Master Gardener Practice Exam 2026 – Complete Preparation Guide

Nitrogen is the nutrient most directly tied to leafy, green growth because it’s a key part of chlorophyll, the pigment that powers photosynthesis, and of amino acids and proteins that build leaf tissue. When nitrogen is available, plants produce lush, vigorous foliage and deep green leaves. If nitrogen becomes deficient, you typically see older leaves pale and the plant’s overall growth slows, since nitrogen is mobile and moves from older leaves to newer growth as needed. In contrast, phosphorus focuses on energy transfer and root development, while potassium helps with overall vigor and water regulation, not the green leaf growth itself. Calcium strengthens cell walls and is important for growing tissues, but it doesn’t promote the rapid leaf production and chlorophyll concentration that nitrogen does.