Q4 Plus Turf Herbicide
Q4 Plus is PBI-Gordon’s four-way herbicide for lawns with a mix of weeds. Quinclorac handles crabgrass, sulfentrazone adds sedge activity, and 2,4-D plus dicamba take out broadleaf weeds. It’s best when one spray needs to cover crabgrass and dandelions at the same time.
Active ingredients
Quinclorac 8.43%, sulfentrazone 0.69%, 2,4-D 11.81%, dicamba 1.49%
Best for
Mixed crabgrass and broadleaf weeds
Rate
2.6–3.0 fl oz per gal per 1,000 sq ft, cool-season (label)
Lawn types
Bluegrass, fescues, ryegrass, bermuda, zoysia
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Plate · Q4 Plus
Q4 Plus, a four-ingredient grassy and broadleaf weed killer.
What it’s for
Q4 Plus made the list in our crabgrass killer tests as the all-in-one option. It’s useful in summer when crabgrass, clover, dandelion and other broadleaf weeds are all showing at once. The quinclorac works best on young crabgrass, so spray early, before the weed tillers out.
The trade-off, per our roundup: it often takes more than one application to clean up crabgrass, and the use rate is high, so a jug goes quickly. For crabgrass alone, a straight quinclorac product such as Drive XLR8 goes further.
How to use it
On cool-season lawns, the label spot rate is 2.6 to 3.0 fl oz in a gallon of water per 1,000 sq ft. Warm-season turf takes less: 1.84 to 2.57 fl oz. Broadcast rates are listed per acre on the label.
Spray in the morning on actively growing weeds. Hold off watering for 24 hours, and don’t mow for 2 days before or after. Broadcast use is limited to 2 applications a year, at least 30 days apart.
Don’t broadcast above 90°F; spot sprays in heat can discolor turf. Not labeled for bentgrass, St. Augustine, centipede, bahia, carpetgrass, dichondra or lawns with clover you want to keep. Use caution on fine and tall fescue. Wait 4 weeks before reseeding, and keep people and pets off for 48 hours.
Read our full guides
Guide
The 5 best crabgrass killers
Q4 Plus against Drive XLR8, Acclaim Extra and Tenacity.
Guide
Getting rid of crabgrass in summer
What to spray once the preventer window has passed.
Ready to buy Q4 Plus?
Right for cool-season lawns with crabgrass and broadleaf weeds in the same spots.