Question
Hey
I live in Ashburn, Northern VA and have a big lawn mostly covered with grass. The lawn is now showing up with some weeds. When i moved in the house in summer, a landscape person suggested not to use any weed control as there was danger of it burning the grass due to high temperature. My question is the recommendation for FERTILIZER/WEED CONTROL to use and WHEN to prevent/kill weed while keeping lawn healthy? Also, generally speaking what are things we need to do to keep healthy lawn as we move progress through various seasons? Please advise.

Thanks,
Manish

Answer
Why do Lawns get Weeds?

There are a million reasons, Manish.  But NONE of them is 'Not Enough Weedkiller'.  Weeds do not overtake a Lawn because there is no Crabgrass Killer.

Manish, did you know that Lawn Grass and Weeds DO NOT LIKE THE SAME KIND OF SOIL?

Lots of Weeds LOVE Acid Soil.  They THRIVE in a low pH.

Cool Season Grass prefers Soil SLIGHTLY Acidic (not Alkaline).  True story.

Tilt the scale in the wrong direction and you build Weeds.

Which why we have Step 1:  Get your Soil tested.  Because if you do, you'll know EXACTLY what to do to get it straight.

I know, I know.  What about all those commercials?  Those ads?  What about all those very nice Lawns we've seen over the decades that had lots of Weedkiller?  It kills Weeds!  End of story.

Yes, my friend, Weedkiller kills Weeds.  But relentless application of megadoses of Weed N Feed and Weed B Gone has caused a lot of problems, too.

There's another reason to move on:  Science.  You wouldn't believe how much money goes into research about Grass and Gardening.  They learned about N-P-K a hundred years ago.  There have been thousands of discoveries about Soil chemistry and Grass botany since then, and HUNDREDS of discoveries in the past 10 years alone -- How plants and Trees and Grass all grow.  What makes them sick.  Why some plants can resist insect attack. Ways to use that information in other plants.  Where flower colors come from.  We've bloomed the first Blue Roses.  We've cloned Sheep.  We've broken the DNA code of Fungi.  Analyzed chemicals secreted by roots into the Soil to repel competing plants, and by certain leaves to repel insects.

We know an incredible amount of stuff that we didn't know even 20 years ago.  Doesn't it make sense to use this new information to grow Grass?

Tell me, Manish, did you feed your Lawn this Summer?  If you did, it was probably a high-Nitrogen Chemical fertilizer.  Nitrogen is actually one of your best weapons for whacking Weeds.

Yep, you read that right.  NITROGEN.

University of Illinois researchers fed Tall Fescue Grass different doses of Nitrogen, and published the results:

www.turf.uiuc.edu/research/summaries/1994/94_3.1.pdf#search='university%20test%20mowing%20height'

Their findings:

'Annual bluegrass populations [Translation: WEEDS] were greatest in Tall Fescue maintained at a 1 or 2 inch mowing height.' (Note this 'annual bluegrass' is a famous Weed, not that bluegreen Grass from Kentucky.)

Researchers also observed: 'Crabgrass populations INCREASED as mowing height DECREASED...'

See that?  Had nothing to do with Weedkiller.  It did not matter how much Nitrogen they used.  ANY Nitrogen was better than NONE when it came to making Weeds disappear.  Putting down ZERO fertilizer had the worst results: 'Tall Fescue that was not fertilized had significantly higher broadleaf Weed populations than turf fertilized with any Nitrogen.'

It just boils down to giving the Grass what it likes.  Especially when the Weeds dislike it even more.

By the way, the researchers in the study above also said: 'Even a low annual rate of Nitrogen fertilization can decrease broadleaf Weed populations and reduce or eliminate the need for Herbicide control.'

Let's read that again:

"...REDUCE OR ELIMINATE THE NEED FOR HERBICIDE..."

Music to my ears.

News flash: There are special Weedkiller cocktails on the market and in the pipeline that are based on chemicals made by certain plants to damage competing plants that get too close.  This concept first came up back in the 1930s, but scientists are still figuring out how common this is (very), what the chemicals are, and what they do.  Odds are you never studied this in school or even read about it in a Lawn article.  I told someone just the other day about new work with Maple leaves to make Organic products that target Weeds and not Grass.

Now, although I know you thought you wanted a quick, easy Weed wipeout and Scotts powder to get rid of the grassona non grata in your Lawn, here's one more point I want to make.

Pesticide companies are making a killing in this business.  They will not give up easily.  Scotts spends MILLIONS to sell its pesticides and herbicides and fungicides.  They have amazing commercials.

The Lawns look beautiful, the people look happy, the whole message is, Here is your American Dream.  And they target people just like you.  It's working.

And why not?

When people see the Scotts ads on TV during Superbowl Halftime, nothing ever goes wrong.  It doesn't even rain at those houses on TV.

The Corn Gluten Meal treatment is my favorite weed killer.  This stuff is applied in the spring -- I must have written about this 100 times in as many days -- to halt seeds as they germinate.  The scientific evidence is extensive.  Read this article if you have any doubts and you'll be convinced:

www.gluten.iastate.edu/pdf/nyt.pdf (The New York Times)

You would use this next Spring.

One of my favorite articles appeared in the Kansas State University Coop Extension, 'Horticulturist Gives Top Reasons Weeds Invade Kansas Lawns':

www.oznet.ksu.edu/News/sty/2000/weedsinvade.htm

Next:  Tell me, what grass are you growing, Manish?  Any idea?  Fescue, Tall or Short?  Rye?  Bluegrass?  Zoysia?

April and May are when cool Lawn Grasses do almost half their growing for the season.  If you mow them just right, you'll be making them stronger -- while weakening alien growth in your lawn, 'light green patches' included.

Purdue University's Cooperative Extension website posting, 'Lawn Care/Basics for Homeowners-Lawn Care/Mowing', explains why:

www.purdue.edu/dp/envirosoft/lawn/src/mowing2.htm#Height)

'Each turf species has a characteristic mowing height tolerance range.  Mowing at heights above this range result in poor quality turf and where scalping occurs below the desired mowing height range.'

Some very scientific data says you should mow your Kentucky Bluegrass, Perennial Ryegrass and Fine Fescue at 2 to 2 1/2 inches.  For Tall Fescue, mow 2 1/2 inches to 3 inches.

During Summer Drought and Heat spells, mow a half inch higher.

All this works better than Weedkiller.  Best of all, it builds the health of your Grass.  Healthy Grass fights Weeds.

Purdue points out that ALL Grass benefits from the taller recommended mowings.  Mowing high keeps the blade longer, which means more Photosynthesis, which means deep root growth and healthier, disease resistant, drought tolerant Grass.

Here's what I think is going to happen, Manish.

In years to come, this stuff will be totally illegal.  Just like cigarettes, the evidence will be in.  The lawyers will be suing.  And all that damage will be done.

And all those people who ran out and bought the Scotts 1-2-3 Superfund Sitebuilder program will be living with the consequences.

DON'T be tempted by the very expensive commercials the Scotts Company uses to lock up something like 85 percent of the lawn products business in this country.

Now, we both know there are lots of VERY NICE PEOPLE who will tell you things like, 'It's not so bad.' 'Just a little won't hurt.' 'It's safe, I use it all the time.'  Right.  They used to say the same thing about Cigarettes, DDT, Agent Orange, Asbestos, Mercury, PCBs and Nuclear Radiation.

The Earth is Round.  Want to know more?  Let me know.

THE LONG ISLAND GARDENER