Nutrient Toxicity – Over supply of Nutrients and its impact!

Signs to watch for nutrient toxicity

If insufficiency of element content can cause malnutrition/deficiency, so also excess of nutrition supplied can cause toxicity in plants!

This nutrient toxicity is likely to occur

  • When fertilizers are applied in excess than the recommended dosage.
  • Use of water with high micronutrient/salt levels.
  • Growing of plants in a region/soil, where the concentration of the element is high

What will happen if there is an excess concentration of elements? – Simply putĀ  -excess/toxicity of elements may cause reduced uptake of other elements.

Signs to watch for individual element toxicity:

Nitrogen (N)- plants with amounts of nitrogen turns dark green colour and contributes to delayed maturity (due to prolonged vegetative growth stage) as nitrogen helps in promoting the vegetative growth of a plant

Higher concentrations of nitrogen lead to quick and luxury growth in plants finally producing tall and weak plants

Phosphorous (P)– Excess of phosphorus levels indirectly effect on plant growth by reducing the uptake of elements like iron, manganese and zinc and hence, causes these deficiencies in plants. In general, higher levels of P reduces Zinc uptake, and hence Zinc deficiency will be common

Potassium– higher amounts of potash influence on magnesium uptake and in some cases cause Calcium deficiency


The line of deficiency and toxicity of micronutrients for many plants and crops is narrow!

Boron is a typical example, where insufficiency range and toxicity range almost overlap each other.
None of this should dissuade you from trying to do your best to keep your plants supplied well with nutrition and sufficient water.


Enjoy your time with the plants and make the most of it!

Sushma completed her B. Sc. from College of Horticulture, Hiriyur and M. Sc. from College of Horticulture, Bengaluru. She is an avid gardener with expertise across soil based and soilless gardening techniques using substrates.

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