Deficiency of major nutrients

Deficiency of major nutrients

When major nutrients Nitrogen, Phosphorus, Potassium are deficient, yellowing first occur in older or matured leaves.  

Nitrogen Deficiency:

Symptoms:  general yellowing throughout the older leaves including  veins, leaf drop, premature flowering and fruiting.


  • Nitrogen is a very soluble and mobile element; it is easily leached into water ways and also easily lost to the atmosphere
  • This can result in deficiencies which can be identified as yellowing of matured leaves in spring & autumn growth.

    Remedy :

  • regular application of organic manures and also applying Nitrogen rich fertiliser such as Sulphate of Ammonia, and Urea
  • Organic, granular, tablet or soluble fertilisers containing NPK will also supply adequate levels of Nitrogen in soils if applied regularly.

 Phosphorous Deficiency:

Symptoms : poor growth, blue green to purple color look on leaves and stems (particularly underneath leaves). Deficiency is mainly noticed in older leaves.

Cause: Phosphorus is needed for healthy root and shoot growth. Low level of phosphorous in soils are not that widespread, however Australian soils do have a reputation for having lower than average levels of Phosphorous.  Low Phosphorous levels may occur in areas with high rainfall and in heavy clay soils.  Phosphorus deficiency also occurs in highly acidic soils.

Remedy : When soils are highly deficient in phosphorus apply  Phosphorous  rich fertilisers such as as Manutec  Super phosphate,  Manutec Blood and Bone, other regular application of fertilisers containing NPK with trace  elements  will be sufficient to maintain enough Phosphorus levels.

Potassium deficiency:


  • Initial symptoms include appear on leaves (older) with scorched  margins, spots surrounded by pale zones with yellow or purple tints with browning at the leaf edge
  • If enough Potassium is not supplied, finally results in poor flowering or fruiting, such as small size flowers, less number of flowers, pale color flowers & fruits etc.

Calcium Deficiency:

Symptoms : generally   necrotic leaf margins and curling of young leaves, death of terminal buds and root tips.

Crop-specific symptoms include :  In tomatoes and HPeppers H (Capsicums)  : ‘Blossom end rot’ – Symptoms start as sunken,  dry decaying areas at the blossom end of the fruit, furthest away from the stem, not all fruit on a truss is necessarily  affected. Sometimes in addition to calcium rapid growth from high-nitrogen fertilizers and irregular watering (over or under) may also cause blossom end rot.

  • In Apple – develop bitter pits –  fruit skins develop pits, brown spots appear on skin and/or in flesh and taste of those areas is bitter.
  • In Cabbage and Brussels seen as  Internal browning.
  • In Carrot – develop Cavity spots – oval spots develop into craters which may be invaded by other diseases.

Cause : Very high acidic conditions (low pH) results in Calcium being less available and plants are unable to take it up.  Excessive application of Ammonium and Potassium fertilisers can also results in deficiencies of Calcium.


  • Firstly check the pH and make sure soil or potting mix is not highly acidic, maintain neutral pH condition (6-7)
  • Application of Calcium rich products such as Calcium Sulphate (Gypsum), Calcium Nitrate  or soluble fertilisers enriched with Calcium such as MANUTEC TOMATO MAGIC.
  • Water plants in a regular pattern or schedule
  • Balance use of Calcium, Magnesium and Potassium is also important as they complement and absorbed in preference to other when available in excessive.

Magnesium Deficiency

Symptoms : Patchy yellowing between the leaf veins of older leaves, sometimes with reddish brown tints and early leaf fall. Magnesium deficiency is common in tomatoes, apples, grape vines, raspberries, roses and rhododendrons. Very common in fruits, vegetables and acid loving plants such as azalea, camellias and rhododendrons.

Cause: Deficiencies of Magnesium are more common on light, sandy soils. Over-use of high-Potassium fertilisers or Potash can cause Magnesium deficiency, as plants take up Potassium in preference to Magnesium. Deficiencies are also common in acidic soils with low pH and in soils that are too wet or too dry restricting root growth

Remedy : For immediate and short term remedy, apply Manutec Epsom salts by dissolving in water either as foliar spray or applying solution to plants surrounding roots. In the long term regular application of Manutec Epsom Salt or Manutec Trace element mixes containing Magnesium will maintain adequate levels of Magnesium in soils. In acid soils where Lime has to be used to raise the pH, use Manutec Dolomite lime (instead of Garden Lime) which also supplies adequate Magnesium to soils. However care should be taken to not use Dolomite or Lime around acid Loving plants such as azalea and camellia.

Sulphur Deficiency:

Symptoms : General yellowing of new leaves including veins, in some plants leaves will be small with rolled down edges.

Cause : Sulphur is important for formation of proteins. Cabbages, onions and Brussels sprouts are crops that really do requireSulphur (the characteristic smell in these plants is from Sulphur). Alkaline soils, sandy soils, high rain fall areas, and potting mixes are commonly deficient in Sulphur.

Remedy : Application of Manutec Sulphur containing fertilisers such as Super Phosphate or Elemental Sulphur (partially in alkaline soils) helps to maintain adequate levels of Sulphur. Use of some Sulphate based fertilisers also adds Sulphur content to soils.