Manganese is a micro-nutrient found in the soil. Symptoms of a plant suffering a deficiency of manganese sulfate include chlorosis, which is a yellowing of the leaves between the veins. This gives the leaves a marbled, pinstriped or checkered appearance, depending on the leaf structure of the individual plant affected. Ferrous deficiency may also cause similar symptoms, and often goes hand in hand with a manganese deficiency.
While most garden soils are not usually deficient in manganese, the acidity of the soil dictates how readily it is released and able for absorption by plants. Adjusting soil pH is often the first step in solving the problem. Acidic soils release manganese to plants more easily than do alkaline soils. The only way to determine the soil pH is to have it tested. Prepare a soil sample and send it off to your county extension office for testing.
Adjusting Soil pH
If your soil is too alkaline, increase its acidity by using conifer mulch or adding aluminum sulfate or sulfur to your garden. Acidic soils are adjusted by the introduction of dehydrated lime. Any of these treatments may be spread on the soil around the base of the plant.
Potted plants are much more prone to manganese deficiency than are garden plants, as frequent watering flushes micronutrients from the soil. In a pot or container, manganese cannot naturally reoccur, so must be added back in.
To correct manganese deficiency it is common practice to mix manganese sulfate or manganese oxide with a wetting agent, usually a fertilizer, and to either spray the deficient plants or apply in a band, or strip, alongside the affected plants. Manganese sulfate is more soluble than the oxide, and therefore performs better.