Extract from the BNCS year Book 1963
To find the cause of any problem, relating to nutrient deficiency, all the possible combinations of causes, both physical as well as chemical, must be examined thoroughly before a diagnosis can be ascertained.
Here is a list of combinations of causes.
Soft growth
Excess nitrogen
High temperatures
Excess moisture
Low prevailing light intensity
Hard growth
Excess potash
Lack of moisture
Lack of plant food (starvation)
High salt concentration
Stunted growth
Low nitrogen
Phosphate deficiency
Low temperatures
Lack of moisture
Browning leaf tips
Excess boron
Sunscorch
Calcium deficiency
Spray damage
Poor root system
Phosphate deficiency
Over watering
Dry conditions
Low pH.
Lack of calcium
High salt concentration
Disease
Blooms small
High temperature
Low nitrogen level
Phosphate deficiency
Cold, dull weather
Boron deficiency
Excess potash
From the above list you will see that one symptom may be caused by any number of circumstances, relative to nutrients or physical conditions, or both.
You might also consider your growing method, outside in the open ground, or pots, inside in pots, or beds, or hydroponics. Do you use the best planting and feeding material available and provide the optimum growing conditions?