Can anyone explain what just happen? Yes sir, I said it. So after discovering my soil was heavily compacted, I should have took hint when the Spring rains came and the water stood in water even though I aerated earlier in the year. Our soil is very, very poor and needs major work. When we moved in, I'm sure some of you have seen the pictures, our soil was hard as a brick, with literally bricks under the soil. Nothing, but crab-grass, not a strand or blade of grass in sight. So it seems the summer, heat, and months of no rain, 45% less rain-fall then previous years dried our soil out and compacted it again, or was it me playing with the new walk behinds that compacted it? Anyway, after core aerating today (3 passes) I noticed the change of color in the lawn went from dark green to more of a lime green color. I thought my eyes were playing tricks. When my wife got ready to leave, she noticed the same thing and said something without me even mentioning it. Does anyone know what reaction would cause the lawn to go from dark green to light green after an aeration?