I use the dirt itself to kill weeds. Look at the picture on the left and you will see a row of sweet corn with small grass growing in among the corn plants. I have run the tiller between the rows and loosened the soil and chopped up the weeds and grass growing there. So I go down the rows with a hoe and pull the dirt in around the corn plants to cover the small weeds growing there. It works pretty well. The broadleaf weeds and grass have to be fairly small and the corn has to be a few inches high. But you can hill the soil up around the corn. it likes the whole process.
I started doing this a long time ago after driving a cultivating field corn with a tractor. At the time I think I did 6 rows at a time. You go rather slowly with a cultivator behind the tractor that is a series of small shovels. They are spaced on a bar to work the soil between the rows right up to the plants. They also move the soil into and around the corn plants as you go along on the tractor. You adjust your speed and depth of the cultivator to make sure you do not bury the corn. Also you have to pay close attention to make sure the cultivator does not just dig out the corn as you go along so it is an arduous job to do all day long. Farmers don’t do any cultivating now. At least the ones around here don’t. They rely entirely on chemicals to kill weeds. But, that is a whole other story and I do not want to get started on that.
This method of cultivation will work with green beans, okra, onions, or anything big enough to have some dirt piled up around it. It does not work well for young carrots because they are too small. I usually crawl along on the ground and pick the weeds out of those.