Monitor plants closely for symptoms of nutrient deficiency. These symptoms
can provide a valuable forewarning of serious problems within the growing
system. Be aware that there are many factors that cause nutrient deficiency
symptoms in a plant. The nutrient itself is usually not the cause.
Deficiency symptoms (see Chart 15.20) are grouped into several
1. Stunting of growth: As all “essential” nutrients are
simultaneously required for healthy growth, this symptom can be attributed
to a deficiency in any one or more of them.
2. Chlorosis & interveinal chlorosis: Chlorosis can result in
the whole plant or leaf turning light green or yellow.
can also be more localized. For example, yellowing of the veins themselves
or between the veins (“interveinal chlorosis”). Chlorosis occurs due to
plants being deficient in elements required for photosynthesis or
3. Purple / red discoloration: This often occurs on stems or along
leaf petioles, veins or margins. It occurs due to abnormal levels of
anthocyanin that accumulates when plants are stressed. These symptoms can
also be caused by physical stresses such as cold, drought and disease.
Generally happens in the later stages of deficiency where the affected plant
part becomes stressed to the point that it becomes brown and dies.
5. Other: Further symptoms include:
- Poor quality (or few) buds, flowers or fruit.
- Poor root development.
- Distorted leaves i.e. cupped or twisted.
For information on nutrient toxicity (excessive
Old or young growth
A key indicator for identifying nutrient deficiency is whether the symptoms
are occurring in older growth, younger growth, or both.
Mobile elements are able to move out of older leaves and into younger plant
parts when a deficiency is present. Hence the symptoms usually occur first
in the older (usually lower) leaves. Mobile elements include N, P, K and Mg
In contrast, immobile nutrients are not able to move quickly from one plant
part to another. Therefore, deficiency symptoms are initially most obvious
in younger growth (usually higher up the plant). Immobile nutrients include
Ca, S, Fe, Cu, Mn, Zn and B (Chart 15.20).
What causes deficiency symptoms
The appearance of foliar deficiency symptoms often causes inexperienced
growers to conclude that the nutrient solution is deficient in a particular
element. However, if a ‘complete’ (see
Table 7.20) nutrient formulation is being used, check the following
before settling on this conclusion:
- Insufficient EC or
- In recirculating hydroponic systems, the nutrient is
discarded too infrequently.
- Inappropriate nutrient pH: Causes certain
nutrient elements to become unavailable for uptake.
- Excessive humidity: Hinders the
distribution of nutrient throughout the plant.
- Signs of pests or
diseases: Their presence can
produce symptoms that are similar in appearance to nutrient deficiency