Crabgrass Rescue: How to Kill It Without Spending a Fortune
You’re standing in your yard staring at clumps of light-green, wide-bladed grass fanning out toward the driveway. The bags of “crabgrass preventer” at Home Depot are already marked down. Their job ended in March. You’re in rescue territory now.
The prodiamine you buy for this is the same molecule as the pricey big-box bag. See Same Chemical, Different Price.
Here’s what makes crabgrass worse than most weed problems: a single plant drops 150,000+ seeds before it dies in the fall. A few plants this year become hundreds next year. Every week you wait, the plants get bigger, harder to kill, and closer to setting seed. That “weed and feed” bag on the endcap at Lowe’s, the one with weeds on the label, is almost entirely fertilizer plus a broadleaf herbicide. It does not kill crabgrass. Crabgrass is a grass, not a broadleaf.
The right tool is a specific active ingredient that most homeowners have never heard of. It costs under $30 to rescue most lawns. But your grass type changes everything, one common Southern grass means the standard rescue product will destroy your lawn rather than save it.
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The short shopping list: Generic liquid quinclorac, 64 oz (~$59.99) · MSO surfactant. The surfactant is part of the application, not an upgrade. All picks and why.
What Crabgrass Actually Is
Crabgrass (Digitaria sanguinalis and Digitaria ischaemum) is an annual. It germinates when soil temperatures hit roughly 55°F in spring, grows aggressively all summer, drops its seed load in late summer, and dies at the first hard frost. The seeds sit in your soil and repeat the cycle next spring.
That annual cycle is why prevention is so much cheaper than rescue. One prodiamine application in late winter, $5 to $10 in chemical, blocks most of the year’s germination before it starts. One missed window means a post-emergent rescue program that costs 3 to 6 times as much. The math for next spring is obvious. This article handles the problem you already have.
How to Be Sure It’s Crabgrass
Before buying anything, confirm you’re looking at crabgrass and not a look-alike.
Crabgrass: Grows in a low, flat, star-shaped clump from a central crown. Like fingers spreading outward from a hand laid flat on the ground. Light to yellow-green color, distinctly lighter than most lawn grasses. Wide blades (1/4 to 1/2 inch), slightly hairy on large crabgrass. Loves edges along driveways and sidewalks where soil heats fastest.
Goosegrass: Similar sprawling shape but the base is white or silvery. Stems bunch tightly at the crown, like a wagon-wheel hub. Quinclorac does not control goosegrass. If that’s what you have, you need a different product.
Dallisgrass: Coarser, taller, perennial. Comes back from the same crown every year. Quinclorac doesn’t reliably kill it either.
Bermudagrass invading a cool-season lawn: Fine-textured, wiry stems, spreads aggressively. A completely different problem that needs a different product.
If you’re not sure, snap a photo of the plant base and the overall growth pattern and post it in any major lawn forum before spending money. Misidentification is the most expensive mistake in weed control.
Critical Warning: Centipede and St. Augustine Owners
If your lawn is centipedegrass or St. Augustinegrass, do not apply quinclorac. It will damage or kill your lawn.
Quinclorac is safe on bermuda, zoysia, tall fescue, Kentucky bluegrass, perennial ryegrass, and bahia. It is not safe on centipede or St. Augustine, two of the most common lawn grasses in the Lower South. This isn’t a fine-print caution. It’s the difference between solving your crabgrass problem and destroying your lawn while trying.
If you’re not sure what grass you have: centipede is coarse, light-green, slow-growing, with a “peppered” texture. St. Augustine has wide, blunt-tipped blades and spreads by thick above-ground runners. Both are common in coastal and Deep South lawns.
Centipede and St. Augustine owners have fewer options. The honest answer for a heavy infestation is often to accept some crabgrass this year and invest in prevention for next spring. The options that do exist are in Crabgrass in St. Augustine and Centipede. Everything below is for bermuda, zoysia, bahia, tall fescue, Kentucky bluegrass and perennial ryegrass.
The Active Ingredient: Quinclorac
Quinclorac is the rescue product. It’s a synthetic auxin herbicide. It kills crabgrass at every growth stage, from small seedlings to mature multi-tiller mats, while leaving bermuda, zoysia, bahia, tall fescue, Kentucky bluegrass and perennial ryegrass unharmed at label rates. It’s the active ingredient in Drive XLR8 (the BASF branded original) and in generics sold as Quinclorac 75 DF and liquid quinclorac concentrates. The generic versions cost less than the brand name and contain the same active ingredient.
Quinclorac does not control goosegrass (the white-based, tightly bunched look-alike) or dallisgrass (the coarser, perennial one). If you’re not positive you have crabgrass, go back to the ID section above first.
A Surfactant Is Not Optional
This is the most common reason quinclorac applications fail: the homeowner sprays it without a surfactant, sees no results in a week, and concludes the product doesn’t work.
A surfactant is a spray additive that helps the herbicide penetrate the waxy crabgrass leaf surface. The specific type quinclorac labels call for is methylated seed oil (MSO). Without it, quinclorac delivers at roughly half its rated efficacy. The Drive XLR8 label and every extension publication on quinclorac say the same thing: the surfactant is part of the application, not an optional upgrade. A quart of generic MSO surfactant runs $15 to $20 and lasts a full season or more. Add it every time.
Rate: roughly 0.55 fl oz of surfactant per 1,000 sq ft, or per the quinclorac product label.
Timing: Earlier and Smaller Is Cheaper
Quinclorac works at every stage, but the kill is faster and cleaner on small plants. A crabgrass plant with 1 to 3 tillers (roughly the size of a quarter to a half dollar) will show reddening and twisting within 7 to 10 days and fully collapse within 2 to 3 weeks. A large multi-tiller mat from July or August will die, but it takes longer. Expect 3 to 4 weeks for full collapse, and a second application 3 weeks after the first may be needed.
Do not spray and then re-spray a week later because nothing looks different. That’s a wasted second application. Wait the full 3 weeks. Quinclorac is slow by design.
Air temperature: Quinclorac performs best between 70°F and 85°F. It slows down in cool weather and can stress warm-season turf when applied in extreme heat (95°F+). Cool-season lawns have a lower ceiling, covered in the next section. For summer applications, spray early morning before 10 a.m., when air temperatures are still in a comfortable range and the turf isn’t heat stressed.
Rain: No rain for at least 4 to 6 hours after application. Rain washes off undelivered chemistry.
Mowing: Don’t mow for at least 24 hours before or after spraying. The plant needs leaf surface to absorb the herbicide.
Fescue, Bluegrass and Rye: Two Things Change
The chemistry and the surfactant are the same on cool-season lawns. Two things are different: how hot it can be when you spray, and what quinclorac does to seed you put down afterward.
Spray cooler: under 85°F, ideally under 80°F
For warm-season grasses, the quinclorac temperature caution is mostly about slowing efficacy in cool weather. For fescue, bluegrass, and ryegrass, the concern runs the other direction: applying herbicides to turf that’s already heat-stressed can cause visible injury, yellowing, thinning, and slow recovery in mid-summer.
Fescue in particular enters semi-dormancy under sustained heat. Spraying a herbicide on semi-dormant, heat-stressed fescue adds insult to injury.
The rule: spray quinclorac on cool-season lawns in the early morning, before temperatures climb above 85°F. Ideally under 80°F. In most of the country, that window is reliable in late spring (May through early June) and again in early fall. Mid-July and August, when crabgrass is largest and most conspicuous, are also the worst times to spray a stressed fescue lawn. If you have to treat then, go early in the morning and don’t mow for 48 hours after.
The broader lesson: earlier is better, every time. Catching crabgrass at 1 to 3 tillers in May, when the plants are small and the fescue is still reasonably healthy, is a much cleaner situation than chasing mature mats in August when both the timing and the turf condition are working against you.
The fall overseeding conflict
This is the constraint that catches cool-season homeowners off guard every year.
Quinclorac has a reseed restriction of approximately 30 days after application before cool-season grass seed can be planted into treated turf. Spray for crabgrass in late August or September and then immediately overseed fescue, and the quinclorac in the soil will suppress the new seed. You’ll get patchy germination or none at all in the treated areas.
Here’s how to manage it:
If you treat crabgrass in late May or June, the 30-day restriction clears well before fall overseeding in September or October. No conflict.
If you’re treating crabgrass in late summer, August or September, you need to choose. Treat the crabgrass now, wait the full 30 days, and overseed late. Or overseed on schedule and skip the post-emergent this year, accepting the crabgrass for this season and investing in pre-emergent for next spring.
For most cool-season homeowners, the pre-emergent program next February is the better investment. Prodiamine at soil-temp-trigger timing prevents 80 to 90% of the year’s crabgrass germination before it starts, at a fraction of what rescue chemistry costs.
Product Picks: 3 Tiers
All three tiers use the same chemistry at the same effective rate. The difference is formulation, brand, and how much measuring you want to do.
Tier 1, Cheapest per application (~$15–25 per application on 5,000 sq ft)
Generic Quinclorac 75 DF + MSO surfactant
Quinclorac 75 DF is the dry flowable version, a wettable powder you dissolve in water in a tank sprayer. A 1 lb bottle runs about $80 up front, but the application rate is roughly 0.37 oz per 1,000 sq ft. That made it a multi-year supply for most home lawns. You need a scale that reads to the tenth of a gram or a measuring spoon.
Heads up: the 75 DF powder has been discontinued, so the link above goes to the generic liquid instead: Primesource Quinclorac 1.5L Select, 64 oz, $59.99 on Amazon (checked Oct 21, 2026). Same active ingredient, and at that price it works out a little cheaper per application than the powder did.
Total chemical cost per 5,000 sq ft application (quinclorac + surfactant): approximately $15 to $25.
Tier 2, Middle (~$15–30 per application on 5,000 sq ft)
Generic liquid quinclorac 18.92% + MSO surfactant
The liquid formulation of the same chemistry. About $47 for a 32 oz bottle, and easier to measure, just fl oz marks, no scale needed. The rate is 0.5 to 1.45 fl oz per 1,000 sq ft (use the higher rate for denser infestations or larger plants). A bottle gives you 20 to 50 applications depending on rate, and the per-application cost is essentially the same as Tier 1.
This is the right choice for most homeowners. The liquid mixes easier and there’s less margin for measuring error than the dry flowable.
Total chemical cost per 5,000 sq ft application: approximately $15 to $30.
Tier 3, Done-for-You (~$35–60 per application on 5,000 sq ft)
Q4 Plus combo concentrate (at DoMyOwn)
Q4 Plus by PBI-Gordon combines quinclorac (crabgrass) with 2,4-D and dicamba (broadleaf weeds like dandelion and clover) and sulfentrazone (yellow nutsedge, fast burn contact). One jug covers crabgrass, broadleaves, and sedge in a single pass.
A surfactant is still required for the quinclorac component to perform.
Rate is 1.5 to 2.2 fl oz per 1,000 sq ft. Higher cost per application than Tiers 1 and 2, but you’re paying for the combination. One application handles the mixed weed problem most lawns actually have in early summer. If you only have crabgrass, Tier 1 or Tier 2 wins on price.
The Actual Program
On my own zoysia in Georgia zone 8a, crabgrass is a manageable annual problem because split-rate prodiamine prevents about 90% of it before anything emerges. Here’s the full program. Unless you have a good reason to run it differently, this is what I do:
October or November: Prodiamine 65 WDG at 0.37 oz per 1,000 sq ft. The fall application does double duty: it puts down the barrier that catches poa annua and the winter annuals germinating in fall, and its residual carries into the new year. Chemical cost on 8,000 sq ft: about $5.
Late February or early March: Second prodiamine application at the same rate. This is the one that shuts the door on the year’s crabgrass germination before soil temps hit 55°F, and it extends coverage through the spring and early summer window. Another $5.
May or June, only if escapes appear: Quinclorac + surfactant, spot sprayed on the visible plants only, not broadcast across the lawn. For a typical year, that’s 10 to 20 individual plants treated with a 1-gallon hand sprayer.
The whole annual program runs $10 to $15 in chemical for 8,000 sq ft. The reason it stays cheap is that the pre-emergent does almost all the work, and the fall app means the lawn is never unprotected. Quinclorac is the backup for the small percentage that escapes the barrier.
For anyone reading this in late May looking at a lawn full of crabgrass: the rescue cost is higher, typically $30 to $60 for a full application on 8,000 sq ft, but that’s still less than one visit from a lawn service. The lesson at the end of it is the same. Put down prodiamine this fall and again in late winter, and you won’t need this article again.
3 Anti-Patterns
No surfactant. If you’ve already sprayed quinclorac without a surfactant and it didn’t seem to work, that’s almost certainly why. Re-spray with the surfactant this time. Don’t skip the adjuvant to save $15.
Wrong timing or wrong expectations. Spraying mature crabgrass in August and expecting it gone in a week is a setup for failure. Large plants take 3 to 4 weeks to fully collapse. The seeds are also close to set by mid-August, so even a successful kill doesn’t help next year the way an early-summer application would. Spray early and give the chemistry time to work.
Wrong identification. Goosegrass looks like crabgrass and quinclorac does not control it. If your spray didn’t work at all, no reddening, no twisting, nothing, go back and check the weed ID before re-spraying. Same product, same result.
Want this sorted for your own lawn? The 7-question lawn plan matches your grass, your problems and how much effort you want to put in, then hands you the shopping list.
Quick Reference
| Item | Detail |
|---|---|
| What is it? | Annual grass weed, germinates at 55°F soil temp |
| Standard rescue product | Quinclorac (Drive XLR8 or generic) |
| NOT safe on | Centipede, St. Augustine |
| Surfactant required? | Yes, MSO type, every application |
| Seeds per plant | 150,000+, catch it early |
| Cool-season lawns | Spray below 85°F; wait about 30 days before overseeding |
| Best long-term fix | Pre-emergent (prodiamine) next late winter |
Products Mentioned in This Article
- BASF Drive XLR8 (quinclorac, branded), 64 oz, ~$70, DoMyOwn · also on Amazon
- Generic liquid quinclorac (Primesource 1.5L Select), 64 oz, ~$60, Amazon. Same active ingredient as Drive XLR8, and as of October 2026 it’s the cheaper jug. The 75 DF powder is discontinued.
- MSO surfactant, 32 oz, ~$20, Amazon
- Quali-Pro Prodiamine 65 WDG, 5 lb, ~$80, years of pre-emergent, Amazon · also on Amazon
- Q4 Plus (quinclorac + 2,4-D + dicamba + sulfentrazone), ~$50–65, DoMyOwn
For timing mistakes that cost more than just the chemical, see Patience: When the Best Lawn Care Move Is No Move at All.
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