Dieffenbachia Common Problems Indoors and Treatment (Dumb Cane Issues Indoors)

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Dieffenbachia indoor growing problems include yellow leaves, soft mushy stems, brown leaf tips, brown leaves, leaf spots, leggy growth, pests and diseases among others. Keep reading for more on these problems, their remedies and solutions.

Dieffenbachias commonly called Dumb Canes are popular tropical foliage plants grown for their large, highly decorative leaves and their air cleaning properties.

Dieffenbachias grow best in bright indirect light, average warmth of 18-26, humidity of 50-55% and moderately moist, fertile, well-drained, all purpose potting soils coupled with fortnightly feeding during the growing season. Read more on how to grow and care for Dieffenbachias.

If the correct growing conditions are not provided, Dieffenbachias may develop some problems. We have herebelow outlined for you these problems and how to fix them.

Dieffenbachia Common Issues Indoors & How to Fix Them

1. Yellow leaves

Yellowing leaves in Dieffenbachia is very common but is easy to resolve. Here are 8 common reasons for Dieffenbachia yellow leaves.

(a) Aging

This is a natural phenomenon where the older lower Dieffenbachia leaves will turn yellow and die to allow the plant to grow new leaves. Remove the yellow leaves to maintain the plant neat and tidy.

(b) Too low temperature

At temperatures below 15⁰C due to exposure to cold drafts, the Dieffenbachia leaves will begin to yellow and die. Maintain an average warmth of 18-28⁰C and keep the plant away from cold drafts like windy doors and windows, air conditioning units among others. Check out this guide on understanding temperature for houseplants.

(c) Overwatering

Overwatering Dieffenbachia results in excess water in the soil which causes the soil to be soggy. Too much water in the soil reduces the oxygen concentration in the rootzone which causes the roots to die.

When roots die, they cannot take up water and nutrients to the upper parts of the plant including the leaves and this implies that they cannot make enough food needed for growth and energy.

Therefore, the plant begins to die and death begins from the leaves which turn yellow and die. To avoid getting soggy soil, ensure that the pot has a drainage hole and that the soil is well-drained.

(d) Underwatering

Underwatering Dieffenbachia implies that there is too little moisture in the soil. As such, there is no water in the soil for the plant to take up to the leaves and other parts.

Therefore, the plant cannot make enough food for growth and energy. As such, the plant begins to die from the leaves which turn yellow, then brown and die.

Water the plant liberally during the growing season and allow the top 1-2 inches of soil to dry out between waterings to keep the soil consistently moist. Reduce watering during the cold season but do not allow the soil to dry out completely. Learn more on how to water houseplants the right way.

(e) Too Little Light

If the light is insufficient the plant cannot make enough food for energy and growth. In an attempt to save energy, the Dieffenbachia begins to die. The death of the plant begins from the leaves which slowly turn yellow and eventually die.

Move the plant to a brighter spot where it will receive bright indirect light or instal a grow light if you do not have adequate natural lighting in your home. Check out these full spectrum grow lights on Amazon.

(f) Underfeeding

Underfeeding means that the Dieffenbachia is not getting enough nutrients that are needed for growth and energy. Lack of adequate nutrients in the actively growing tips causes nutrients to be withdrawn from the older lower leaves which begin to yellow and drop.

Feed your Dieffenbachia every 2-3 weeks during the growing period with a balanced, water-soluble fertilizer to encourage foliage development. Make sure to follow the instructions on the label of the plant food.

(g) Overfeeding

Overfeeding your Dieffenbachia will cause the roots to die due to fertilizer burn. When the roots die, they cannot take up water and nutrients to the leaves.

The lack of nutrients and water needed for making food for growth and energy signals death for the plant which begins from the leaves. The leaves turn, yellow, brown and eventually die.

Take care not to overfeed your plant. Ensure to follow the instructions on the label of the plant food to avoid overfeeding.

Regularly flush out the salts from the soil by running a stream of water through the soil until it comes out through the drainage holes and repeat the process several times.

(h) Pot-bound plant

If the Dieffenbachia is pot-bound, the roots have filled the pot and there is very little soil to hold water when you water the plant.

This implies that the plant cannot take up water and nutrients to the leaves for making food needed for energy and growth. Lack of adequate food causes the plant to begin dying which starts from the leaves turning yellow.

Check the bottom of the pot for roots growing through the drainage hole. Repot the plant into a pot one size larger than the current one to provide adequate room for growth. Check out these pots drainage holes on Amazon.

2. Brown leaf tips

Dieffenbachia brown leaf tips are caused by 3 possible reasons. Trim off the brown tips with sterilized scissors and ensure to maintain the normal leaf shape.

(a) Low humidity

If the temperatures are very high, they cause the air to become too dry (low humidity) and this results in the Dieffenbachia developing brown leaf tips. To increase humidity, set the pot on a wet pebble tray or use a cool mist humidifier. Check out these techniques on how to raise humidity for houseplants.

(b) Low soil moisture

Keep the soil consistently moist at all times during the growing season. Cut down on watering in the cold season but do not allow the soil to dry out completely.

(c) Cold drafts

Protect the Dieffenbachia from cold drafts or keep it away from cold air to maintain an average warmth of 18-28⁰C with a minimum of 15⁰C.

3. Soft, mushy stem

Soft mushy stem in Dieffenbachia is an indication of stem-rot disease which is promoted by soggy soil and low temperatures. Cut out diseased parts and treat the plant with a fungicide. If badly damaged, discard it as it is too far gone.

Avoid soggy soil in the future by ensuring that the pot has a drainage hole and the soil is free-draining. Maintain the room temperature at 18-28⁰C and keep the plant away from cold drafts.

4. Brown leaf spots

Dieffenbachia brown leaf spots may be due to 4 possible reasons. Cut away the affected parts and discard.

(a) Soggy soil

Ensure that the soil for Dieffenbachia is free-draining and that the pot has a drainage hole to prevent the soil from getting soggy. Reduce watering in the cold season to keep the soil slightly moist.

(b) Sudden temperature drop

Protect the Dieffenbachia from cold drafts or keep it away from drafts to prevent sudden drops in temperature and to maintain an average warmth of 18-28⁰C with a minimum of 15⁰C.

(c) Hot direct sunlight

Exposing the Dieffenbachia to hot direct sunlight will cause brown sunscorch marks. Provide the plant with bright, filtered light and protect it or keep it away from direct sunlight.

(d) Leaf spot

Dieffenbachia is susceptible to leaf spot disease which is common in warm, damp, stuffy conditions. Look out for brown, moist spots on the foliage which may enlarge, merge and kill the whole leaf.

5. Brown leaves

The lower leaves in Dieffenbachia may turn brown and droop due to age. Remove the brown leaves by cutting with a sharp knife and not pulling to avoid excessive injury as it can lead to fungal diseases infestation.

If browning of leaves in the Dieffenbachia is general and accompanied by rotting, the reason is root-rot disease which is prevalent in soggy soil.

6. Leggy growth and small leaves

Leggy growth and small leaves in Dieffenbachia is caused by too little light. Position the plant in a brighter spot and ensure it is receiving bright, indirect light away from direct sunlight.

7. Loss of leaf color or variegation

Exposing Dieffenbachia to direct sunlight or excessive brightness will lead to loss of leaf color. Move the plant to a more shaded spot or shield it from direct sunlight by installing a light curtain.

8. Diseases

Dieffenbachia is prone to 3 common plant diseases which if not attended to properly may lead to the death and loss of the plant.

(a) Root-rot disease

Root-rot disease is a fungal disease prevelant in soggy soil. It is characterized by yellowing and wilting of the leaves which is rapidly followed by browning and plant collapse.

Take the Dieffenbachia out of its pot and inspect the roots. Brown mushy roots indicate root-rot. Cut the brown-black roots and treat the healthy roots with a copper-based fungicidal solution.

Repot the Dieffenbachia in fresh soil and keep it dry for some time before resuming watering. Always ensure that the pot has a drainage hole and that the soil is free-draining to prevent it from getting soggy.

In addition, reduce watering in the cold season as growth is minimal at this time therefore, the plant does not need much water.

(b) Stem rot disease

Stem rot disease is characterized by part of the stem turning soft and rotten. It is is a fungal disease prevelant in wet, cool and poorly ventilated growing conditions which spreads rapidly and kills the plant.

If caught early, the disease can be treated but if it has spread, the plant cannot be saved and it should be discarded. To save a plant that is in the early stages of infestation, cut away and discard or burn the diseased tissue.

Keep the soil on the drier side; avoid soggy soil by ensuring that the soil is free-draining and the pot has a drainage hole. Ensure that there is free air circulation and avoid keeping the plant in very cold conditions.

If the plant is too far gone, discard or burn it. Discard its pot and the soil as the treatment is not effective and may spread to the rest of the plants.

(c) Leaf spot disease

Leaf spot disease is characterized by brown, moist spots on the Dieffenbachia foliage. In a serious attack the spots can enlarge and merge, killing the whole leaf.

Remove and burn the affected parts of the plant to reduce the risk of spread to the rest of the plants. Keep the plant on the dry side and do not mist it.

Spray the affected plant with a systemic fungicide and ensure that all the parts are completely covered with the fungicidal solution.

9. Pests

The common pests in Dieffenbachia are scale insects and spidermites. Isolate the affected plant to prevent spread to other plants and treat it with insecticidal soap or neem oil as per the manufacturer's recommendations.

10. Toxicity

Dieffenbachia are toxic to both humans and pets as indicated by the ASPCA. If ingested, they may cause temporary swelling of the tongue and the throat which may lead to a temporary loss of speech and hence the common name dumb cane. In severe cases suffocation may occur.