You have no research to lean on here. No extension source in this research evaluates vinegar for nutsedge, so any promise that it works, or that it fails, is a guess dressed up as advice. UC IPM does list what a home gardener can buy for this weed. It names four actives. Glyphosate is one and halosulfuron is another, and vinegar is not on the list, so no honest claim about results goes in either direction.
The shoots were back in the same spot inside two weeks, standing taller than the grass around them. I had sprayed the tops in the low corner of my own yard, the clay patch that stays wet two days after rain, and the leaves browned off by morning. I pulled one of the new plants and the stem snapped off below the soil line. UC IPM puts the reserves a tuber spends on its second plant at 20% of its stores, which covers a fresh set of leaves with room to spare.
That regrowth has a route you can point at. Nutsedge builds tubers on rhizomes 8 to 14 inches (20 to 36 cm) down, and most of them sit in the top 6 inches (15 cm). Your spray lands on leaves. Nothing in this research describes a home remedy soaking down that far. Clemson adds that tubers stay dormant and viable for several years, and they do not all wake up in the same season.
There is a gap between a weed that looks dead and a weed that is dead, and sedge lives inside that gap. Anything that browns foliage buys you a tidy bed for a few days. A tuber is a storage organ with one job, which is to push up another plant once you take the last one off. So judge your treatment by what stands there three weeks later, not by how the patch looks the evening you spray.
The method the research does support works on that same tuber bank, and it is dull. A tuber spends 60% of its reserves raising the first plant and 20% on the second, so every shoot you take off costs the tuber more than it earns back. Pull or cut your plants before they reach the 5-to-6-leaf stage, which through summer means walking that spot every 2 to 3 weeks. Natural nutsedge control is a schedule you keep, and each round leaves less in the bank.
Give your routine a full season before you rate it. Tubers do not break dormancy together, so a patch you clear in June can send up a new flush in August. Watch your count of shoots per visit rather than whether the ground looks bare. A falling count tells you the bank under your feet is draining.
Fix your wet spot while you are at it. Sedge gets its head start where the ground stays soggy, so a leaking sprinkler head, a low corner, or heavy clay that holds water after rain is doing half the work for it. Regrade the dip, cut the run time on that zone, or swap the head out. Your grass competes better on ground that drains, and thicker turf shades young shoots before they get going.
A specific acid strength gets passed around online as the home remedy weed killer for sedge. That number traces back to commercial blogs, not a university trial, so you will not get it from me. Vinegar for nutsedge stays unrated here in either direction. In your lawn or your beds, keep taking the shoots off before they hit the 5-to-6-leaf stage, because that part has real research behind it.
Read the full article: Nutsedge: How to Kill It and Keep It Out
