Nutrient deficiencies

Learn what calcium does for cannabis plants, where to get it from amendments, supplements and nutrient solutions, and how pH affects calcium uptake.

Dark leaves or slow growth? Learn how to tell a low phosphorus feed from an uptake problem in cannabis, check pH and roots first, and correct it the right way.

Interveinal yellowing on older leaves? Check pH and roots first, then learn how to confirm magnesium deficiency in cannabis and correct it without overdoing it.

Spot calcium deficiency in cannabis, check pH and roots first, and correct a real shortage with the right calcium source without overfeeding.

Spot nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese, and zinc deficiencies by leaf symptoms.

A cannabis zinc deficiency shows up on the youngest growth first. Iowa State Extension lists the classic signs on young