By: Julianne Mason, Restoration Program Coordinator, Forest Preserve District of Will County
We have been using rice hulls as a carrier for our native seedings and loving the results! I first got the idea to try rice hulls from this USDA technical note [link to https://www.nrcs.usda.gov/Internet/FSE_PLANTMATERIALS/publications/idpmctn11458.pdf] I’ve tried various carriers over the years, primarily cereal grains like annual oats and rye, but here’s why rice hulls seem to work well:
- Rice hulls are light and fly out of the broadcast spreader about as far as native seed. More aerodynamic carriers like annual oats fly farther and give the operator a false sense of how wide the native prairie seed is being spread;
- Rice hulls seem to keep very small seeds (like rushes, wool grass, etc.) from falling out of the seed mixture all at once, and make them more evenly distributed across the field. This is especially beneficial for wetland seed mixes, which tend to have a lot of small seeds;
- Since they are light, rice hulls are a much nicer carrier for hand broadcasting. Also, less weight in the broadcast spreader makes it less likely for pins to shear;
- For our minimally cleaned prairie seed, rice hulls help the fluffy, stick-filled mass of seed to flow better through the seeder, and they reduce bridging and clumping; and
- Rice hulls are cheaper than cereal grains, when you just need a carrier and not a cover crop.
Here in the Midwest, unbroken rice hulls are available in compressed 50 pound bales directly from Riceland or from various on-line distributors like A.M. Leonard. We’ve been using 10 pounds of rice hulls per acre as a carrier for initial seedings, and 5 pounds of rice hulls per acre for lighter overseedings. Also fabulous: mixing the seed and rice hulls in a concrete mixer, which works really well!
Caption: Sorting bags of seed for mixing.
Caption: We used to mix seed by hand, mixing it with pitch forks and shovels on a concrete floor. A very dusty job!
Caption: The rice hulls are compressed and expand when the bale is opened. I highly recommend putting the rice hull bale in a 55-gallon plastic drum before slashing the sides of the bale open with a knife.
Caption: Photo of our restoration ecologist, Nick Budde, loading native seed and rice hulls in the concrete mixer.
Caption: We keep a poly bag strapped over the mouth of the concrete mixer while the seed is mixing. It keeps seed and dust from flying out.
Caption: Once mixed, the seed and rice hulls are dumped out into the poly bag.
Caption: View of rice hulls mixed with very clean seed bought from a commercial nursery.
Caption: View of rice hulls mixed with our minimally processed native seed.
Caption: View of seed and rice hulls broadcast onto snow cover.
I’m not familiar with this work. It would be helpful if there was an introduction to the article explaining why you need any additional substance in with the seeds. What the advantages of it are. I’m also trying to understand the dynamics of using the two substances together, and I’m wondering has it been tested yet to the point where you know that the seeds do reach the ground and then sprout when they are broadcast using the hulls. Thanks
You make a good point about the post needing more context. Carriers are often used to make sure the native seed flows properly through the seeder, and is distributed evenly across the field. In my experience, carriers are important when using broadcast seeders, but I don’t know how necessary when using drop seeders or other types of seeders. For broadcast seedlings, rice hulls (or other carriers) act as an even-sized chaff which makes the medley mix of sizes and shapes of native seeds flow more evenly. Seeds and carrier are all lightly distributed on the ground surface, and the native seeds germinate irrespective of the presence of the carrier. No formal science on that, just casual observations. Thanks for your comment!
– Juli Mason
Great Job Julianne,
I have been using and selling the same product here in Ohio for the last five years, and they work well.
One important addition; You and I are using what is known as PBH or Par-Boiled Rice Hulls from Riceland Foods. They have indeed been cleaned and then boiled to kill of any weed seeds, so they are a very sterile product. If folks just ask for “Rice Hulls” they may get a product straight from the fields and full of “who knows what” weed seeds! Ask for “PBH”
I tried to buy rice hulls on-line, but the shipping cost was outrageous- three times as much as the product itself. Any advice on how to get this product for a lower cost? I live in Wisconsin.
Dean, you are correct that the shipping can seem outrageous. You need to buy at least a full pallet (16 bales) at a time to start to see some cost effectiveness. If you have large plant nurseries in your area, call them to see if they use “PBH”. Nurseries commonly use it to thin and loosen potting soils or to Topdress Mulch their container stock. The product also works great when tilled into your garden, really loosens up our hard Ohio clay. I typically sell a single bale for $16, and it can be shipped Via UPS. Still cheaper than wasting seed.
As far as cost of rice hulls and shipping I would recommend trying Pheasants Forever Seed store online for that. It’s very reasonable in regards to price and shippijng.
I have read that restoration groups have been using rice hulls as a carrier. It still amazes me that different places can get so much seed that they need a carrier. I usually get only a few hundred seeds of each species I focus on collecting. The things I collect include yellow star grass, violet wood sorrel, Seneca snakeroot, prairie phlox, smooth phlox, fringed puccoon, and hoary puccoon. I also work on sedges that are conservative and/or produce little seed like Carex crawei, Carex meadii, Carex richardsonii, Carex tetanica, and Carex umbellata. However, I only have the time to collect a fraction of these species in any given year. When spreading the seed I just place one seed at a time in a favorable looking spot in between established restoration vegetation. I choose placement of each seed carefully hoping to improve the chances for success and guarantee even distribution. It is hard for me to fathom the scale at which Nachusa and other places work. I can see how the concrete mixer would be perfect for mixing large seed mixes. I enjoyed seeing the pictures of the work happening. Thank you for writing this post and sharing your experiences with all of us.
what is a good ratio of rice hull carrier to wildflower seed?
carrier : seed = ?
I see you’ve got the application rate in your article. 10lbs/acre. I’m all set thanks.