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Plant Food Basics

Understanding Plant Nutrition

Nineteen elements are considered essential for plant growth. Carbon, hydrogen, and oxygen are primarily supplied by air and water. Plant roots absorb the remaining 16 elements from the surrounding soil. These elements are divided into three groups based on their relative abundance in plants: Primary Nutrients (or Major Nutrients), Secondary Nutrients (or Minor Nutrients), and Trace Nutrients (or Micronutrients). Although the Major Nutrients are needed in the greatest quantities, a deficiency of any one nutrient can prevent plant growth, or reduce it to unsatisfactory levels. Even though some soils may already contain these nutrients, they may not be in a form available for plant growth. The best way to ensure that all of the nutrients are available in the soil is through regular applications of plant foods.

The table below provides more information on each nutrient, its deficiency symptoms, and possible plant foods to cure the deficiency.

Function DeficiencySymptoms *Solutions
Nitrogen Vigorous growth & dark green color Light green leaves; stunted growth
Dried Blood, Garden
Manure, Cottonseed Meal, Urea
Phosporus Root development &
Smaller yields of seeds &
fruit; purplish leaves, stems & branches;
Rock Phosphate, Bone
Meal, Single Super
Phosphate, Triple Super
Potassium Overall hardiness &
disease resistance
Reduced yields; Spotted or curled leaves; Weak root system Muriate of Potash,
Function Deficiency Symptoms *Solutions
Calcium Plant vigor; Aids in
uptake of nutrients
Deformed terminal leaves; Poor root growth Garden Lime, Garden
Magnesium Essential part of
Yellowing of older leaves Garden Lime
Sulfur Dark green color;
Seed production
Yellow leaves; Stunted,
spindly plants
Garden Sulfur, Gypsum
Function Deficiency Symptoms  
Boron Increases flowering
& fruit development
Terminal buds die; Less
flowers & fruit develop
Garden Manure, Bone Meal
Chlorine Helps control water loss & moisture stress Plants wilt; yellow leaves Garden Manure, Greensand
Cobalt Improves growth &
Reduced growth and
yellowing of foliage
Greensand, Kelp, Cottonseed Meal
Copper Helps produce chlorophyll Yellow, wilted leaves;
Lack of flowering
Garden Manure,
Iron Promotes dark green
Yellow leaves Greensand, Garden
Manure, Cottonseed Meal
Manganese Helps produce chlorophyll Intervenous chlorosis in
younger leaves
Garden Manure, Greensand
Molybdenum Essential in some enzyme systems Pale green, rolled or cupped leaves Greensand, Lime (makes
it more available)
Nickel Enzyme Producton Yellow Leaves Greensand
Sodium Aids water regulation & photosynthesis Plants wilt Kelp, Garden Manure,
Bone Meal, Greensand
Zinc Enzyme & growth
hormone production
Yellow leaves, Rosetted
(clustered) leaves
Garden Manure, Greensand, Cottonseed

© 2014, The Espoma Company.