On 7/5/17 8:39 PM, Vic Smith wrote:
On Wed, 5 Jul 2017 17:18:14 -0700 (PDT), trader_4 wrote:
Also, you're dealing with cracks, where it will be somewhat harder for
weeds to get started than in an open area, so a month doesn't surprise me.
I have to spray cracks less frequently than open areas.
In places the cracks are 3-4 inches wide. I just went to the store and took a close look
on the way to the car. There are a few places that show green if you look close.
But most of the cracks are full of dead weed material and some dead pine needles.
It could need another application, but I don't remember doing it twice in a year.
Maybe by the time they get big enough to bother, they stop growing due to the season.
I just don't remember clearly.

The dead weeds and pine needle might be helping. No sunlight
on the actual dirt.
Corn and soybean plants eventually shade the soil. That helps keep
weeds from germinating.