It bears the shoot material that must be removed, traps soil at the junction with roots and needs to be chopped to produce uniform drying. There is still uncertainty about the best time to harvest valerian in New Zealand as it not only depends on the age of the root, but also on the growing environment and seasonal change. The present recommendation is to harvest in autumn with the tops cut to ground level before tile roots are lifted. A root crop lifter that is capable of working to 30 cm depth can be used. Dry soil conditions and mechanical shaking to remove excess soil is desirable before washing.
Subsequent washing using a rotary root washer is necessary to remove all soil.
Soil is held very tightly in the crown of the plant, and the root mass should be broken into smaller pieces to enable effective washing. Also, the separation of root and chopping the rhizome into smaller pieces is necessary to ensure uniform drying. The best method of drying to prevent enzymatic breakdown of the constituents is to dry the crop as rapidly as possible without overheating. Overseas study provides some direction. New Zealand studies are underway to verify these recommendations.