Yellow/Brown on Dieffenbachia Leaves

Hello Judy! It’s Stephanie from Northwest Territories Canada again! I hope all is well with you. I am worried about this beauty. I am not sure if the yellow leaves and the dying tips are from over watering or the pellet stove making it very dry. Right now the first inch of soil is dry but the rest is lightly moist. Any thoughts?

 

Hi Stephanie,

Here are some reasons what might cause yellow/brown on dieffenbachia leaves: 
Excessive fertilizerPlants need fertilizer only when they are actively growing. Slow growing plants in low light require very little plant food. Too much fertilizer is worse than not enough. Most plants prefer a water soluble plant food at 1/2 the recommended strength. Plants that are in bloom or dormant should not be fertilized. Houseplant food contains nitrogen (N), phosphorus (P), and potassium (K). A fertilizer containing these elements in equal proportion is considered a balanced plant food. Nitrogen helps in photosynthesis and encourages the growth of leaves and stems. Potassium and phosphorus also help in photosynthesis and aid in root and flower development. Most fertilizers have trace elements of other minerals that are lacking in the soil but are necessary for good plant growth. Fertilizers have a high salt content. If a plant is not producing new leaves and doesn’t absorb the fertilizer, salts build up in the soil. These salts can burn the roots, discolor the leaves, and cause new growth to be small. or too many chemicals in the water you are using. To get rid of accumulated salts, chemicals, and fertilizerPlants need fertilizer only when they are actively growing. Slow growing plants in low light require very little plant food. Too much fertilizer is worse than not enough. Most plants prefer a water soluble plant food at 1/2 the recommended strength. Plants that are in bloom or dormant should not be fertilized. Houseplant food contains nitrogen (N), phosphorus (P), and potassium (K). A fertilizer containing these elements in equal proportion is considered a balanced plant food. Nitrogen helps in photosynthesis and encourages the growth of leaves and stems. Potassium and phosphorus also help in photosynthesis and aid in root and flower development. Most fertilizers have trace elements of other minerals that are lacking in the soil but are necessary for good plant growth. Fertilizers have a high salt content. If a plant is not producing new leaves and doesn’t absorb the fertilizer, salts build up in the soil. These salts can burn the roots, discolor the leaves, and cause new growth to be small., flush the plant with distilled water several times. Never use water that has passed through a softener (too salty). Allow your household water to sit out over night before using it. Fertilize only when the plant is actively producing new leaves. Most dieffenbachias need to be fed every two weeks in the summer and once a month in the spring and fall. Never fertilize in the winter. Excess plant food causes browning around the edges of the leaves. 
 
Brown tips on your dieffenbachia’s leaves could also be caused by uneven watering. Keep your watering practices a little more regular and never let your plant sit in water.  
 
 It also looks like the plant could use a good pruning to help it become a full bushy plant. I would cut the top 1/3 off the tallest stem. This plant is very poisonousAlways wear long sleeve shirts and gloves when pruning to prevent the toxic sap from getting on you. You can read more about poisonous houseplants in my book Don’t Feed me to Your Cat: A Guide to Poisonous Houseplants