PBH Nature’s Media Amendment is a uniquely processed rice hull product from Riceland Foods, Inc. with multiple uses in the greenhouse and nursery environment. In container nurseries, it has been used with much success to reduce weed germination. For pennies per container, growers can free up employees that used to spend lots of time hand weeding. PBH rice hulls do not absorb water, which makes them well-suited for container crops that require irrigation, even those with fertilizer piped in. They dry quickly after watering and resist decomposition. They have been proven to keep weeds like liverwort and bittercress at bay for up to 15 months, plenty of time for most container crops.
This weed control practice was developed by growers looking for a better way to manage container weeds, says Scott Johnson, commercial director with Riceland Foods Inc.
“When you topdress with rice hulls, you’re creating a barrier on top,” Johnson says. “As long as the weed seed cannot reach that media, it cannot get the seed to soil contact to germinate. Plus, there is not the moisture to sustain germination of the weed seed.”
The practice offers many benefits, but the primary reason growers have taken to topdressing with PBH rice hulls is to reduce costs. This includes reduced hand weeding labor cost, potential for using less herbicide – another major expense -- and minimizing damage to herbicide-sensitive plants. Also, it can reduce drought stress and the need for watering.
Researchers have tested PBH rice hulls as a container topdress. Dr. James Altland of USDA-ARS in Wooster, Ohio, has conducted several experiments measuring effectiveness of rice hulls in weed control. His research shows the rice hulls prevent weed germination, even when fertilizer is injected through the irrigation system.
Of course, PBH rice hulls can also be used to replace perlite as a container substrate. Many nurseries run greenhouse operations as well for propagation, and often use perlite in their growing mix.
Michael R. Evans of the Department of Horticulture at the University of Arkansas researched the use of parboiled fresh rice hulls as an alternative to perlite in horticultural substrates. In his research, Evans determined that incorporation of PBH rice hulls into Sphagnum peat-based substrates did not result in significant nitrogen tie-up, and parboiled fresh rice hulls were free of viable weed seed.
When incorporated into Sphagnum peat-based substrates, parboiled fresh rice hulls did not negatively impact the chemical properties of the substrate. In fact, parboiled fresh rice hulls provided equivalent or higher levels of drainage and air-filled pore space than perlite. Finally, Evans found that root and shoot growth was similar for plants grown in Sphagnum peat-based substrates amended with equivalent amounts of perlite or parboiled fresh rice hulls. Click here to read more about the use of PBH rice hulls as a substrate.
Tom Demaline, owner of Willoway Nurseries, Avon, Ohio, uses PBH Nature’s Media Amendment as both a container topdress and a media amendment.
“PBH gives us weed control from day one,” he says.
Willoway Nurseries has been able to reduce labor costs associated with hand weeding, which were quite substantial for a grower with four million containers in production.
“We topdress containers with PBH at potting to ensure season-long weed control and significantly reduce hand weeding,” Demaline says. “With increasing labor costs and unpredictable weather patterns, we were looking for just such a tool to supplement our herbicide program. We also use PBH in our mix to maintain porosity. It works two ways for us.”
Hernie Rosado, production manager at Ridge Manor Nurseries is another believer in the system.
“Topdressing with PBH rice hulls has been a game changer for our weed control program,” he says.
Ridge Manor Nurseries is a wholesale grower located in Madison, Ohio. Rosado’s team offers a full line of shrubs, perennials, grasses and trees in various container sizes. He says the tangible benefits of using rice hulls are very real, especially for large growers.
“By topdressing with PBH at potting we save time, reduce hand weeding and use less herbicide,” Rosado says. “Those are three big benefits for a nursery with thousands of containers in production.”
To maximize efficiency, containers should be topdressed with rice hulls at the time of potting. This should be the last stop in the process prior to watering. The rice hulls can be applied to the container surface by hand or with a topdressing machine suitable for this application.
The Riceland parboiled rice hull product, PBH Nature’s Media Amendment, is highly compressed when packaged in your choice of a 50-lb. standard bag or a 30-cu.-ft. bulk bale. This lowers freight costs, generates less waste and minimizes storage and handling.
The hulls themselves are is a natural by-product of rice and considered a renewable resource with much to offer greenhouse growers, nurserymen, consumers and the environment. PBH is OMRI Listed® and WSDA registered.
For more information: http://www.riceland.com/pages/rice-hull-products/