Madeline Wimmer, UMN Extension Educator- Fruit Production & Soon Li Teh, Extension Specialist and Assistant Professor in Grape Breeding and Enology Image: a plant nutritional pyramid showing from bottom to top those nutrients supplied by air and water: Carbon (C), Hydrogen (H), and Oxygen (O); primary macronutrients: Nitrogen (N), Phosphorous (P), and Potassium (K); secondary macronutrients: Calcium (Ca), Magnesium (Mg), and Sulfur (S); micronutrients: Molybdenum (Mo), Boron (B), Nickel (Ni), Copper (Cu), Zinc (Zn), Iron (Fe), Chlorine (Cl), and Manganese (Mn). Graphic created by Madeline Wimmer, 2023. Plant nutritional analysis—also known as foliar/leaf/petiole testing—is the practice of analyzing nutrition within a plant to determine adequate, excess, or deficient nutrient levels. Oftentimes, this involves collecting a plant’s leaf, leaf with petiole, or only the petiole at a specific growth stage. Plant nutritional analysis is a critical step in determining any potential nutrie