What's your economic threshold on weeds? It should be zero, maintains Brian Freed.

“You can’t stand weeds with no-till because the weed seed populations will build up on you,” says the president of AgFocus, a Lexington, Ill., based crop consulting firm.

Freed provides crop consulting services to farmers throughout the Midwest, which includes helping them solve their toughest weed problems.

Hemp Dogbane, Milkweed

To control hemp dogbane and milkweed in no-tilled Roundup Ready soybeans, he recommends spraying Roundup only after the bud or flower stage. Since plant sugars don’t start moving down from the top of the plant to the roots until you hit bud stage, you need to kill the roots in these weeds, he says.

A problem with applying a burndown herbicide early is that while the herbicide does a good job, it tends to set plants back. The result is that when you want to control other weeds in season, some are no longer at the bud or flower stage.

“I like to have a good flower on the growing plants when spraying,” he says. “You have to adjust weed control programs to do that accordingly. Since you can’t have other annuals that force you to spray earlier, you need other programs to control those weeds and not choke out your crop.”

Another critical point when applying Roundup is the amount of spray coverage. A lot of no-tillers apply 10 to 12 gallons of water. While you can run those volumes in some areas, you may want…