Biostimulants are organic products that aid in plant metabolic processes such as respiration and photosynthesis. Bio-stimulants include natural-occurring ingredients such as plant hormones, carbohydrates, amino acids, and anti-oxidants.

Minnick blog on bionutrients

I was out in Dallas, TX to visit with some of the best field and grass guys I know.  And WOW the gorgeous bermudagrass that I got to see and the things I learned.  Thank you to all of them for their precious time!!

We will finish our discussion on growing strong, healthy and durable turfgrass today.  But obviously this isn’t the “end” of the discussion. It is only the beginning! With the need for increased revenues and the demand from so many user groups, high traffic athletic fields is the new challenge for us as field managers to meet… at all levels. Yes it means more challenges, but in the end I see it as a huge boost for our industry as we will step up and meet the challenge.

Thank You to everyone that has engaged me in conversation over these topics, WOW the good ideas that we have created! Today we build on nutrient management with a discussion about the success we have in utilizing bio-stimulants for natural growth and


To start, let’s establish what I mean when using the phrase “bio-stimulant”. Bio-stimulants are organic products that aid in plant metabolic processes such as respiration and photosynthesis.  Bio-stimulants include natural-occurring ingredients such as plant hormones, carbohydrates, amino acids, and anti-oxidants.

Plant Hormones: 
Plant hormones serve as “signaling molecules” for plant growth. They carry messages from one part of the plant to the other.  There are 5 growth hormones in turfgrass, but we primarily focus on 3:  auxins, cytokynins and gibberellins.

Auxins signal root growth and development, and work with cytokynins to initiate shoot growth.  Gibberellins help supply food for new cell growth and promotes cell division and elongation in the leaf blade of the grass plant.

With this understanding of plant hormones, the illustration of how we utilize them for natural and healthy plant growth becomes basic.  When root development and density is needed, auxins and cytokynins are applied to drive roots and shoots.  If recovery or grow-in is required, cytokynins and gibberellins are used to promote vertical growth through leaf elongation.  When used in proper balance, these three (five total) hormones work together with proper nutrient management to reach the end goal of creating a strong, healthy and durable grass plants.

Additional Benefits from Amino Acids/ Carbohydrates/ Anti-Oxidants
Bio-stimulants can also assist plants in dealing with heavy traffic and stress, in particular heat (summer stress) or low light (early and late season growth).  In times of stress, plant respiration is burning more energy than photosynthesis can produce.  The plant turns to its stored reserves (roots) to balance out the deficit of energy, leading to a weaker plant.  Bio-stimulants can assist the processes to lessen the demand on the plant roots for energy in route to creating a strong, healthy and durable plant- more naturally.

Growth Regulators become Growth Distributors
Continuing our discussion of the plant’s biological systems, we have also had tremendous success with using growth regulators as we strive to produce a strong, healthy and durable plant.

When I started using growth regulators, I had an extreme fear of them causing more damage than harm in a high traffic field situation.  What if I couldn’t get the field to grow at all?  Because of that fear, I started using trinexapac- ethyl (Primo) at ½ of the ½ rate.  (¼ of the recommended rate)

Curiosity exploded when even at that low rate, the density of the turfgrass stand increased.  Most evident was seeing the same amount of clipping yields in our baskets from mowing.  The clippings were coming from lateral growth from the increased density instead of from vertical growth though.

Since then, I have decided they we should no longer call them growth regulators…. They are instead growth distributors.  There is a negative connotation to growth regulator.  So now when I refer to “growth distributors”, we will feel positive about them!

With further exploration of growth distributors, we began using flurprimidol (Cutless).  Trinexapac-ethyl (Primo) is blocking the production of gibberellic acid late in its production cycle.  Cutless is blocking gibberellic acid early in its production.  What does that mean?  Well… to me it seems like if we block the GA earlier, we will actually have MORE energy to re-direct because the plant has used less energy to produce any GA.  So ultimately there is more energy to distribute to the rest of the plant.

Is that a scientific explanation? NO ha ha.  But it sure seems to make sense.

The results of using Cutless have been even more impressive than using Primo-  Wide, dense, and traffic tolerant leaf blades on all plants.  Our mowing has been reduced some as well, but not dramatically.  The density promoted when mowing between ¾” and 1 ¼” on Kentucky bluegrass and at ½” on bermudagrass still yields mowing clippings nearly every day.

With the use of bio-stimulants in conjunction with plant growth distributors, we feel like our program has control over plant growth processes throughout the year.  Different demands on fields (for example, youth soccer clinics vs. men’s lacrosse) and unpredictable weather conditions changes the needs of the turfgrass plant almost daily.  But using these products and monitoring the plant processes at all times sets the “diet” for maintained a strong, healthy and durable plant!!