Lawn care
How to get rid of crabgrass in your lawn
The secret to a crabgrass-free lawn is timing, stop it before it sprouts, and clean up what slips through.
Crabgrass is the weed that makes an otherwise nice lawn look ragged. It shows up in mid-to-late spring, spreads fast in thin or sunny spots, and its coarse, light-green blades stand out against your turf. Here’s the thing most people get wrong: by the time you can see crabgrass, it’s already too late to prevent it for that year. Beating crabgrass is almost entirely about timing, and once you understand the two-part approach, it’s genuinely manageable.
Why crabgrass is so hard to beat
Crabgrass is an annual weed, it grows from seed each year, sets thousands of new seeds, and dies off in fall, leaving those seeds waiting in the soil for next spring. That means the battle isn’t really with the plant you see; it’s with the seeds germinating below the surface. Pulling mature crabgrass barely helps, because the seeds are already down for next year. The only reliable way to win is to stop the seeds from establishing in the first place, and then deal with any stragglers while they’re young.
The two-part approach
Step 1 · Prevent it
Pendi Hydrocap
A pre-emergent herbicide (38.7% Pendimethalin) that creates a barrier in the soil, stopping crabgrass and 40+ other weeds before they can establish. Its water-based, encapsulated formula means low staining and low odor, a real plus around driveways and walkways. Works on both cool-season and warm-season lawns.
Apply BEFORE crabgrass sprouts · water in after applying
Step 2 · Clean up escapes
QuinKill Max
A post-emergent herbicide (Quinclorac) that kills crabgrass that already came up, without harming labeled lawn grasses. Best on young, actively growing crabgrass. Treated weeds curl and die back over several days.
1.45 fl. oz. per 1,000 sq. ft. · do NOT water in for 24 hours
Timing is everything: apply the pre-emergent early
The single biggest factor in crabgrass control is getting your pre-emergent down before the seeds germinate. Crabgrass starts sprouting once soil temperatures reach the mid-50s°F for a few days in a row, usually early spring, but the exact timing shifts year to year and depends on where you live. A common homeowner trick is to apply around the time forsythia shrubs finish blooming, which lines up well with soil warming in many regions. Miss that window by a couple of weeks and the barrier goes down after the crabgrass is already up, when it can no longer prevent it. After applying Pendi Hydrocap, water it in with about half an inch of irrigation or rainfall to activate the barrier.
Clean up what slips through
Even a well-timed pre-emergent occasionally misses a few spots, thin areas, edges, or places where the barrier got disturbed. That’s what QuinKill Max is for. Spot-treat young crabgrass while it’s still small and actively growing, since mature crabgrass is much harder to kill. Apply at 1.45 fluid ounces per 1,000 square feet. One key difference from the pre-emergent: unlike Pendi Hydrocap, QuinKill Max should NOT be watered in, the label says do not water or irrigate for 24 hours after applying. And don’t mow for two days before or after treating, to give the herbicide time to work.
Important: check your grass type first
QuinKill Max is labeled for lawns like tall fescue, bermuda, zoysia, Kentucky bluegrass, and perennial ryegrass, but it must NOT be used on St. Augustinegrass, centipedegrass, Bahiagrass, carpetgrass, dichondra, or lawns where desirable clover is present, it can damage those. If you’re not sure what type of grass you have, confirm before spraying. Pendi Hydrocap, by contrast, can be used on both cool- and warm-season lawns. Also avoid getting QuinKill Max on tomatoes, peppers, eggplants, or other garden plants, and don’t plant tomatoes or carrots in a treated area for up to two years afterward.
A simple seasonal plan
Early spring: apply Pendi Hydrocap before soil hits the mid-50s°F (around when forsythia finishes blooming), then water it in
Late spring / summer: spot-treat any crabgrass that broke through with QuinKill Max while it’s young (and don’t water it in for 24 hours)
All season: mow at the right height and keep your lawn thick, dense turf is the best crabgrass defense there is
Next spring: repeat the pre-emergent, crabgrass control is a yearly habit, not a one-time fix
Common questions
When should I put down crabgrass preventer?
Before the crabgrass seeds germinate, which is when soil temperatures reach the mid-50s°F for several days in a row, typically early spring. A handy visual cue is to apply around the time forsythia shrubs finish blooming. Applying after crabgrass has already sprouted means the pre-emergent can no longer prevent it.
Can I use these products on any type of grass?
Pendi Hydrocap can be used on both cool-season and warm-season lawns. QuinKill Max is labeled for grasses like tall fescue, bermuda, zoysia, Kentucky bluegrass, and perennial ryegrass, but must not be used on St. Augustinegrass, centipedegrass, Bahiagrass, carpetgrass, dichondra, or lawns with desirable clover. Always confirm your grass type against the label before applying.
Should I water in QuinKill Max after applying?
No. Unlike a pre-emergent, QuinKill Max should not be watered in, the label says do not water or irrigate for 24 hours after application. Pendi Hydrocap is the opposite: it needs about half an inch of water after applying to activate the soil barrier. It’s an easy pair to mix up, so keep them straight.
Will a pre-emergent kill crabgrass that’s already growing?
No. A pre-emergent like Pendi Hydrocap stops seeds from establishing, but it won’t kill crabgrass that has already emerged. For crabgrass that’s already up, use a post-emergent like QuinKill Max on the young plants instead.
Why does crabgrass keep coming back every year?
Because it drops thousands of seeds each season that wait in the soil for next spring. That’s why crabgrass control is an annual routine, applying a pre-emergent each spring stops that new crop of seeds before it can establish.
Is one application enough for the whole season?
A single well-timed pre-emergent covers much of the season. Follow the label for timing and maximum rates, QuinKill Max, for example, has an annual per-acre limit, so don’t exceed the labeled amount across the year.
Ready for a crabgrass-free lawn?
Contact Agrisel to find a reseller carrying Pendi Hydrocap and QuinKill Max for your lawn.