You probably think you've covered all your bases: your NPK is on point, your pH is dialed in, and there isn't a pest in sight. Sounds good, but did you know that plants without Manganese can suffer? This important micronutrient plays a valuable role in photosynthesis and helps plants hold their own against environmental stresses. OMRI Listed® and Registered CDFA Organic Input Material. Prepare Your Plants To Perform!