Fertilizer damage on poinsettia
Updated: March 16, 2021

High soluble salt levels are caused by the excessive use of fertilizers, frequent applications of fertilizer, and the incorrect use of fertilizer concentrates.

Symptoms of fertilizer toxicity

  • The typical symptoms are browning or dieback of the leaf tips and margins. But can include reduced growth, lower leaf drop, dead root tips, and wilting. 

  • Sometimes yellowing or stunting may occur. The root systems will also show dieback and decay.

  • Fertilizer salts may also accumulate on the surface of the potting media as a white crust, especially if bottom watered, and cause stem collapse at the soil line.

  • Salt deposits may be visible on the outsides of pots.

Management

  • Use the proper fertilizer analysis at the correct rate and frequency.

  • Large pots with growing media that have excessive salts can be flushed or leached by irrigating with clear water.

  • Allow the water to run out the bottom of the pot and repeat the several irrigations with a volume at least that of the pot size.

  • Smaller pots with media high in salts should have the growing media replaced.