Monopotassium Phosphate — commonly known as MKP — is the sole phosphorus source in the PPS-Pro system. Phosphorus plays a critical role in root development, energy transfer within the plant, and the structural integrity of cell walls. Without it, plants struggle to establish themselves and growth becomes weak and slow.

You use far less phosphate than nitrogen or potassium, which is why the pack size is smaller. 50g is the standard amount for one full PPS-Pro macro mix. Phosphorus deficiency typically shows up as slow, stunted growth and reddish or purplish tints on older leaves — symptoms that are easy to prevent with consistent dosing.

MKP is highly soluble and mixes easily. It goes into the macro bottle alongside the other compounds.