Each time hemp is washed it constantly reveals new surfaces, usually becoming softer with use. Given reasonable care it will render a lifetime of service.
Hemp fabric rapidly absorbs moisture - which accounts for its coolness and comfort when used for apparel or bed sheets. It is also one of the only fabrics which are stronger wet than dry, so it does not become tender through washing.
Generally speaking, dry cleaning is recommended for drapery hemp, upholstery hemp, decorative hemp, and high end garments.
If you are washing plain hemp fabric that has not yet been made into a garment, then it is very important to surge the edges before wash to prevent fraying.
As with other textiles, always test for color fastness and remember that detergents containing Optical Brightening Agents (OBA) may cause colors to alter slightly and will detract from the appearance of the subtle natural hemp. Bleach should not be used as it can significantly degrade and weaken the natural fibers.