I want to expand the question. Last year someone suggested I apply liquid fertilizer to encourage top growth, wait a few days and then apply round-up around the base of the plant, where it will be absorbed.

I had my doubts. Roundup does need to be applied to the leaves, since that is where it is aborbed....not through the roots.

I can see that the fertilizer might cause the topgrowth to grow, and then there would be more area for absorption of the chemical.

However, what a laborous job, applying roundup to all the onion sprouts. And if you spray, it would kill the surrounding grass. You gotta do what you gotta do. What about applying straight roundup with a sponge to the onion tops? Wouldn't there be less "lateral" damage?

Hope someone knowledgeable will take the time to respond!
Thanks, Marie

Your idea of direct sponge, "swipe", or "wick" application of Roundup is a labeled use and works well when there is nearby desirable foliage that would be affected from overspray.

Now that the onion tops are about 12" tall, I googled "wild onions in lawn killing" there are some informative answers. The solution (literally) seems to be Weed B Gone, and determination with multiple sprayings, mowing, vigilance. By the time many of us notice, the infestation is too great for hand pulling.
Marie

The simplest and least expensive, and most environmentally friendly, method of control of these and any other unwanted plant is to dig them from the soil. For wild onion or garlic in flower beds cover the soil, where the desireable plants are not growing, with a mulch is efective. The only plant poisons that will work on these types of plants are those that will kill any other plant they touch, so great care, in addition to expense, is necessary when using them.

Gardenj, how did this stuff get into your beds in such an amount that it's now too much to dig/pull up? New-to-you location? New bed of too-thin lasagna? Border failure? Mowing in the wrong direction too close to the bed? That's obviously not what you want in your flower bed, and if possible, I would like to help you figure out why it's there so you can avoid having this problem again.

Ryanbuda, the link you provided seems like a commercial from Scott's, and fails to mention the botanical name of the plant in question. A handy oversight when one is trying to sell a product to anyone who thinks they have "onion grass that is ruining their lawn."

Lawn? Is another type of soft green plant growing with your grass really bothersome, or is that just a belief from being told it's supposed to bother you, a problem for which one must buy poisonous potions? Why worry about which "green things" one is mowing down to a few inches high? "Before I cut it down, I want to make sure it's all just one plant." A concern I'll never understand, even if I had all the time in the world. Strangely, believers of this are often the same people who bag the clippings and leaves, then pay for fertilizers to replace the lost nutrients, water to prevent the shallowly-rooted grass from dessicating, and aeration because of the lack of organic matter (and therefore the earthworms, microbes, etc...) in the soil that keep a soil healthy and spongy. ...which then grows a nice healthy lawn. ...because they want a nice healthy lawn.

On the lighter side, no matter how you feel about lawns and/or onion grass, this has GOT to make you laugh!.