Left: Rice hulls provide excellent control of bittercress and liverwort. Containers from left to right are topdressed with 1, ½, ¼ and 0 inches of rice hulls. (Research conducted by Dr. James Altland, a research horticulturist with the USDA-ARS in Wooster, Ohio.) Right: When topdressing with rice hulls, allow space at top of container at transplant and cover entire surface with one to two inches of PBH rice hulls. Circle: This photo shows oxalis seed (in red circles) on the rice hull topdressed container surface, still unable to germinate after six weeks. (Research conducted by Dr. James Altland, a research horticulturist with the USDA-ARS in Wooster, Ohio.)

Herbicides and hand weeding have long been the two options for managing weeds in nursery containers. In recent years, however, a new grower-developed technique has emerged and gained significant credibility. Nursery professionals have discovered the benefits of managing weeds by topdressing containers with parboiled rice hulls – a weed management practice now substantiated by USDA research.

Although rice hull topdressing may not totally eliminate the need for herbicides and/or hand weeding, it can reduce both and provides several other key advantages.

A rice hull top-dress of 1 to 2 inches offers the following:

  • Prevents airborne weed seeds from reaching the growing media and germinating
  • Dramatically decreases container weeds, including moss species such as liverwort
  • Significantly reduces hand-weeding labor and expense
  • Provides excellent potential for reduced herbicide use
  • Helps decrease damage in herbicide-sensitive plant material
  • Can reduce drought stress and watering
  • Costs just pennies per container
  • Provides economical, earth-friendly weed management
  • PBH rice hulls, a product of Riceland Foods, Inc., are the popular choice for topdressing nursery containers and currently in use at many nurseries. Uniquely processed to verify purity and cleanliness, these rice hulls are a readily renewable resource supporting sustainable production. PBH is OMRI Listed and WSDA registered, making it suitable for both organic and traditional production. PBH is available in a compressed 50-lb. standard bag or a compressed 30-cu.-ft. bulk bale.