find the corn gluten meal you say we should use on our lawns this spring?

It's a question as reliably perennial as the daffodils brightening up landscapes this time of year.

You'll generally find the biggest selection of corn gluten products at large independent garden centers. The brand names most frequently found at retailers include Espoma (the makers of Holly-Tone), Concern and Bradfield. (All have store finders at their websites, helping identify the sources closest to you).

But don't delay. To prevent crabgrass and other weed seeds, you need to apply corn gluten right before the soil temperature reaches 55 degrees. And the soil is already up to 45 degrees in Prince George's County, so I'm guesstimating that the first week of April is going to be ideal.

Corn gluten timing; a new resource

"I can go your Chesapeake Bay water temperature link one better," brags Burt in Rockville. "Here's a link to the USDA National Resources Conservation Services monitoring station in Powder Mill, Md., (Prince George's County) where you can see daily soil temperatures as measured 2 inches, 4 inches and 8 inches below the surface.

It says that the soil temperature today is 44 degrees at 4 inches down. That indeed is very close to the Chesapeake Bay water temperature you've urged listeners to follow!"

Thank you, Burt. We have the best listeners here at WTOP. Now, this site is a little tough to navigate, so here's what you do:

  • Open the page.
  • Choose "soil moisture and temperature" from the first column.
  • Go over to the fourth column (the yellow one), choose 'last 7 days' and then click 'view current' right above that. You'll be taken to the page with the readings.
  • Today's date will be the last one on the list, and the column that says "STO.I-1:-4 (degC)" (fourth from the right) has the soil temperature we're looking for.
  • But, it's in Celsius. Go here to convert it to Fahrenheit. (Or do the math. Multiply the Celsius number by 1.8 and then add 32.)
  • Start spreading your corn gluten when the soil temperature number hits 50 degrees, so the material will be down and active by the time the soil reaches the crabgrass germination temperature of 55 degrees (or 12.7 degrees Celsius, for all you metric fans out there)
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