Gly Star 5 Extra (2.5 Gallons) Glyphosate Concentrate...53.8

The Verdict

If you’re tired of paying triple for half-strength weed killer in a spray bottle, this 2.5-gallon jug of Gly Star 5 Extra is the grown-up choice. At 53.8% glyphosate — the same active ingredient as Roundup but at roughly double the concentration — this is the stuff farmers actually buy, repackaged for serious homeowners.

What’s actually in the jug

You get one 2.5-gallon container of amber liquid concentrate. No sprayer, no measuring cup, no gloves. Just the chemical. That’s fine — you’re not paying for plastic junk you’ll throw away. The label calls for mixing 2 to 3 ounces per gallon of water for most weeds, which means this single jug stretches to roughly 80–100 gallons of finished spray. For reference, that’s enough to treat a quarter-acre of dense vegetation, or about 20,000 square feet of driveway cracks and fence lines.

How it performs in the real world

Glyphosate works by disrupting the shikimic acid pathway — essentially, it blocks the plant’s ability to produce essential amino acids, and the plant starves from the inside out. What that means practically: you’ll see yellowing within 3–5 days on most annual weeds, and complete browning in 7–14 days. Perennial monsters like bindweed, Canadian thistle, and poison ivy will need a second application after 3 weeks, because the first pass kills the top growth but the roots can regenerate.

One buyer put it bluntly: “I sprayed a fence line full of poison ivy and blackberries. Two weeks later it was crispy brown. Nothing survived. This is the real deal, not the watered-down stuff from the big box store.”

That tracks with my research. The 53.8% concentration means you’re applying more active ingredient per drop, which translates to faster visible results and better root kill — especially on tough perennial weeds that laugh at 41% homeowner formulas.

What buyers consistently praise

The value proposition is the headline. Multiple reviewers note the price per ounce of active ingredient is roughly half what you’d pay for Ortho or Roundup concentrate. One long-time user said: “I’ve used this for 3 years on my 5-acre property. One jug lasts me two seasons. The per-acre cost is unbeatable.”

Coverage is another recurring theme — the 2.5-gallon format is the sweet spot between the tiny 32-ounce bottles and the bulky 5-gallon farm jugs that are awkward to pour and store.

Where it falls short — be honest with yourself

First, this is not a selective herbicide. One drift of spray onto your prized hydrangea and it’s toast. Don’t spray on windy days, and use a shield if you’re anywhere near desirable plants.

Second, there’s no surfactant in the mix. On waxy-leaved weeds like poison ivy or mature broadleafs, the spray beads up and rolls off. Add a non-ionic surfactant (about $10 for a bottle that lasts years) to your tank mix. Several reviewers mentioned this exact issue — “Works great on grass and dandelions, but I had to add dish soap to get it to stick to the burdock.”

Third, the smell. It’s pungent, chemical, and unmistakable. Wear a respirator if you’re spraying for more than 15 minutes. This isn’t a pleasant garden chore — it’s a chemical application.

Who should buy this

This is for you if: you have a large property with established weed problems, you’re maintaining a fence line, gravel driveway, or pasture edge, or you’re a farmer/rancher who needs bulk herbicide at a sane price. It’s also ideal for folks managing invasive species like kudzu or Japanese knotweed.

Skip it if: you have a small suburban yard with spot weeds — you’ll never use this much, and the concentrate requires careful measuring and mixing that a pre-mixed spray bottle sidesteps. Also skip if you have pets that roam the yard constantly; glyphosate is safe once dried, but wet spray is hazardous.

Three questions shoppers actually ask

Is this the same as Roundup?

Chemically, yes — the active ingredient is glyphosate, same as Roundup. But Gly Star 5 Extra is 53.8% concentration versus Roundup’s typical 41%. You use less product per gallon, and it’s a generic, so you avoid the brand markup. It’s not identical — Roundup has proprietary surfactants — but for most uses, it’s functionally equivalent at a fraction of the cost.

How do I mix it?

For most weeds: 2–3 ounces per gallon of water in a pump sprayer. For tough perennials or dense brush, go to 4 ounces per gallon. Add a surfactant at 1 teaspoon per gallon. Spray to wet, not to runoff. Wear gloves, long sleeves, and eye protection. Mix only what you need — the concentrate stores fine, but mixed spray degrades within 24 hours.

How long until I see results?

Visible yellowing in 3–5 days on annuals. Complete browning in 7–14 days. Perennials like poison ivy or thistle may need a follow-up application at 3 weeks. Don’t pull weeds until they’re fully brown — you want the glyphosate to translocate to the roots first.

The verdict

Gly Star 5 Extra is a no-nonsense, farm-grade herbicide that delivers on its promises. It’s more potent, more economical, and more effective than anything you’ll find in the garden center aisle. The tradeoffs — no surfactant, strong odor, and the need for careful handling — are manageable for anyone who reads the label.

Buy it if you’ve got serious weed problems on serious acreage and want professional results without the professional price tag.

Skip it if you need one bottle for spot-treating a small lawn, or you’re not comfortable handling concentrated chemicals.

Rating: 4.6/5 — loses half a star for the missing surfactant and the aggressive odor, but the performance and value are undeniable.

Where to Buy

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Last updated: 2026-08-06. Ratings and prices current as of review date. Verify on Amazon before purchasing.