Why Calcium is Important for Turf Growth
Sean Breckin, AOLCP

PJC Organic is proud to stay up to date on the best research available. We’re able to provide our customers with quality organic product recommendations and programs. We carefully evaluate field studies and look for best ways to implement and improve our current program offerings. Here, we give you our take on the scientific research behind productive turf grass and soil management. I dive into information gleaned from “The Albrecht Papers: Albrecht on Calcium – Volume 5” by William A. Albrecht to share why calcium is important for turf growth.

While the late Dr. William Albrecht’s research dates to the 1940s and 50s, his postulations on the importance of calcium applications to soil are very relevant to organic turf care.

pH & Calcium

PJC Organic identifies soil pH as the most critical element of soil chemistry. We point to a soil pH between 6.5 and 6.8 as optimal for growing turf grass. In addition, beyond the bioavailability of other plant essential nutrients, calcium itself is critical for: soil structure, plant nutrient assimilation, and plant structure. Highly acidic soils and highly alkaline soils lack available calcium ions. Acidic soils replace calcium with hydrogen ions, which lower pH (increase hydrogen concentration). Therefore lowering calcium saturation (both pH and base saturation in our soil tests reflect calcium availability). Alkaline soils bind calcium ions – most often due to compaction – and result in inaccurate soil test results for cation exchange capacity and base saturation. 

Albrecht considers calcium delivery as important as nitrogen, phosphorus, and potassium in common fertilizer applications. He states: “Calcium is effective in bringing higher concentrations of proteins and other essential nutrients within that bulk. According as the active calcium dominates the supplies of nutrients in the soil, so proteinaceousness – and with it a high content of growth minerals – characterize the vegetation produced on the soil.” (Albrecht on Calcium: Chapter 24 Pg 121)

Varying Levels of Calcium

Much of Albrecht’s research tested the importance of calcium by minimizing variables. He’d often deliver the exact same concentrations of N-P-K into soil media to test different growth rates of crops. What he overwhelmingly found was that offering different levels of calcium to the plants, their vegetative performance varied greatly. In instances where calcium was not administered, vegetative production suffered or worsened. On the other hand, in studies where calcium was administered, vegetative production and seed germination improved tremendously. 

Turf Application

While Albrecht’s quote above (ch. 24) is quite wordy, it captures the essence of his belief that calcium acts as a transporter of nutrients into the plant, while also maintaining an appropriate balance of nutrients in the soil. Applying calcitic lime or gypsum is not just a means to improving soil chemistry and structure. Calcium should also be considered a major plant food due to its ability to carry nutrients, proteins and carbohydrates into the plant. When developing organic turf care programs, oftentimes we find that looking into the past may be the best means to moving forward in the future.