I'm leaning toward Magnesium deficiency HB.....
Quote:
Magnesium deficiencies show first in older, lower leaves. The symptoms start from the margin inwards. The leaf mid-rib and veins remain green while leaf margins are yellow or whitish....
Excess magnesium interferes with calcium and potassium uptake.
Plants use magnesium to: produce chlorophyll; regulate enzymes for transport of nutrients and carbohydrates in the plant; cell replication; seed production.
Magnesium is an important co-factor in production of ATP, the compound that helps plants transfer energy. It is also a bridge between ATP and enzyme activity.
Flowering and fruiting plants use more and more magnesium as they progress towards maturation and harvest.
Magnesium helps plants generate energy through photosynthesis and is also crucial to protein synthesis.
Are you "fertlising" your system with any additives....
An over fertilisation of magnesium can become toxic, preventing calcium and [s]phosphorus [/s] potassium from being absorbed....
Calcium is essential for cell wall strength and potassium generally results in lusher leaf growth and is critical for flower set and fruit development....
So all in all.... I'd say a deficiency.....
Some of the permaculture people might be able to confirm?
Backyard Aquaponics
