The farmer's job is done when he delivers the hemp to the mill. All further processing to prepare the fiber is part of the milling operation. However, it is of interest to both farmers and mill operators to attempt to keep the hemp stalks and fiber well butted. This means keeping the butt ends of the stalks or fiber in a bundle all even. Every time the hemp stalks are handled, care should be taken to see that this is done. If the hemp stalks are well butted in the bundle when processed, the milling operations can be carried out more economically. Tangled, uneven bundles are more difficult and require more time to handle. The yield of high-value long-life fiber is much greater if the stalks are well butted.

Hemp stalks are considered most desirable if they are less than half an inch in diameter. The thickness of a pencil is frequently used to illustrate the size of desirable stalks. The larger diameter stalks have a lower percentage of fiber than finer stems, are harder to break, and produce more tow fiber.

Hemp stalks grown on unproductive soil usually contain a lower percentage of fiber, and this fiber may be coarse, harsh, and of low strength, so that it breaks into tow in milling.

Stalks underretted frequently must be run through the mill breaker a second or third time to remove the remaining hurds. This increases the milling labor costs, and the resultant fiber may be reduced to a low grade. On the other hand, overretted hemp must be milled as little as possible, with less pressure exerted on the rollers and a slower speed of the scutcher wheel to keep from making an excess amount of tow fiber.