Ferrous sulfate is used to treat plants and shrubs with what deficiency?

• A. Nitrogen deficiency
• B. Potassium deficiency
• C. Ferrous sulfate
• D. Phosphorus deficiency

Answer: (C)

Iron deficiency in plants shows as yellowing between the veins of new growth, a condition called iron chlorosis. Ferrous sulfate provides iron in a form plants can take up (Fe2+), making it an effective remedy for this deficiency when applied to soil or used as a foliar spray. The other nutrients—nitrogen, potassium, and phosphorus—cause different problems and require different amendments, so they aren’t addressed by ferrous sulfate. In alkaline soils, iron becomes less available, so supplying iron directly with ferrous sulfate helps correct the deficiency.