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The Effects of Nutrients on Plant Growth

I. Primary Plant Nutrients:

A. Nitrogen (N)

  1. Gives dark green color to plants
  2. Promotes rapid growth
  3. Feeds soil microorganisms during their decomposition of low-nitrogen organic materials
  4. If supply out of balance with that of other nutrients, may delay flowering and fruiting

B. Phosphorus (P) – In fertilizer stated as Available Phosphate

  1. Stimulates early root formation and growth
  2. Gives rapid and vigorous start to plants
  3. Stimulates blooming and aids in seed formation

C. Potassium (K) – in fertilizer stated as Potash (K2O)

  1. Imparts increased vigor and disease resistance to plants
  2. Stiffens stems
  3. Essential to the formation and translocation of tarches, sugars and oils
  4. Improves quality of fruit

II. Secondary Plant Nutrients:

A. Calcium (Ca)

  1. Promotes early root hair formation and growth
  2. Improves general plant vigor and stiffness of stems
  3. Facilitates improvement in soil structure
  4. In certain forms, raises ph

B. Magnesium (Mg)

  1. Is an essential part of chlorophyll
  2. In certain forms, raises ph

C. Sulfur (S)

  1. Helps maintain dark green color
  2. In certain forms. Lowers ph

III. Micronutrients:

A. Iron (Fe)

  1. Associated with production of green chlorophyll

B. Boron (B)

  1. Increase yield or improves quality of fruit and vegetables

C. Manganese (Mn)

  1. Accelerates germination and maturation
  2. Increases availability of calcium, magnesium and phosphorus
  3. Aids in the synthesis of chlorophyll and functions in photosynthesis

Plant Nutrient Deficiency Symptoms

Nitrogen: Light green or yellow-green color. The older leaves are paler than the new leaves. Drying up or “firing” of leaves which starts at the bottom of the plant, proceeding upward. In Plants like grasses, the firing starts at the tips of the bottom leaves and proceeds down the center or along the midrib. A distinctly slow and dwarfed growth.

Phosphorus: Plants small, very dark green, sometimes bluish-green and may show an abnormal amount of red or purplish-red pigmentation. Slow growth and maturity.

Potassium: Yellow streaking, mottling, spotting, or curling of older leaves, usually leaving a green midrib, followed by browning and drying at the tips and margin. The dead areas may fall out, leaving ragged edges.

Calcium: Reddish brown between veins along younger leaf margins. Young leaves in terminal bud become “hooked” in appearance and die lack at the tip and along margin. Leaves have wrinkled appearance and in some cases young leaves remain folded.

Magnesium: Light green, yellow-green streaks changing to cherry red, which starts with the bottom leaves and later moves up the stalk. The veins of the leaf remain green. Leaves curl upward along the margin.

Sulfur: Young leaves, light green in color, have even lighter veins. Gradual firing starting at the leaf tip. Short, slender stalks, yellow in color, slow stunted growth.

Iron: Chlorosis or yellowing between the leaf veins, which remain green.

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