On Sunday, June 19, 2016 at 1:34:24 PM UTC-4, Bert wrote:
Is there a commercial product that can be applied to lawns that
prevents seeds from germinating, as Preen claims it does for gardens?

I'm mainly interested in stopping the maple and ash tree seeds that
cover our lawn in the spring.

I've seen people suggest simply using Preen, but it's clearly labeled as
not being for use on lawns, and while I haven't done the math, I think
it would be rather expensive to do our entire front and back yards.

I really wouldn't care much about the ash sprouts if they would simply
match the color of the grass. The darker maple sprouts blend in pretty
well.

--
St. Paul, MN

A pre-emergent crabgrass product might work. It prevents germination of
most weeds, but it only lasts a month or so.