Rice hull or husk material is the case or chaff of the rice. It is a byproduct of the rice you purchase at the grocery store. The hull is then compressed into a bag and sold to growers for use in their operation.
Rice hull material is typically sold in 50lb bags or 30 cubic foot sacks. The 50lb bags are then put 16 on a pallet. This size is manageable for a machine operator to load in the field. The 30 cubic foot sacks weigh near 700 lbs and require a machine to move. They should be left for applications that utilize a large hopper where the sacs can be easily and safely unloaded.
Here are two suppliers selling PBH rice hull material:
Griffin Greenhouse Supplies
The issue of weed prevention is a persistent and ongoing issue in agriculture. There are many options available for the grower. Some common solutions are: Bark mulch, pre-emergent herbicide, hand weeding, coir disks, herbicides. There are both advantages and disadvantages to all of these solutions.
A rice hull blower is a specialized machine that feeds rice husk from a hopper through a flexible hose and allow for dispensing to a precise location such as a container. The machine is on wheels and is meant to be towed behind a nursery wagon. Material is loaded into the hopper via an operator. The material then feeds through a device called a rotary airlock. This rotary airlock is a device that has large steel vanes welded to a shaft. The outside of the veins run closely to the case to provide an airtight seal. As the shaft rotates, material falls into the gaps between the veins and is carried to the bottom of the airlock where it falls into a pressurized air stream. This air stream delivers the material through the hose and out to the desired location. At the end of the hose is a device called a diffuser which is simply a larger area pipe. This larger pipe reduces the airspeed and allows the rice hulls to fall out of the end of the pipe instead of acting as a jet and blowing material out of the container.
The rice hull blower is for growers that have a need to dispense rice hull material in the field. Dispensing in the field allows time for the container media or soil to settle. It also allows for the operator to re-apply hull when necessary and does not require the rice hull to be applied in conjunction with inline potting.
Growers that are looking for an alternative to currently available weed prevention methods.
Growers that is looking to reduce their chemical usage and dependency.
Growers that are planting in the field and are unable to run a machine in line with a potting machine.
Growers that are applying rice husk by hand.
Growers that have non-circular pots, utilize trays, or have special containers or processes that prevent rotating containers on a conveyor line.
There are other options for applying rice hulls to containers in wholesale shrub nurseries. Different rice hull topper systems and equipment are available that applies rice hull as part of the potting conveyor line. This device rotates the pot as it goes through the machine. Material is loaded into the hopper directly under the potting line or behind the convey line and requires 110v or 220v power source. There are also some growers that apply rice hull by hand.
Pneumatic conveying is split into two types – Dilute and Dense Phase conveying. These phases refer to the ratio of material to move and the amount of air. Dilute phase has a high volume of air whereas dense phase utilizes high pressures and lower airflow. The rice hull blower solution operates in the dilute phase moving material quickly through the hose. Pneumatic conveying relies on a pressure difference between the beginning and end of the hose. This pressure differential “pushes” the material through the hose.