What is a nutrient deficiency?
A true deficiency occurs when the plant does not receive or acquire enough of an essential nutrient to maintain normal growth and development.
Avoiding meaningful deficiency is important, but identifying the cause correctly matters just as much as recognizing the symptom.
Visual symptoms are useful, but not perfect
Leaf appearance can provide clues involving older or younger leaves, chlorosis, necrosis, distorted growth or margin damage. Symptom charts should not be treated as laboratory tests.
Professional diagnosis uses multiple signals.
Deficiency vs availability problem
A nutrient can exist in the reservoir and still fail to reach the plant effectively. Root-zone pH, root health, moisture, oxygen, EC, irrigation and nutrient interactions can all influence uptake.
Adding more fertilizer to a system that already contains sufficient nutrients can make diagnosis harder.
Start with the basics
Before changing the nutrient program:
- Verify products and mixing
- Check source water
- Check input EC and pH
- Confirm irrigation delivery
- Review environmental or crop-stage changes
Check the root zone
Look beyond the leaf. Consider substrate moisture, root-zone EC, irrigation frequency, drainage, temperature and root condition.
Is the whole crop affected?
If an entire room changes at the same time, inspect variables shared across the room. If only isolated plants are affected, inspect local irrigation, root health or plant-specific factors.
Recent changes matter
Ask what changed before the symptom appeared: nutrient program, transplant, water source, irrigation, environment or crop stage.
Do not correct everything at once
Changing several variables simultaneously makes diagnosis difficult. Correct the most likely cause, observe the response and keep the information for future cycles.
Calcium and magnesium
Calcium and magnesium issues are often discussed in soilless cultivation, especially Coco and low-mineral source water. Do not automatically add CalMag.
Consider source water, substrate preparation, base nutrient composition, EC, pH and root conditions first.
More fertilizer can create a new problem
Overcorrection can increase EC while failing to resolve the original limitation. Correct the cause, not the anxiety.
Technical support
When contacting CANNA Thailand, useful context includes the CANNA system, substrate, crop stage, source-water EC, current EC/pH, irrigation setup, symptom distribution and recent changes.