Bulletin #1089, Essential Potato Plant Nutrients

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Bulletin #1089, Essential Potato Plant Nutrients

By Steven B. Johnson, Ph.D., Extension Crops Specialist, University of Maine Cooperative Extension

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Potatoes require sixteen essential nutrients to produce an economically viable crop. Most of these nutrients are available from the soil. When soil-available quantities are not adequate for production goals, fertilizers are applied to compensate for these deficiencies. Fertilizer can also be applied to supply nutrients that are not available in the soil.

Nutrient Element Plant-Available Forms Common Forms in Soils
Nitrogen (N) NO3, NH4+ Organic, NH4, NO3
Phosphorus (P) H2PO4, HPO4-2 Organic, mineral
Potassium (K) K+ Mineral, exchangeable
Calcium (Ca) Ca+2 Mineral, exchangeable
Magnesium (Mg) Mg+2 Mineral, exchangeable
Boron (B) H3BO3 Mineral, organic
Chlorine (Cl) Cl Mineral, soluble
Copper (Cu) Cu+2 Mineral
Iron (Fe) Fe+2 Mineral, exchangeable
Manganese (Mn) Mn+2 Mineral, exchangeable
Molybdenum (Mo) MoO4-2 Mineral
Sulfur (S) SO4-2 Organic, mineral
Zinc (Zn) Zn+2 Mineral, exchangeable
Carbon (C) CO2 Carbon Dioxide
Hydrogen (H) H2O and others Water, H3O+
Oxygen (O) O2, H2O Oxygen, H2O

Nutrient Mobility

Within the soil solution, NO3, SO4-2, H3BO3, Cl, and MoO4-2 are mobile and move relatively freely with the soil solution. The other nutrients are immobile in the soil, do not move freely, and may be unavailable for plant uptake.

Within the plant, NO3, H2PO4, K+, Mg+2, Cl, and SO4-2 are mobile and are relocated within the plant. The other nutrients are immobile in the plant and are not relocated.

Nutrient Function in Potato Plants


Nitrogen is a component of amino acids, proteins, enzymes, nucleic acids, and chlorophyll, among other compounds in plants. Nitrogen is necessary for photosynthesis, respiration, and cell division.


Phosphorus is a component in nucleic acids, membranes, and ATP and ADP, which are used in energy transfer. Phosphorus is necessary for reproduction, respiration, and energy transfer.


Potassium is present as an ion (a charged particle) and is critical in opening and closing stomata, which allow carbon dioxide into the plant and oxygen out, and help regulate water flow within the plant. Potassium also plays a key role as a cofactor in enzyme reactions.


Calcium is vital in structural integrity of cell walls. Calcium is also needed for proper meristematic development.


Magnesium is needed for the chlorophyll molecule, which is essential for photosynthesis and respiration.


Boron is involved in cell elongation, cell walls, and movement of sugars from the leaves to the roots.


Chlorine maintains ionic balance in the plant, helps with membrane transport, and is essential in photosynthesis.


Copper is important for some chemical reactions and electron transport.


Iron is important for some chemical reactions, electron transport, and chlorophyll synthesis.


Manganese is essential in respiration and photosynthesis.


Molybdenum is needed for nitrogen-related enzymes.


Sulfur is essential for some amino acids and helps with protein structure.


Zinc is needed for some enzymes and for growth.

Information in this publication is provided purely for educational purposes. No responsibility is assumed for any problems associated with the use of products or services mentioned. No endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.

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