A website you may want to check out is the following:
gardensalive.com

We like having a nice lawn but not at the expense of all the critters that set foot on our grass [our cats, neighbor's cats, squirrels, birds, etc. etc.].
My husband is fantical about weeds, pests, and keeping it green. Fortunately, this website/company only sells environmentally & critter safe products....and they DO work. We get our fertilizer, slug bait and other products from them. Other companies in your area may also sell non-chemical products as well.

In this day in age I think we should all be careful about how we impact the planet and the critters that inhabit our neighborhood and yards. We can be environmentally friendly by taking the time to look in the phone book or internet to find "safe" products.