A good practice in planting hemp for fiber production is to sow around the edge of the field next to the fence a 16- to 18-foot width of small grains, which may be harvested before the hemp. Space is thus provided for the harvester to enter the field and begin cutting without injuring the hemp. It also prevents hemp plants at the edge from growing too rank. Uniform plants are necessary for uniform fiber quality.
Fall plowing in Wisconsin gives better results with hemp than spring plowing.
Hemp for fiber production requires little or no cultivation or care after planting until the harvest; but if, after seeding and before the seedlings emerge, the ground crusts badly it may be advisable to roll the field to break the crust. Hemp for seed production should be cultivated the same as corn; that is, sufficiently to keep back the weeds. Spudding out Canada thistles where they appear in dense stands in hemp fields should be done when the hemp is only a few inches high. In most cases hemp will compete well with weeds, if the hemp gets off to a good start.
Varieties to grow
The fiber hemp grown in the United States by the early colonists was of European origin; but our present hemp, commonly known as Kentucky or domestic hemp, is of Chinese origin. Few importations of hempseed have been made in recent years for commercial plantings, as imported seed has not proved as productive under domestic conditions as Kentucky hemp.
Enemies
In the United States there are no hemp diseases of economic importance, and hemp has not been seriously attacked by insects. The European corn borer and similar stem-boring insects occasionally kill a hemp stem. However, they have not proved important, perhaps because hemp has not been grown to any extent in the sections of the United States where the European corn borer is a serious pest. Seedling plants are frequently attacked by cutworms and white grubs after spring plowing of sod land.