Soils Alive Blog

The Corn Gluten Meal Question

Posted by Michael Bosco on Wednesday, March 12, 2008

About every fourth yard we visit, the homeowner has applied corn gluten meal the previous Fall, and is completely puzzled about why he or she has so many weeds. The most common comment from is, "I think I caused a bigger weed problem, look I have more weeds than my neighbor and they didn't apply anything". The sad thing is I know exactly how they feel. Soils Alive used cgm for more than 5 years trying to get it to work. We always thought our timing was off or it was not a good product so we would change suppliers, but every year we had many client calls wondering why their weeds were so bad.

The reality is they are absolutely right; they did cause a larger problem when they applied corn gluten meal in the fall. Why you ask? To answer that we have to understand how corn gluten works. Dr. Nick Christian at Iowa State University discovered the pre-emergent qualities of cgm and later Dianna Liu as a graduate student at ISU eventually isolated the five individual dipeptides (combinations of two amino acids) that had the ability to inhibit root formation of germinating seedlings.

It is important that we understand that cgm does not inhibit germination, it inhibits root formation. For cgm applications to be successful it must be applied 2-3 weeks before seed germination, watered in sufficiently then all irrigation shut off to allow the soil to dry out. This allows seeds to germinate then given time to desiccate before the next rain/water occurrence. If the soil is moist after the point which the cgm's effectiveness is degraded then the weed seedling will produce roots and will "grow out" of the cgm. If this scenario occurs then the weed seed will have the benefit of the cgm's10 nitrogen allowing it to grow faster, taller, and stronger than if nothing was applied.

The fall/winter application of cgm in my opinion is not a good horticultural decision, and does not provide effective weed suppression. The reason it is not a good horticultural practice is because 20 lbs of cgm per 1000 sq. ft. is the equivalent of 2 lbs of nitrogen at a time when plants are naturally going dormant. That amount of nitrogen will stimulate freeze prone tender growth instead of allowing the plant to harden-off for the winter. Also high nitrogen applications increases the chance St. Augustine grass will succumb to fungal disease, such as brown patch. The weed suppression does not occur as advertised because in the DFW area weeds germinate for several months in the fall and late winter. This would require an application of cgm every 3 to 4 weeks to effectively inhibit the roots from forming. When you add on the challenge of needing a dry period to allow for the desiccation of the weeds then chances are cgm is not going to deliver as advertised.

When should Corn Gluten Meal be used? The only time I would recommend using cgm would be in the spring as the grass is greening up. This application supplies the grass a shot of nitrogen so that it greens up quickly, increasing its density and height so that it can physically out compete the weeds. This approach is the most effective weed suppressing tool there is, physical competition. Any weed suppression the cgm offers is a bonus and thus not a waste of money or labor. I still have a but to inject here. Cgm is composed mostly of nitrogen, containing little to no phosphorus, or potassium. This makes cgm a very "white bread" sort of diet for the plants, and not a well balanced product that feeds the soil and plant in a holistic manner.

I am not a fan of corn gluten meal; it is a by product of the corn syrup industry, and is sold as an animal feed commodity so the price is always higher than products that are waste products that should be used as fertilizers. I think cgm was born out of advertising hype, and a need for an organic weed control. My hope is that we will soon have effective tools that stand up to field trials and not just laboratory studies. Maybe ISU will be able to isolate the effective portions of cgm and create a stable organic weed preventative that has longevity in the field.

Category: General  |  Comments (0)

The Soils Alive Blog

Posted by Michael Bosco on Tuesday, March 04, 2008

The Soils Alive BlogWelcome to Soils Alive's new blog - a place for stories, anecdotes, questions and answers to organic lawn care related issues. Please sign up to comment or to ask a question. We welcome your input. Thanks!
- Michael

Category: General  |  Comments (0)

March: Back to life

Posted by Michael Bosco on Saturday, March 01, 2008

The month of March brings plants springing back to life. Gardeners begin setting out tender plants after the 15th of March which is considered our last potential freezing day.

We will begin apply our Round 2 application in March, which is a dry organic fertilizer, and Liquid Compost. Our two step application is very important to feed the soil that will in turn provide plant nutrients for healthy spring growth. It is critical here in north Texas to get off to a good start, because we have four months to create happy plants before the summer stresses of heat and lack of rain start.

Environmental stresses are reduced with an organic program by establishing a healthy soil biology that are 100% devoted to being your plants' care takers, 24 hours a day 7 days a week, because the plant in turn provides them sugars created during photosynthesis, and supplied to them through the root system. It is this very powerful balance that allows nature to do so well in native prairies and forest with out our help. By recreating that system that is destroyed by construction, chemicals, over watering and other man made disturbances we can reduce our watering, and allow the soil to care for the plant the way it has been done for millions of years.

Category: Monthly Entries  |  Comments (0)

Join our Organic Blog

login   |   register

About this blog

Welcome! Soils Alive's blog was conceived as a method for Soils Alive to provide the latest and most up-to-date information for those who are curious or are seeking answers to common Organic Lawn Care issues.

Within this blog you will find anecdotes, issues and answers from Soils Alive's founder, Michael Bosco. Please comment on any entry or ask an organic lawn & landscape care related question.