Perhaps the label is too conservative. I planted Pennington Smart Seed (high in perennial rye) in potting soil in a shallow baking pan. After 7 days outside, the tallest sprouts were about 1-inch tall. On day 7, I treated with Dimension (dithiopyr) crabgrass control on fertilizer (19-0-6). The pan was 7 by 10 inches. I treated with a gram of the fertilizer/Dimension granules, owing to lack of equipment for measuring amounts less than a gram. This came out to about 4.5 pounds per 1000 sqft. (About .2 lbs per acre of active dithiopyr ingredient per acre). So far at 24 hours there has been no injury to the new grass. More results later.