As the vast and well catalogued world of plant nutrition research begins to intersect with the nascent cannabis industry, commercial growers are increasingly turning toward established companies with experience in nurturing healthy crops on a large scale. Harrell’s, which was founded in 1941 in Lakeland, Fla., now offers a tailor-made solution for growers interested in increasing yield and carefully tending to the nuances of their cannabis plants.

Dr. Raymond Snyder, Harrell’s Director of Agronomy, says that close observation is required: both in how Harrell’s formulated its plant nutrition products and in how growers implement them. His company is committed to that careful examination with its customized Harrell’s MAX Rx program.

“These offerings in the cannabis market are the evolution of what we intended to start 12 years ago,” Snyder said. “The overarching goal was to have products that are clean, clear and compatible. We could mix our individual components with one another and that would result in a stable solution that did not have any compatibility issues over time and that would have maximum plant performance and efficacy.”

The program comes from tropical plant and soil expert Lynn Griffith, who traveled the world to learn more about cannabis’ unique history and climatic needs. From there, he worked with Harrell’s to reproduce a line of nutrients that gives cannabis its best chance for success.

“Some of the core properties of the program include: optimized amounts of nitrogen, calcium, magnesium, boron and iron; fertilization within soluble salt limits; amino acids; vitamins; hormones; silicate and phosphorus,” Snyder says. “We stressed using only the highest-solubility, lowest-impurity raw materials.”

This is key. High solubility leads to minimal precipitation or “fall-out”—sediment, in other words, that’s separated and gathered at the bottom of a batch of formula.

“Having a material that is highly soluble helps with overall plant uptake, minimizes the impurities that may be part of a raw material that would have fall-out in the solution,” Snyder says. “Anytime you have impurities in your solution, that’s just less AI, if you will, less potential for that desired component—whether that’s nitrogen, phosphorus or potassium—to get into the plant. It lends itself to more efficiency of the solution and greater uptake potential. Those impurities impact antagonism with other elements when you’re trying to create a final solution.”

The MAX Rx program is built to accommodate growers’ individual needs, but, by and large, it’s been developed with straightforward plant health in mind. Griffith has said that his work on the program comes from his laboratory experience and extended research on cannabis soils.

When the program is deployed, however, it’s up to the grower to continue observation of the crop.

“If I’m a grower, I’m looking at the characteristics of the products in their stock tanks,” Snyder says. “Are they maintaining their color? Their integrity, minimal or zero precipitation or fallout of the desired plant nutrients. That’s where it starts, in terms of overall quality of a solution. I’m monitoring the plant response, the growth response, overall vigor, rigidity of the plants as these inputs are imparted into the nutrient stream. Consistent growth, not peak-and-valley-type growth.”

That consistency comes through the spectrum of raw materials that Harrell’s brings to the MAX Rx program. Potassium silicate helps with the stoutness of leaves and bud density, for one example, translating to higher yields. The program can generate up to 30- or 40-percent yield increases, with a reported average of 14-percent yield increase. This is due to the broad spectrum of effects that the Harrell’s MAX Rx program elicits: compact plant growth along shorter internodes brings about a more robust flowering phase.

The program follows standard growth phases: propagation, veg, early bloom and late bloom. Throughout each phase, different levels of core nutrients—nitrogen, calcium, magnesium, boron, iron and others—are applied. Magnesium, for another example, is a critical ingredient in forming the stout, dark-green leaves that convey good health.

A stand-out component that appears throughout the growth process is seaweed extract. Cannabis is receptive to the amino acids in seaweed products—something that Griffith discovered in the research around the MAX Rx program.

“We did a lot of research in terms of attempting to identify the best seaweed source,” Snyder says. “There are several different seaweed extract sources. There are also different ways of processing these various seaweed raw materials. The source that is most supported by the academic world is the form of seaweed known as Ascophyllum nodosum.”

Research, indeed, is built into every step of the MAX Rx program.

Snyder says, after all, that there’s value in a grower having the access to a nuanced pre-mix that allows him or her to free up time devoted to the plant itself.