For more than 30 years, Dr. Royal Heins of Oro Farms has devoted his career to unlocking the mysteries of plant physiology and applying those findings to benefit growers and the industry at large commercially. The work he and his colleagues and graduate students did at Michigan State University (MSU) was truly applied research growers would derive a direct benefit from in a relatively short period of time. Their findings helped growers reduce costs while increasing quality and consistency.
But perhaps his greatest legacy is the next generation of scientists leading floriculture research today, many of whom earned their doctorates at MSU. Heins retired young and has spent the last six years as president of Guatemalan cuttings producer Oro Farms. He also remains one of the most in-demand consultants advising growers today. We asked him to reflect on how far growers have come in production and how far they still need to go to perfect their crops.
GG: What are the most significant strides growers have made in programming plant production in the last 20 years?
RH: I believe there is a much better understanding by growers of the environmental factors controlling flower induction and subsequent development. And with this understanding has come a much better management of these factors.
GG: What do growers still need to learn? Are there problems you see that are solved, but are still occurring because the solutions have not been adopted widely?
RH: I believe the two biggest misunderstandings in crop production relate to nutrition. There is a strong belief that ammonium is responsible for “stretch” in plants when data from Dr. Paul Nelson and his team have clearly shown that phosphorous is the major nutrient responsible for affecting stem elongation in plants. The misunderstanding is related to the coupling of percent ammonium with percent phosphorous in pre-mixed fertilizers.
Switching from a fertilizer low in ammonium to one higher in ammonium is almost always associated with an increase in phosphorous, and the typically observed increase in stem elongation is correlated by the grower with the increase in ammonium, not the increase in phosphorous. Correlation does not necessarily mean causation. We as humans must be careful to separate correlation from causation with good data.
The second misunderstanding is the amount of nitrogen fertilizer required to produce a plant. It is rare to find a nutrient recommendation in grower literature recommending less than 200 ppm nitrogen. I do not know of a single plant that will utilize 200 ppm nitrogen when it is applied at every irrigation. Feed, feed, leach. How often do we still see this nutrient strategy? Our industry wastes truckloads of fertilizer each year following this approach. In my experience, constant fertilization with 100 to 125 ppm nitrogen and 12 to 15 ppm phosphorus is adequate and appropriate to grow most finish crops.
GG: When it comes to production, what takes a grower from good to great?
RH: Dr. Will Carlson, whom I was privileged to work with for many years while at MSU, shared more than once, “Do what needs to be done when it needs to be done.” It really is that simple. For the most part, growers know what needs to be done. Getting it done, especially the simple things (transplanting, spacing, pinching, growth regulators, etc.) when it needs to be done is the factor that I see that takes one from good to great.
GG: How well do growers understand the power and influence of manipulating light and temperature?
RH: Overall I would say growers have a good understanding but sometimes proper manipulation could be applied better or earlier. One recent and exciting trend in research is directed toward a better understanding how these factors relate to timing of the crop. I have seen many growers use cool growing strategies as a means of saving money.
Work by Dr. Erik Runkle and Dr. Jonathan Frantz has shown that by growing with warmer temperatures in the spring, and therefore finishing the crop in a shorter time, one actually saves money on that crop’s energy costs. Conversely in the fall, work by Dr. Jim Faust has demonstrated that by selecting quick finishing poinsettia varieties one can reduce temperatures during the coldest part of the poinsettia season and save energy costs on the crop.
GG: How widely used is DIF (mathematical difference between day and night temperatures)?
RH: I see the DIF concept used frequently, both to limit elongation as well as promote elongation when needed. Negative DIF tends to be greater in more northern locations where temperatures allow it to be used more often. DIF does not just mean negative DIF or warm nights/cool days. If you have short plants Positive DIF (warm days/cooler nights) is a tool to promote elongation.
GG: Has there been anything new you’ve been doing with growers to enhance the performance and handling of cuttings, plugs and liners?
RH: There are three management strategies that have worked well to improve young plants. First, for cuttings is the use of a growth retardant application one to three days from stick. Early growth regulator applications promote compact mother shoots allowing for multiple nodes and lateral shoots at time of pinching.
Second, application of a growth retardant drench just prior to transplant is especially useful in controlling aggressive plants that are planted into a combination container with plants that are less aggressive.
Third, for photoperiodic plants is the management of photoperiod to delay flower induction early in the plug or liner followed by photoperiod management late in the life of the plug or liner to promote flowering, so plant sizing and crop timing is synchronized.
GG: Anything else you’d like to say about the future of plant production?
RH: I would encourage all growers to invest in financial support of the faculty at the university of their choice to further knowledge for themselves, as well as our industry as a whole. Consider it an investment, not an expense. It will pay off.