Faust has grass allergies (among his many)... definitely, definitely stay away from any pesticides and fertilizers.
Last summer I had a guy mow my yard who - unbeknownst to me - sprayed pesticides along my fence and the next day Faust was one big "walking sore".
Even now he has some break-outs as soon as my grass is freshly mowed, and then it tapers of for a couple of weeks, until next time. I give Benadryl as needed, but if I'm not right on top of it each time he develops those dreaded and nasty secondary skin infections from scratching so much.
He is also the one who LOVES to roll around, and sunbathe, on a freshly mowed lawn, so I'm forever yelling at him to "get up" and "stop it"...

I can see a huge difference as soon as it gets cooler - we had almost no problems during the fall and winter of last year (as long as he also stayed on a strict low-allergen kibble)... but as soon as it got warmer and the grass started to grow - voila.
I do try to limit his exposure, but it's hard when you have a huge yard and all the other dogs enjoy being outside.
Allergies in any form SUCK, but environmental ones are the WORST, IMO.
I'm thinking of bubble-wrapping him next year, from about April 'til October, and he'll just have to spend the whole summer sitting on a shelf in the living room.
