Dennis Wong
Active Member
Planted aquarium meme of the day:
Why? Because pinholes and yellowing edges on leaves of plants can happen due to many other causes and may not be related to potassium deficiency at all.
For example, transferring plants into a new environment triggers adaptation stress - the plant will produce new leaves adapted to the new environment, and old leaves are often abandoned, as the old leaves deteriorate, you will see yellowing or pinholes forming. This adaptation change happens regardless of potassium availability.
Any number of environmental stress factors, from inadequate CO2, to overly alkaline water (for soft water plants) can cause leaf yellowing and holes in older growth. More on the leaf renewal cycle here: Why do leaves deteriorate? Understanding the leaf renewal cycle in aquatic plants
How do you actually know if an issue is potassium related?
By inductive reasoning and testing - If you are regularly dosing fertilizer that contains potassium, and we know that potassium is readily taken up aquatic plants through their leaves, the chance of having true potassium deficiency is greatly reduced. Potassium test kits exist - and can show if it is present in the water or not. By the time you add enough potassium to hit XX+ppm range and nothing changes - its time to rule it out and move on.
There are a ton of other factors to consider in an aquarium - carbon sufficiency, stability of nutrient levels, root zone compaction, plant competition and over crowding etc:
A longer list can be found here:
Nutrient Tunnel Vision
Is my aquatic plant suffering from a nutrient deficiency? How do I diagnose nutrient deficiency issues? Are there other factors that affect plant growth besides nutrients? This page aims to explain how many factors besides nutrients can affect aquatic plant health.
www.2hraquarist.com
