Study: Rice Hull Effect On PGRs Comparable To Perlite

Greenhouse growers can substitute rice hulls for perlite in their media without the need for an increase in growth regulators, according to a Purdue University study.

Growing media for ornamental plants often consists of a soilless mix of peat and perlite, a processed mineral used to increase drainage. Growers also regularly use plant growth regulators to ensure consistent and desired plant characteristics such as height to meet market demands. Organic substitutes for perlite like tree bark have proven difficult because they absorb the plant-growth regulators and keep them from getting to the plants. Using bark requires a 25 percent increase in the volume of growth regulators applied.

"We were not sure whether rice hulls, as an organic component, would hold up the growth regulator," says Roberto Lopez, a Purdue assistant professor of horticulture and co-author of a “HortTechnology” paper that outlined the findings. "Testing showed that there were no differences in plants grown with rice hulls or perlite."

Pansies and calibrachoa were planted in an 80-20 mix of both peat and perlite and peat and rice hulls and then treated with several different growth regulators. The plants treated with and without growth regulators and grown in peat and perlite and peat and rice hulls had similar heights and stem lengths.

Finding a waste product to replace perlite could reduce the price of growing media because perlite must be mined and heat processed.

"It’s a really energy-intensive process and, because it’s a mineral, it’s non-renewable," says Chris Currey, a horticulture graduate student and co-author of the “HortTechnology” paper.

Rice hulls are an attractive option, Lopez says, because they can be easily transported on barges and rice growers in the South could increase profits by selling a traditional waste product.

"Often these rice hulls were being burned because there’s not a lot of other use for them," Lopez said.

Syngenta and Fine Americas funded the research. Lopez and Currey collaborated with Purdue research technician Diane Camberato and graduate student Ariana Torres.

Leave a Reply

16 comments on “Study: Rice Hull Effect On PGRs Comparable To Perlite

  1. I worked with a large greenhouse (over 10 acres)that converted to rice hulls from perlite to be organic. The company that the greenhouse bought the rice hulls from changed the way they processed the rice hulls. This process change caused the rice hulls to break down prematurely which in turn caused the soil to rob nutrients from the plugs/plant. The nurtient deficiency caused extensive stunting and plant loss and wreaked havoc on plant quality/availability.
    I understand another greenhouse lost their entire plug crop of Mother’s Day annuals. Be very careful–test on a small scale. The greenhouse I worked with has converted back to perlite….

  2. Fresh par boiled rice hulls do not break down prematurely. Excessive starch content robs soils of nutrients-and this issue has been addressed. Rice hulls are composed of lignin fiber, carbon and silica. Clean fresh par boiled hulls do not cause nitrogen problems. Rice hulls hold water differently that perlite-drying on the surface quicker-and often fool waterers to water prematurely. Growers have been successful when new products are embraced and adapted to. Rice Hulls are not perlite, and vice-versa. All changes in growing media require some adjustment in growing practices.

  3. The problem was that the rice hull processor was NOT using fresh water each time. They were recycling the same old water which lead to the faster break down and other problem. This processor had ALWAYS used fresh water in the past and for “cost savings” changed to reusing the same water—know one knew or was notified….growers lost hundreds of thousands of dollars from this one change… I understand new products take adjustment but when processors do not tell you about changes they make it makes you VERY hesitant to change…..This is a quality/trust issue.

  4. Growers may be able to squeak by using rice hulls in “grow it up and push it out the door” production. Rice hull compatibility with PGRs is fine for the producers of plants who are looking to reduce costs and attempt to be more “earth friendly”, but plants do NOT do well long term in this media. My observation is that hanging baskets and container gardens planted in this media WILL FAIL by mid-summer. Pretty much anything that is grown in rice hull media that is not planted into real soil or a non rice hull soilless mix by the customer will also FAIL. Customers DO get angry and tell all of their friends and family about their experience. They DO blame the garden center who sold it to them. They DO NOT know nor care about the difference in media types and if they need to do anything “special” to keep their investment alive. All they know is that they wasted their money and eventually will give up on plants and spend their money elsewhere.

  5. Maybe your hanging baskets failed because you had too much porosity(drainage). What about the peat? Peat is the main water holding source in a mix. What about the wetting agent?. Rice hulls have been used for many years by many growers who produce quality crops. I don’t agree that plants don’t do well long term. I’ve seen too many successful crops. The rice hull media plants I bought at Lowe’s this Spring lasted all Summer and Fall. Mr. Frost is going to have to get them. Rethink before you react.

  6. I worked with a large greenhouse (over 10 acres)that converted to rice hulls from perlite to be organic. The company that the greenhouse bought the rice hulls from changed the way they processed the rice hulls. This process change caused the rice hulls to break down prematurely which in turn caused the soil to rob nutrients from the plugs/plant. The nurtient deficiency caused extensive stunting and plant loss and wreaked havoc on plant quality/availability.
    I understand another greenhouse lost their entire plug crop of Mother’s Day annuals. Be very careful–test on a small scale. The greenhouse I worked with has converted back to perlite….

  7. Fresh par boiled rice hulls do not break down prematurely. Excessive starch content robs soils of nutrients-and this issue has been addressed. Rice hulls are composed of lignin fiber, carbon and silica. Clean fresh par boiled hulls do not cause nitrogen problems. Rice hulls hold water differently that perlite-drying on the surface quicker-and often fool waterers to water prematurely. Growers have been successful when new products are embraced and adapted to. Rice Hulls are not perlite, and vice-versa. All changes in growing media require some adjustment in growing practices.

  8. The problem was that the rice hull processor was NOT using fresh water each time. They were recycling the same old water which lead to the faster break down and other problem. This processor had ALWAYS used fresh water in the past and for “cost savings” changed to reusing the same water—know one knew or was notified….growers lost hundreds of thousands of dollars from this one change… I understand new products take adjustment but when processors do not tell you about changes they make it makes you VERY hesitant to change…..This is a quality/trust issue.

  9. Growers may be able to squeak by using rice hulls in “grow it up and push it out the door” production. Rice hull compatibility with PGRs is fine for the producers of plants who are looking to reduce costs and attempt to be more “earth friendly”, but plants do NOT do well long term in this media. My observation is that hanging baskets and container gardens planted in this media WILL FAIL by mid-summer. Pretty much anything that is grown in rice hull media that is not planted into real soil or a non rice hull soilless mix by the customer will also FAIL. Customers DO get angry and tell all of their friends and family about their experience. They DO blame the garden center who sold it to them. They DO NOT know nor care about the difference in media types and if they need to do anything “special” to keep their investment alive. All they know is that they wasted their money and eventually will give up on plants and spend their money elsewhere.

  10. Maybe your hanging baskets failed because you had too much porosity(drainage). What about the peat? Peat is the main water holding source in a mix. What about the wetting agent?. Rice hulls have been used for many years by many growers who produce quality crops. I don’t agree that plants don’t do well long term. I’ve seen too many successful crops. The rice hull media plants I bought at Lowe’s this Spring lasted all Summer and Fall. Mr. Frost is going to have to get them. Rethink before you react.

  11. Wow I just purchased several bales of PBH. I hope this "recycled water" issue has been taken care of and the batch I purchased is from fresh stock. I plan on using it as a perlite replacement. Switching from peat to coir also. I Think the changeover will go smoothly as long as the PBH performs as advertised. Can either of you who actually know the details of the problem let me know which manufacturer and time frame we are talking about here please.

  12. Were working with a vertical gardening system that provides mechanical root anchorage and do not need the caking properties of Peat Moss. We would like to see information about accelerating nitrogen lock up / decomposition. And what is the max % of rice hulls we might be able to go with. A picture should help. http://www.facebook.com /the vertical eco garden or http://www.verticalecogarden.com

Latest Stories
AFE Scholarship Video

August 16, 2017

Looking to Host an Intern This Year? Consider AFE’s Sch…

The American Floral Endowment is accepting applications for its Vic and Margaret Ball Intern Scholarship Program and Mosmiller Intern Scholarship Program until Oct 1. Interested companies can apply anytime to become a host employer.

Read More
Delta T Devices WET Sensor in Space

August 15, 2017

Greenhouse Environmental Sensor is Truly “Out of This W…

Delta-T’s multi-parameter WET Sensor has been used by Chinese astronauts aboard the Tiangong-2 Space Lab to cultivate lettuce plants within the weightless atmosphere.

Read More
griffin-expo

August 15, 2017

Griffin Becomes Newest Distributor for Master Nursery G…

The agreement allows Griffin to join Master Nursery’s network of more than 150 supplier partners, while giving Master Nursery access to new product and service options for member businesses in the Midwest, Rocky Mountain, and Pacific Northwest regions.

Read More
Tal Coley, AmericanHort Director of Government Affairs

August 15, 2017

AmericanHort Has a New Director of Government Affairs

Tal Coley, a U.S. Air Force veteran who has an extensive background in issues advocacy, will play an active role in AmericanHort’s upcoming Impact Washington event in September.

Read More
Recyclable Horticulture Plastic Containers

August 15, 2017

How to Know Which Plastic Containers You Can Recycle

Michigan State University’s Garrett Owen offers tips to help you properly dispose of plastic containers, flats, and trays.

Read More
Francis Kwong, PanAmerican Seed

August 15, 2017

Ornamental Seed Scientist Francis Kwong Dies at Age 65

Kwong was most recently the Director of Seed Technology for PanAmerican Seed, and his research was instrumental in the development of calibrachoa, angelonia, and other plants.

Read More
Laura Drotleff

August 15, 2017

Why Consumers May Be More Interested in Plants Than You…

A visit to a local lavender event is a reminder that when you tap into something consumers are excited about and want to experience, the reward can be long-lasting,

Read More
Three Sections of Vineland Research Centre

August 14, 2017

Canadian Greenhouse Conference Features Focus on Techno…

This year’s Canadian Greenhouse Conference kicks off on October 4, and there is no shortage of presentations devoted to how growers can implement new technology in their greenhouses.

Read More
Youngs Greenhouse Space Growing Feature

August 14, 2017

How Young’s Plant Farm Invests in New Structures and Eq…

The Auburn, AL-based Top 100 Grower operation is improving its production infrastructure so it can continue to efficiently produce quality plants and keep up with demand.

Read More
HOVE International Rolling benches on concrete

August 11, 2017

Greenhouse Bench Systems Designed to Handle Any Space

HOVE bench systems from HOVE International can accommodate multiple levels while allowing for run-off water collection.

Read More
DTH 800 (Link4 Corporation)-feature

August 10, 2017

New Sensors Can Help You Manage Your Greenhouse Crop 24…

The wrong environmental conditions in your greenhouse can potentially lead to significant crop loss. Here’s how sensor technology manufacturers are helping you safeguard your greenhouse.

Read More
LED toplighting, Runkle - feature

August 9, 2017

Lighting Technology Under the Microscope at Production …

Here’s a sneak preview of three lighting trends that will be discussed by Erik Runkle at the Production Technology Conference.

Read More

August 9, 2017

Vestaron

Vestaron’s Spear insecticides carry labels for control of thrips, white flies and spider mites on both greenhouse ornamentals and greenhouse vegetables.

Read More

August 9, 2017

Bayer

Bayer’s Altus insecticide can be used before, during and after bloom to control whiteflies, aphids and other sucking pests on a wide range of ornamental pests.

Read More

August 9, 2017

Jiffy

Jiffy’s orchid plug propagation system has been shown to deliver production time savings from 25% to 40% as the uniform substrate stimulates fibrous root growth throughout the plug.

Read More

August 9, 2017

Stockosorb

Stockosorb’s 660 is the company’s most advanced hydrogel product. It is easy to apply and it provides consistent soil moisture to minimize growers’ watering requirements and reduce shrink.

Read More

August 9, 2017

Scotts

Scotts’ Root Factory brand features a range of professional growing media products that offer high-performance mixes with perfectly balanced ingredients to offer cost savings and reduced production cycles.

Read More

August 9, 2017

Kemin

Kemin Industries’ TetraCURB is now labeled for all food crops (indoor and outdoor use) and comes in a wide range of packaging options to meet growers’ needs when battling mites.

Read More