1. Pre-emergent herbicides block weed seeds from germinating. They will not kill weeds already up. Use the fertilizer schedule to have a healthier yard, ultimately the best defense against weeds. Period.)
2. Once a weed is up, you need a post-emergent herbicide. For example, a broadleaf weed control for clover.
3. There are different forms of post-emergent herbicides. Some are “selective,” and some are “non-selective.” Glyphosate herbicides (Roundup, Eraser and organic vinegar solutions) are non-selective — they kill every kind of weed or grass. Selective herbicides usually target a specific category of weeds – broadleaf, grassy or sedge.
4. If you’re late with the application of pre-emergent herbicides, you can still do it. You just may not get total control, as some weeds may have already germinated.
5. Observe any temperature restrictions of selective herbicides. For example, we now have cool-season herbicides for broadleaf weed control. We didn’t have that 30 years ago. And we don’t used products like Image when it’s too hot.
6. The powdered organic Garden Weasel AG Crabgrass product from Agra Lawn was originally designed for grassy weeds, although it can control a few broadleaf weeds I have had personal success with it on Virginia buttonweed.
7. Nutgrass and nutsedge are neither grassy nor broadleaf weeds. I recommend sedge controls for those.
8. The granular version of Bonide Weed Beater Complete is a real one-of-a-kind product — a pre- and post-emergent herbicide in one bag. The “pre” is essentially Barricade, which blocks broadleaf and grassy weed seed germination. But the “post” only works on broadleaf weeds.
9. Surfactants are neither applicable nor necessary for granular pre- or post-emergent herbicides.
10. Surfactants should be added to pretty much every liquid herbicide so the treatment actually sticks to the weeds.