Essential Mineral

• Potassium is one of 16 essential minerals that ornamental plants need to thrive in any environment. Without potassium, plants, especially the more delicate ornamental varieties, cannot synthesize protein, which basically means they can't build up or repair their cells.
  
  

Symptoms

• A potassium-deficient ornamental plant has brown, burnt-looking leaves, curled up leaf tips and yellowing leaf veins. The undersides of the leaves may have purplish or blackish spots. These symptoms may be confused with drought or wind scorching; if proper watering and care do not solve the problems, though, they may be symptoms of potassium deficiency.
  
  

More Effects

• Ornamental plants exposed to a long period of potassium deficiency lose basically all of the qualities that make them beautiful and ornamental. Potassium-deficient plants are easy to recognize because they have stunted growth, weak stems and off-colored leaves. Generally, they also are more prone to damage from frost and diseases.
  
  

Treatment

• Ornamental plants with potassium deficiency are treated with potassium (also called potash) fertilizer to improve the soil and to help restore the potassium balance in the plants. Greensand, available at most nurseries, is also high in potassium and helps to restore an ornamental plant to full health. Compost made from food byproducts high in potassium, including banana peels and potato skins, is another treatment.
  
  

Prevention

• Testing the pH and nutrient content of soil and making necessary adjustments before planting ornamentals can prevent potassium deficiency. Fertilizers, potting soil and minerals can be used to improve soil before planting.
  
  

Warning

• Sometimes potassium deficiency in ornamental plants happens in combination with a phosphorus deficiency, which may cause ornamental plants to turn a sickly orange-red color along with all of the disturbing signs of potassium deficiency.