Question
What causes this yellowing in my yard?  I am using the Organica 4 Step program for my yard.  I just applied Lawn Booster to my yard last week.  Should I add anything else to my lawn or will it be okay.  Also, I aerated and overseeded the lawn a few weeks ago to help strengthen the lawn in the spring.

Answer
Sounds like you really love your Lawn -- Organica makes a top drawer first rate product.  You didn't mention your location, so I'm going to guess here that you may be living in one of the cooler U.S. regions.  Either the weather has been cool and damp, or your Grass Seed was watered diligently to facilitate germination.  Either of those sound like a possibility?

Aerating has traditionally been used to get air into Soil underfoot where that you want Grass roots to grow.  But there's a down side to Aerating: It breaks up beneficial Fungi and destroys their network, turning back the clock to brand new Fungi that start all over again (until you aerate again).  Earthworms aren't too crazy about aeration, either.

So when does aerating makes sense?

Gardening author Jeff Lowenfels recommends plug-aerating a Lawn that has not had the opportunity to develop a healthy soil food web.  The Lawn may be newly Seeded or Sodded on top of rototilled Soil.  Or it may have been chemically treated recently with chemical fertilizers or other products.  Or it may even be a Soil that doesn't drain effectively -- lack of Oxygen kills aerobic microbes and insects.  All these are missing a network of healthy, disease-fighting Fungi and other microorganisms.  Plug aerating will do more good than harm.  Writes Lowenfels, these Lawns 'should be plug-aerated, a procedure wherein 2-inch-long plugs of Soil are pulled from the Lawn, creating holes thorughout.  These holes open up the Lawn, allowing water, air and organic food to enter the root zone.  The plugs should be left on the Lawn and allowed to decay.  Plug aeration in the early Spring every 3 or 4 years will help the Soil food web because it helps repair compaction caused by the weight of snow and ice or the back and forths of pets, children, and vehicles.'  [See 'Teaming with Microbes' by Lowenfels and Wayne Lewis]

As I said, I am only guessing -- if you would perhaps confirm or correct me, we can talk about it further.  The pattern of these yellow patches or areas will also be helpful.

THE LONG ISLAND GARDENER