Potassium

Deficiency Symptoms:

Leaf tip yellow or brown.  Yellowing spreads from the tip onward along he leaf margin and may coalesce with similar areas at extremities of the lateral veins.  Leaf tip becomes scorched as symptoms become more severe.  The scorching may spread around the leaf margin but typically there is a yellow band between the scorched area and the healthy green tissue in the early stages.  The affected leaves not showing symptoms are generally dark green.  Plants stunted.

Foliar spray of KCl 1% at weekly intervals.