So how does this extreme exfoliation hit weeds, but not the crop you're trying to protect? Strangely enough, Forcella's weed-killing method, called "Propelled Abrasive Grit Management," is indiscriminate. You do hit your crop, but the idea is that you use the technique on hardier crops that won't sustain too much damage. Forcella has published a peer-reviewed paper that found his grit-blaster doesn't harm corn, and results in higher corn yields than weeding by hand. Another researcher, Sam Wortman at the University of Illinois, has found Forcella's method works with tomato and pepper plants, the Star Tribune reports.