Staff — June 16, 2015
The plants you cultivate need more than sun and water to thrive. In addition to tender loving care, they need macro- and micronutrients provided in the proper balance. These nutrients occur naturally in soil, but in varying amounts and, in some cases, in varying quality. The appropriate, supplemental application of essential nutrients depends upon what’s present in the soil – and what a particular plant requires.
There generally are two types of nutrients: macro- and micronutrients. Put simply, those considered macronutrients are the elements that plants require in greater quantities than the micronutrients, which, as logic would have it, are those that are required in lesser amounts.
It all seems obvious, but this is why soil testing is critical to determining what’s sufficient, what’s lacking and what needs to be added.
Listed here are the nutrients, along with their basic characteristics or qualities, and general signs of deficiency. This is not intended to be a comprehensive analysis of the nutrients or their effects, but a simple guide to give plant professionals a starting point for further investigation. Soil tests conducted by reliable and reputable labs should be completed prior to application of supplemental nutrients; diagnosis of deficiencies should be confirmed as well. Overapplication of supplemental nutrients can be just as detrimental to plants as deficiency.
Macronutrients
Nitrogen (N), phosphorus (P) and potassium (K) are considered the “primary” nutrients. “Secondary” macronutrients are calcium (Ca), magnesium (Mg) and sulfur (S). Macronutrients are necessary for healthy growth and sustained vigor, but they must be balanced correctly.
The other essentials
We don’t often think of oxygen and moisture as “nutrients.” Without them, of course, plants wouldn’t survive. Structural, or nonmineral, nutrients – carbon (C), hydrogen (H) and oxygen (O) – are obtained from air and water. Each is necessary for the plant to convert into carbohydrates (sugars and starches), which help to build strength in cell walls and to support stems and leaves. Think of these as the most basic plant food.
Micronutrients
Considered “minor” or trace elements, micronutrients include boron (B), chloride (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn). Many support the functions of macronutrients
This is not intended to be a comprehensive analysis of the nutrients or their effects, but a simple guide to give plant professionals a starting point for further investigation. Soil tests conducted by reliable and reputable labs should be completed prior to application of supplemental nutrients; diagnosis of deficiencies should be confirmed as well. Overapplication of supplemental nutrients can be just as detrimental to plants as deficiency.
Nitrogen
- Essential for plant growth; part of every living cell
- Necessary for chlorophyll synthesis
- Directly responsible for increasing protein content in plants
- Must be present in sufficient amounts to facilitate nutrient uptake
Signs of deficiency:
- Plant is pale green
- Lower leaves may appear yellow to brown
- Symptoms appear first on older leaves, but may then spread throughout the plant
Phosphorus
- Captures and converts sunlight into essential plant compounds
- Stimulates root development
- Promotes improved flower and seed production
- Promotes increased stalk and stem strength
Signs of deficiency:
- Plant may appear dark green, with purple or red hues
- Lower leaves may appear yellow to dark green
- Symptoms appear first on older leaves, but may then spread
throughout the plant
Potassium
- Enhances enzyme actions, aiding in photosynthesis
- Maintains turgor, reduces water loss
- Increases root growth, improves drought tolerance
- Known as “quality nutrient” for overall effects on general plant quality
Signs of deficiency:
- Leaves appear wilted or scorched
- Edges or spots on leaf are necrotic
- Symptoms appear only on olderleaves
Magnesium
- Captures sun’s energy, facilitating photosynthesis
- Carries phosphorus; is required for better root formation
- Mobile within plant; moving from older to younger tissues
Signs of deficiency:
- Leaf edges appear yellow, but remainder is green
- Symptoms appear only on older leaves
Calcium
- Stimulates root and leaf development
- Affects uptake and activity of other nutrients
- Helps form compounds that compose cell walls, strengthening plant structure
- Balances organic acids; activates plant enzyme systems
Signs of deficiency:
- New leaves appear deformed
- Left edges and tips are necrotic
- Terminal bud appears healthy
- Symptoms appear first on young leaves
Sulfur
- Critical for photosynthesis and winter hardiness
- Appears in every cell; required for synthesis of amino acids and proteins
- Aids in seed production
- Aids in efficient nitrogen fixation in leguminous plants
Signs of deficiency:
- Entire leaf appears yellow
- Yellow coloration may spread toentire plant
- Symptoms appear first on young leaves
Boron
- Helps to improve seed set
- Is a component of cell walls
Signs of deficiency:
- Terminal bud dies
- Leaves appear deformed and/or necrotic
- Symptoms appear first on young leaves
Chloride
- Supports transport of macronutrients throughout plant
- Helps plant acclimate to varying water quantities
Signs of deficiency:
- White, necrotic spots may appear along leaf edges
- Leaf tips may curl or wilt
- Symptoms appear first on young leaves
Copper
- Least mobile of micronutrients
- Necessary for successful chlorophyll formation
Signs of deficiency:
- Plant growth appears stunted
- Leaves discolored, small and deformed
- Terminal bud appears healthy
- Symptoms appear first on young leaves
Iron
- Assists in chlorophyll formation
- Deficiencies display as chlorosis in leaves
Signs of deficiency:
- Yellowing between leaf veins
- Stems do not appear shortened or rosetted
- Leaves do not develop necrotic spots
- Symptoms appear first on young leaves
Manganese
- Assists in chlorophyll synthesis
- Accelerates germination and maturity
Signs of deficiency:
- Yellowing between leaf veins
- Stems appear shortened or rosetted
- Leaves develop necrotic spots
- Symptoms appear first on young leaves
Molybdenum
- Aids in the use of nitrogen
- Helps convert inorganic phosphorus to organic forms
Signs of deficiency:
- Mottling and interveinal chlorosis
- Plant may show overall chlorosis
- Leaves may curl or cup
Zinc
- Essential for several metabolic reactions, critical to early growth stages
- Aids in protein synthesis and growth regulation
Signs of deficiency:
- Yellowing between leaf veins
- Stems appear shortened or rosette
- Symptoms appear first on young leaves