Fulvic acid is the fraction of humic substances that remains soluble at all pH values. Its molecules are smaller and richer in oxygen-containing acid groups than humic acid, so it binds metal ions and moves more freely in water. It is usually yellow to golden brown.
In practice
It is sold as a nutrient carrier, foliar additive and "uptake enhancer". It does complex micronutrients, which may help keep them soluble. Claims that it dramatically improves uptake, yield or quality in cannabis lack controlled trials (Evidence: Contested). Products vary widely in source and concentration, and the analytical methods for "fulvic content" are not standardised, so labels are hard to compare. Small doses are generally harmless; treat any large claims with suspicion.
Don't confuse with
- Humic acid: the larger fraction that precipitates at low pH.
- Synthetic chelates: defined chemicals with known stability.
- Shilajit or similar supplements: human products marketed with fulvic claims, unrelated to plant feeding.
Myth check
Label claims for fulvic products often outrun the evidence. See buyer beware: label claims.
