I have developed an almost completely organic program for my customers(except for spot weed control), and because customers want a quick green up in the spring I'm thinking of doing the first app synthetic. Maybe even with a synthetic pre-em? Is this going to have a huge adverse effect on the health of the soil and the microbes? If I use an organic with microbes for the 2nd application should that take care of it? Any advice you guys have would be great. I of course just want to have happy customers with beautiful lawns and healthy soil. Thanks for your help. You guys rock!