First of all, I can't even imagine how expensive a project that will be! You're using horticultural/food grade diatomaceous earth (as opposed to pool filter stuff)?

Secondly, as far as I am concerned, there IS no good time to broadcast diatomaceous earth (DE) on your lawn. DE is a broad spectrum control agent that is capable of doing more harm than good and for a long time. There are many very beneficial creatures, including some natural predators of your ticks that can be harmed by the DE. Its best uses are very directed and contained, not broadcast over a large area.

Lastly, you will need to protect your lungs and your eyes if you decide to broadcast DE.

I'll be using food grade DE and it's not that expensive. I've looked at chemical treatments which seem worse by comparison on their impact. What else can be used instead to get rid of ticks? From what I've read, DE seems like a good choice and I may elect to do perimeter treatment and areas closest to the house.

Thanks!