Identifying signs of nutrient deficiency in vegetables can be confusing, as many plants exhibit similar symptoms. When vegetables lack essential nutrients, they appear unhealthy and may even die. Symptoms range from yellowing and poor growth to flower and fruit failure, making it crucial to recognize and address these deficiencies.
Vegetables, like other plants, obtain their nutrients from the soil, and their availability can be determined through a soil test. This test will guide you in correcting any deficiencies.
Read also: Essential Plant Nutrients Deficiency and Toxicity Symptoms
Now, let us look at the vegetable nutrient deficiency symptoms, nutrient source and toxicity symptoms.
1. Nitrogen (N)
Function: It is necessary for green, leafy growth and the formation of chlorophyll necessary for photosynthesis. It also forms part of the protein.
Sign of nutrient deficiency: Leaves appear pale green or bluish then turn yellow (chlorosis). Leaves drop, the oldest leaves fall first, with small leaves, thin stems, low vigour of plants and stunted growth.
Sign of excess: Dark green leaves, excessive leaf growth instead of buds and fruits.
Source: Manure, bonemeal, blood meal (dried blood), fish meal, fish emulsion (also contains phosphorus and potassium, in small amounts), cottonseed meal (also contains small amounts of phosphorus and even smaller amounts of potassium), coffee grounds (also contains minimal amounts of phosphorus and potassium), soybean meal (also contains small amount of potassium and even smaller amount of phosphorus), composted legumes (peas, beans, peanuts), ammonium sulfate or nitrate.
Read also: Essential Plant Nutrients, their Functions and Nutrient Sources
2. Phosphorus (P)
Function: Essential to photosynthesis, strong growth, bloom and good root development, cell wall structure development and moisture conservation, all necessary for photosynthesis.
Signs of nutrient deficiency: Lower leaves and stem look reddish or purplish, young leaves look pale, shoots are thin, plants do not flower or form fruits, premature fruit drop, stunted roots and slow cell division.
Sign of excess: Essential elements may be tied up.
Sources: Bonemeal, colloidal phosphate, rock phosphate (contains slightly more phosphorus than colloidal phosphate, breaks down more slowly), superphosphate.
3. Potassium (K)
Function: Promotes disease resistance, necessary for root development and cell wall structure development, good for moisture conservation and promoting photosynthesis.
Signs of nutrient deficiency: Lower spotted, mottled or curled leaves. Leaf tips and edges turn yellow and bronze, then brown and appear dry, with weak stems, a small root system, and reduced plant vigour. Moreover, plants are susceptible to wilting and wilt diseases, it develops small fruits, thin-skinned fruits, and fruit with poor colour and flavour.
Sign of excess: Fruits are coarse and poorly coloured and there is reduced absorption of magnesium and calcium.
Sources: Potash rock, manure, granite dust or meal (also contains trace elements), greensand (also contains trace elements), New Jersey greensand, fish meal, seaweed, kelp meal (also contains small amounts of nitrogen, smaller amounts of phosphorus and trace elements) wood ashes (also contains some phosphorous, raises soil pH), potassium sulfate or nitrate.
4. Calcium (Ca)
Function: Promotes cell division, building plant proteins, flowering and fruiting.
Signs of nutrient deficiency: The growing tip of the plant is damaged or dies back. Tips of new leaves are yellow and appear scorched. Young leaves and buds die back. Weak stems, blossom-end rots of fruit, cavities in tomatoes, black heart and black roots.
Sign of excess: Reduced intake of potassium and magnesium.
Sources: Calcitic limestone, dolomitic limestone, gypsum, eggshells, oyster shells, fish meal, wood ashes, slag.
5. Magnesium (Mg)
Function: Plant strength.
Signs of nutrient deficiency: Lower leaves and older leaves mottled–yellow and white patches between green veins of leaves; brownish or purplish patches may form on leaves; old leaves white or yellow; leaves fall prematurely; growth is stunted; poor flower and fruit quality.
Sign of excess: Absorption of calcium and potassium is reduced.
Sources: Dolomitic limestone, manure, New Jersey greensand, talc, magnesium sulfate (Epsom salts), green plants.
6. Sulfur (S)
Function: For healthy growth.
Signs of nutrient deficiency: Deficiency is rare. Young leaves are pale green to yellow with stunted growth of the plant.
Sign of excess: Sulfur burn from too low pH.
Sources: Gypsum, composted legumes, composted cabbage leaves; sulfur, superphosphate.
Read also: Vermiculture and Vermicomposting: Benefits and Constraints In Organic Farming
7. Boron (B)
Function: Important to plant growth.
Signs of nutrient deficiency: Young leaves are pale green at the base, develop yellow spots, become twisted, thickened and curl under. It develops small leaves, multiple buds, dieback from terminal buds, heart rot (corkiness), internal cork of apples, cracked stem in celery, heart rot and girdle of beets.
Sign of excess: Leaves turn yellowish red.
Sources: Clover, composted melon plants, borax (add only if prescribed), granite dust.
8. Copper (Cu)
Function: For plant growth and helps the utilization of iron.
Sign of deficiency: Young leaves turn pale and may become mottled and wilt. The leaves develop brown spots, leaf tips dieback, leaves may not grow, growth slows or stops, multiple buds, gum pockets, lack of leaf development in citrus.
Read also: Site Selection for Farming Purposes: 7 Very Key Factors to Consider
Sign of excess: Iron uptake blocked.
Sources: Manure, rock powders, copper sulfate (use with care), neutral copper, composted dandelions, grass clippings, and sawdust.
9. Iron (Fe)
Function: Plant growth, chlorophyll and carbohydrate production.
Signs of nutrient deficiency: Young leaves turn yellow or very pale but veins remain green (chlorosis); growth is weakened and stunted.
Sign of excess: None known.
Sources: Humus, manure, compost, blood meal, New Jersey greensand; chelated iron, iron sulfate (copperas).
10. Manganese (Mn)
Function: Growth and plant maturation.
Signs of nutrient deficiency: Leaves mottled yellow and white. Brown spots may develop on leaves. Stunted plant growth or plant slow to mature.
Sign of excess: Tissue dieback in the leaves, dieback surrounded by yellow border.
Sources: Oak leaves, leaf mould, carrot tops, alfalfa, manganese sulfate.
Read also: Types of Inorganic Fertilizers and Their Characteristics
11. Molybdenum (Mo)
Function: Essential for converting nitrates into amino acids and conversion of phosphorus into plant forms.
Signs of nutrient deficiency: Leaves turn yellow and pale between veins. Leaves may become bluish green and leaves do not open completely. Plant growth is stunted.
Sign of excess: Poisonous to livestock.
Sources: Sodium molybdate.
12. Zinc (Zn)
Function: Fruit development.
Signs of nutrient deficiency: Young leaves mottled yellow, plant tips stop growing. Plants wilt easily. In peat and alkaline soils, leaves are abnormally long, narrow and mottled. Yellowed leaves, poor fruiting, dieback. Deficiency leads to iron deficiency, which it resembles. Also, leaves are thickened and malformed, small and narrow. Growth is stunted.
Sign of excess: None known.
Sources: Manure, composted corn, ragweed, vetch; zinc sulfate.
Conclusion
Understanding and addressing nutrient deficiencies in vegetables is crucial for healthy plant growth and optimal yields. By recognizing symptoms and knowing the sources and effects of various nutrients, you can ensure your vegetables thrive.
Reference
Vegetable Plant Nutrients: Sources and Deficiencies (harvesttotable.com)
