It won't "throw" dirt. The tiller breaks the soil up and the furrower acts like a V-plow and pushes the dirt to the side. As long as the corn isn't spaced too far apart, it will hill it. I'm only marginally impressed with the hiller/furrower and don't use one myself... I don't have one, but a disk hiller might be a better option. This unit bolts in place of the tiller (not behind it), and it uses fully adjustable disks to roll dirt exactly where you set it to go.
The biggest problem with the BIO-80, BIO-100, and BIO-150 is the small throat for chipping. They're fine if you're chipping long, straight branches with few limbs, but get very aggravating doing large amounts of limby or twisted branches. I'm very impressed with the BIO-90. I sold one to a fellow with an apple orchard in northern Wisconsin this spring. When he came down to get it, we took it out to my couple of apple trees and pruned them. Both he and I were instantly in love with the BIO-90. You gotta be smart about using it, though. It has a huge throat that allows you to drop twisty, limby stuff in it without snagging. This throat will also will allow you to drop a 5 inch branch in it, but the capacity is 2.5 inches on hardwoods. You'll smoke the belts, then kill the engine if you push it too hard. Also, it will not tolerate wet material - branches with leaves are fine, but corn stalks and raked leaves are a big no-no. Frankly, a flail mower is a far more efficient tool for green garden waste, anyway. My goal is to be debt free this year in the Grillo business and my reward will be a cement floor in the garage and a BIO-90.
