The label is the law. Rates and restrictions below are taken from the product labels listed under Sources. Your product's own label governs; read it before you mix or apply. Mixing calculator · Disclaimer
- Active ingredient
- Pelargonic acid (nonanoic acid)
- Chemical class
- A fatty acid. The residential directions say it kills weeds and grasses by rapidly causing plant cells to lose water.[1]
- Mode of action
- Contact fatty acid herbicide that makes plant cells lose water; it is not named in the WSSA mechanism-of-action summary[1]
- Signal word
- Scythe Herbicide: Warning[1]
What a contact herbicide can't do
Scythe isn't carried through the plant, so it burns only what it coats. Mature, woody or perennial weeds are harder to control, and roots or rhizomes can send up new growth.[1]
It won't damage woody parts such as rose canes or tree trunks, but any green leaf it drifts onto can be killed. A shield helps when spraying beside plants you want to keep.[1]
Where it is used
Spray on a sunny day above 60 degrees for the fastest kill. Cool weather slows it down, and you should delay spraying if rain is expected within an hour.[1]
Wet every leaf evenly, but stop before the spray runs off. Shake or agitate the sprayer often, because the product separates quickly without mixing.[1]
Young weeds under 6 inches die fastest at the low rate. Use the higher rates for tall or dense weeds and for biennial or perennial weeds.[1]
You can replant as soon as the weeds are dead, since it leaves no soil activity. New seedlings and regrowth will need another spray.[1]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Scythe Herbicide[1] | Gowan Company, LLC | 10163-325 | 57.0% | emulsifiable concentrate | Warning |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Scythe Herbicide | Around ornamentals, trees, flowerbeds, sidewalks, fences, patios, driveways, home greenhouses and dormant turf | Annual weeds, mosses, perennial weed foliage, unwanted grasses | 4–13 fl oz product per gallon of water[1] Use 4 to 6.5 fl oz per gallon for annual weeds and mosses, 6.5 to 9 fl oz for perennial weeds, and 9 to 13 fl oz for edging or maximum burndown. One gallon of mix covers about 200 sq ft. |
Safety and environmental hazards
People
Signal word WARNING: causes substantial but temporary eye injury and skin irritation, and is harmful if inhaled or absorbed through the skin. Wear long sleeves, long pants, chemical-resistant gloves and goggles or safety glasses.[1]
Pets
Keep people, pets and livestock off treated areas until the spray has dried. Store the container somewhere dry that children and pets can't reach.[1]
Bees and pollinators
The Scythe label has no bee or pollinator statement. It burns only the green plant parts the spray touches.[1]
Fish and water
Don't apply it directly to water or where surface water is present, and don't contaminate water when rinsing equipment.[1]
Common questions
- How fast does pelargonic acid kill weeds?
- The residential label says you'll see results in minutes and dead weeds within hours: green tissue darkens, then browns and dies.[1]
- How much Scythe do I mix per gallon?
- 4 to 13 fl oz per gallon of water, depending on the weeds. The lowest rate handles annual weeds and moss, and the top rate is for edging.[1]
- Does Scythe stay in the soil?
- No. The label says it has no residual soil activity and won't move through soil to nearby plants, so it won't stop new weeds from sprouting.[1]
Sources
- U.S. EPA Pesticide Product Label System, “Scythe Herbicide label, EPA Reg. No. 10163-325 (EPA-stamped, Oct. 17, 2014).” www3.epa.gov/pesticides/chem_search/ppls/010163-00325-20141017.pdf (accessed 2026-10-06)