The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- Glyphosate (isopropylamine salt in most consumer concentrates) (CAS 1071-83-6)
- Chemical class
- Non-selective, foliar-applied herbicide sold as the acid and several salts.[1]
- Mode of action
- WSSA Group 9: EPSP synthase inhibitors (shikimic acid pathway)[3][1]
- Signal word
- Glyphosate 41% Super Concentrate Herbicide (sold as Compare-N-Save Concentrate Weed & Grass Killer and other brands): Warning[2]
How it works
Glyphosate stops the shikimic acid pathway, an enzyme pathway that plants and some microorganisms need to make certain proteins.[1]
It binds tightly to soil, is broken down by soil bacteria, can persist up to 6 months depending on soil and climate, and is not likely to reach groundwater.[1]
Timing a spray
Spray when weeds are actively growing, the temperature is above 60°F and no rain is forecast for 24 hours; the label calls it rainproof after 2 hours, with visible results in 2 to 4 days and complete kill in 1 to 2 weeks.[2]
Hard-to-kill brush such as blackberry, kudzu or poison oak may need a second application, and brush sprayed in fall may not be fully controlled until the next season.[2]
Where it is used
It kills all green plants it contacts, lawn grass included, so shield desirable plants with cardboard or plastic and spray only in calm air; rinse off any plant you hit by accident right away.[2]
Flower beds, trees and shrubs can be planted 1 to 3 days after the last application; weeds treated around fruit or nut trees or grapevines need 21 days before you eat the fruit or nuts.[2]
Do not mix, store or spray it in galvanized or unlined steel containers.[2]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Glyphosate 41% Super Concentrate Herbicide (sold as Compare-N-Save Concentrate Weed & Grass Killer and other brands)[2] | Ragan and Massey, LLC | 84009-27 | 41.0% | soluble concentrate | Warning |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Glyphosate 41% Super Concentrate Herbicide (sold as Compare-N-Save Concentrate Weed & Grass Killer and other brands) | Tank sprayer: driveways, walks, fence lines, beds and areas being prepared for planting | Annual weeds (low end) to perennial weeds and brush (high end) | 1.5–2.5 fl oz per gal of water[2] 1.5 fl oz (3 Tbs) per gallon for annual weeds, 2.5 fl oz (5 Tbs) for perennials, brush and lawn renovation; a gallon covers about 300 sq ft. For a 24 oz hand-trigger bottle, 2 tsp (annuals) or 1 Tbs (tough weeds). Use the mix within 2 weeks. |
How to apply it, step by step
1. Protective gear
- Wear safety glasses: the concentrate carries a WARNING because it can cause substantial but temporary eye injury.[2]
- Keep it off your clothing, avoid breathing the spray mist, and wash with soap and water after handling.[2]
2. Before you spray
- Remember it kills nearly every green plant it touches, lawn grass included, so never use it for spot-treating weeds in a lawn.[2]
- Pick a warm, sunny, calm day above 60°F with no rain forecast for 24 hours, and shield nearby plants you want to keep with cardboard or plastic.[2]
3. Mixing
- In a tank sprayer, mix 1½ oz (3 tablespoons) per gallon of water for annual weeds, or 2½ oz (5 tablespoons) for perennial weeds, brush and lawn renovation; a gallon covers about 300 sq ft.[2]
- For a hose-end sprayer, put the concentrate in the jar without adding water and set the dial to match the rate. Close the cap tightly after use.[2]
4. Applying
- Spray while weeds are actively growing, wetting the leaves evenly; if you hit a plant you want to keep, rinse it off with water right away.[2]
- Reapply if it rains within 2 hours; after that, rain or watering won't wash it off. Tough weeds such as bermudagrass may need a second application if they regrow.[2]
5. After you spray
- People and pets may go into treated areas once the spray has dried.[2]
- Expect the first symptoms in 2 to 4 days and a complete kill in 1 to 2 weeks; large, established weeds can take up to 4 weeks.[2]
First aid
- If inhaled, move the person to fresh air and call 911 if they aren't breathing. For a medical emergency, call poison control at 1-800-222-1222, with the label in hand.[2]
Storage, spills and disposal
- Store it in the original container in a safe place out of direct sunlight.[2]
- Put an empty container in the trash or recycling; for a partly full one, call your local solid waste agency, and never pour unused product down a drain.[2]
From the safety data sheet
- The SDS uses the signal word Warning: the concentrate causes serious eye irritation, is harmful if inhaled and is toxic to aquatic life.[4]
- If it gets in the eyes, hold the eye open and rinse slowly and gently with water for 15 to 20 minutes, taking out contact lenses after the first 5 minutes, then call a poison control center or doctor; get medical attention if the irritation persists.[4]
- If someone breathes in the spray, move them to fresh air and call a doctor or poison control center if they feel unwell; if the person isn't breathing, call 911.[4]
- Clean up spills right away and keep people and animals out of the area: soak up a small spill with dry sand, vermiculite or another inert absorbent, put it in a waste container, then scrub the spot with detergent and water.[4]
- Store it in the original container out of direct sunlight, away from heat and flame, and above 10°F so it doesn't crystallize; the SDS lists galvanized and unlined steel as incompatible, so don't mix or store it in containers made of them.[4]
Safety and environmental hazards
People
This concentrate carries the signal word WARNING: it causes substantial but temporary eye injury and is harmful if inhaled, so wear safety glasses and avoid breathing spray mist. Regulators in the U.S., Canada, Japan, Australia and the EU and the WHO/FAO pesticide residue panel concluded glyphosate is not likely to be carcinogenic, while a committee of the WHO's International Agency for Research on Cancer, reviewing fewer studies, called it probably carcinogenic.[2][1]
Pets
The label says people and pets may enter treated areas after the spray has dried. Pets can be exposed by touching or eating plants still wet with spray, and exposed animals may drool, vomit, have diarrhea, lose appetite or seem sleepy.[2][1]
Bees and pollinators
The label carries no bee warning. NPIC notes that glyphosate can affect wildlife indirectly, because killing the plants changes their habitat.[2][1]
Fish and water
Pure glyphosate is low in toxicity to fish, but some glyphosate products can be toxic because of their other ingredients; keep spray and runoff out of storm drains, ditches and surface water.[1][2]
Common questions
- How long does glyphosate need before it rains?
- Two hours. The label says reapply if it rains within 2 hours, and that rain or watering after that will not wash it off.[2]
- How soon can I plant after spraying glyphosate?
- This label allows planting flowers, trees and shrubs 1 to 3 days after the last application.[2]
- Does glyphosate cause cancer?
- Most regulatory agencies, including EPA, concluded it is not likely to be carcinogenic; the WHO's cancer research agency (IARC) classified it as probably carcinogenic after reviewing fewer studies.[1]
- Is glyphosate dangerous to my eyes?
- This 41% concentrate is labeled WARNING because it can cause substantial but temporary eye injury; wear safety glasses when mixing and spraying.[2]
Sources
- National Pesticide Information Center, “Glyphosate General Fact Sheet.” npic.orst.edu/factsheets/glyphogen.html (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “Glyphosate 41% Super Concentrate Herbicide label, EPA Reg. No. 84009-27 (EPA-stamped, Nov. 12, 2019).” www3.epa.gov/pesticides/chem_search/ppls/084009-00027-20191112.pdf (accessed 2026-10-06)
- Weed Science Society of America, “Summary of Herbicide Mechanism of Action According to the Weed Science Society of America.” wssa.net/wp-content/uploads/WSSA-Mechanism-of-Action.pdf (accessed 2026-10-06)
- Ragan & Massey, Inc., “Farm General Grass & Weed Killer 41% Glyphosate Safety Data Sheet (Ragan & Massey, version 1.0, effective December 22, 2017; EPA Reg. No. 84009-27, the same registration as the page's Glyphosate 41% Super Concentrate Herbicide, sold under another brand name).” www.raganandmassey.com/wp/wp-content/uploads/2020/04/FG_84009-27_SDS.pdf (accessed 2026-10-19)