Plant Nutrient Deficiencies

The striping on these corn leaves denote a deficiency in manganese due to drought. Photo Amanda Jarrett

Deficiency and Toxicity Symptoms of Plant Nutrients

iron deficiency, rhododendron, nutrient deficiencies, fertilizers, fertilizing, interveinal chlorosis

Symptoms of iron deficiency on a rhododendron are interveinal chlorosis.

There are many reasons why plants suffer from hunger, but basically it has to do with the type of soil, the condition of the soil, it's structure and what nutrients it holds. Nutrients are unavailable to plants because the soil pH is too high or too low. Sandy soils contain little nutrients and, they don't hold onto nutrients. Compacted soil deprive roots of water, air and nutrients. When roots cannot do their job properly due to incorrect soil conditions, it doesn’t take long for plants to show their displeasure. Plant hunger symptoms include yellow foliage, brown margins (leaf edges), purple tinted foliage and leaves with yellow between green veins. Plants also may bear distorted, twisted stunted leaves and stems and whole plants become tiny versions of themselves. Failure for plants to form fruits and if they do they are distorted, could be caused by nutrient deficiencies. Lack of flowering and too few foliage could also be due to lack of the appropriate nutrient.

Be careful when applying fertilizers, even organic ones. A sudden flood of nutrients plays havoc on the soil ecosystem, especially synthetic fertilizers. It's an easy way to harm all those beneficial soil micro-organisms and really screw up your soil. Plants suffer too with nutrient toxicities, it's a bit like plant overdosing. Follow manufacturer’s instructions with all plant foods, whether they are organic or not. Speaking of which, with the addition of compost added to soil on a yearly basis as well as a 3 inch layer of organic mulch, nutrient deficiencies and toxicities are not usually an issue.

Be Aware of Fresh Organics & Nitrogen Immobilization!
Adding non-aged, fresh manure, green grass clippings and other still green and fresh organic material to garden beds create nitrogen deficiencies. This is referred to as nitrogen immobilization. The soils' microorganisms use nitrogen as they feed on the non-decomposed organic debris, depriving plants of nitrogen. When this happens, use a liquid fertilizer high in nitrogen (the first number), such as a fish fertilizer. It will work fast to remedy the nutrient deficiency.

Nutrient Deficiencies & toxicities

Nitrogen Deficiency:

yellow or light green leaves
mature leaves a lighter green than new leaves
lower leaf tips turn brown
slow plant growth
stunted plant growth
lack of vigour
increased occurrence of diseases and insects

Nitrogen Toxicity:

soft, succulent, new growth easily damaged by frost
lacks flowers and fruit
excessive foliage, plants larger than normal
diseases and insects increased
leaf margins brown and crispy
wilting and death

Magnesium Deficiency:

older leaves yellow
the leaves are yellow with green veins (interveinal chlorosis)
early leaf drop in autumn
green ‘V’ shape at base of leaves
blueberries and other acid loving plants are prone when grown on alkaline soils

Manganese Deficiency:

leaves are yellow with green veins (interveinal chlorosis)
mottled foliage
yellowing leaves
on palms, new growth is frizzled and stunted (‘frizzletop’)

Zinc Deficiency:

small leaves, especially young ones
short internodes (leaves tightly spaced together)

Sulfur Deficiency:

plant is pale
veins slightly lighter than the leaf

Molybdenum Deficiency:

twisted, elongated leaves on broccoli and other brassicas
pale, stunted leaves
occurs when soil is too acidic

Copper Toxicity:

white between green veins on mature foliage
stunted growth
occurs when using sewage sludge fertilizer

Phosphorus Deficiency:

stunted growth
weak roots
delayed maturity
few flowers, fruit and seeds
purple foliage that turns yellow with age

Potassium Deficiency:

outer edges or tips of lower leaves are scorched or burned
leaf edges brown
poor flowering and fruiting
increased incidence of disease
slow growth
fruit is shriveled
leaves tend to cup downwards

Calcium Deficiency:

plant tips die
brown leaf edges
rapid death
often a problem with container grown tomato plants

Iron Deficiency:

young leaves are yellow with green veins (interveinal chlorosis)
leaf tips and stem tips brown and die
lack of vigor and growth
blueberries and other acid loving plants are prone when grown on alkaline soils (and heavy doses of lime)

Boron Deficiency: