⚠ ModeratePotassium deficiency scorches the margins and tips of older leaves while the centre stays green — a mobile-nutrient pattern distinct from uniform nitrogen yellowing.
Potassium Deficiency — Marginal Scorch
Commonly affects: Monstera deliciosa, Philodendron spp., Alocasia spp., Anthurium andraeanum
Older leaves develop yellowing and browning along their margins and tips while the centre stays green, the scorched edges progressing inward and often curling. Because potassium is mobile, symptoms appear on the oldest leaves first. The pattern — a scorched margin around a green interior — distinguishes it from the uniform yellowing of nitrogen deficiency.
Potential Causes
- 1Depleted potassium in exhausted or unfertilised substrate
- 2Heavy leaching from frequent watering removing mobile potassium
- 3Imbalanced fertiliser low in potassium relative to nitrogen
- 4Excess calcium or magnesium competing with potassium uptake
Solution Steps
- 1Apply a balanced fertiliser with adequate potassium (the 'K' in NPK) at the correct dilution.
- 2Correct any fertiliser imbalance that is overloading nitrogen at potassium's expense.
- 3Repot into fresh substrate if the mix is old and nutrient-depleted.
- 4Flush the substrate first if salt build-up may be hindering uptake, then resume balanced feeding.
- 5Maintain consistent feeding through the growing season to prevent recurrence.
- 6Trim badly scorched leaf margins for appearance; new growth should emerge normal.
Prevention Tip
A balanced complete fertiliser supplies potassium alongside nitrogen and phosphorus — deficiency usually reflects an exhausted mix or a lopsided feed. Refresh substrate periodically and avoid heavy nitrogen-only feeding that drives potassium out of balance.
Related Issues to Explore
Nitrogen Deficiency — Uniform Pale Older Leaves
Both affect older leaves first as mobile nutrients — nitrogen yellows uniformly, while potassium scorches the margins.
Read guide
Brown, Crispy Leaf Tips — Low Humidity & Salt Stress
Marginal scorch from potassium deficiency resembles humidity- and salt-related tip burn — the deficiency starts on the oldest leaves specifically.
Read guide
Salt Crust & EC Build-Up in Substrate
Salt build-up can both mimic and cause potassium problems by impairing uptake — flushing the substrate is a shared first step.
Read guide
