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Why Is My Dieffenbachia Dying? (8 Common Causes)

Why Is My Dieffenbachia Dying? (8 Common Causes)

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A few months ago, a family friend gave me a dieffenbachia plant. I loved the beautiful color of the leaves. Everything was going fine; then, after a few weeks, I saw my dieffenbachia was dying.

I started getting concerned when the leaves turned yellow and the plant was withering away. I wondered why is my dieffenbachia dying?

Dieffenbachia, or dumb cane, is not difficult to grow, so what can cause this plant to die? Some of the main reasons your dieffenbachia is dying are: overwatering or underwatering, not enough nutrients in the fertilizer, keeping the plant at the wrong temperature, too much sunlight, etc.

I had no idea why my dieffenbachia was dying, so I thought I would call a friend that owns a nursery to help me. She gave me a lot of interesting information that helped me identify why it was dying and how to revive my dumb cane.

I wanted to share the information in this post to help someone else who might have the same problem.

Why Is My Dieffenbachia Dying?

The dieffenbachia plant, also called the dumb cane, is relatively easy to grow and keep healthy, but certain external factors can cause the plant to wither and die. Some of the reasons we will look at in more detail include:

  • The pot your dieffenbachia is in
  • If you keep the dieffenbachia at the wrong temperature
  • If the dieffenbachia is exposed to too much direct sunlight
  • When you overwater the plant
  • When you underwater, the plant
  • When the fertilizer doesn’t have enough nutrients
  • Pest infestation
  • Plant diseases

1 – The Pot, Your Dieffenbachia Is Kept In

Choosing a pot for your plant might not seem like a big deal to you, but you need to choose the appropriate pot. Dieffenbachia plants have extensive root systems and need enough room to grow. Thus if you buy a pot that is too small or a pot that is not strong enough to hold a growing plant, a few things will happen;

  • The ground will get compacted as the root system expands
  • If the roots get big enough, the pot might break
  • The plant will suffocate without enough space

2 – Keeping the Dieffenbachia at the Wrong Temperature

Because the dieffenbachia is a tropical plant, it needs a hot and humid environment to grow adequately. Therefore, you need to keep your plant in a warm room, or the leaves will start to droop, and the plant will die. The ideal temperature for your dieffenbachia is between 65-75 degrees Fahrenheit.

If the room you put the plant in only has the right temperature but not a lot of humidity, you can try to use a humidifier to create the optimal temperature and humidity to ensure your dieffenbachia has the best chance to stay healthy.

3 – When the Dieffenbachia Gets Too Much Sunlight

Dieffenbachia plants need sunlight to thrive but not too much sunlight. If you place your plant in direct sunlight, it might burn the delicate leaves. It also can’t grow in the shade, so you need to find the correct balance between sunlight and shade.

The best place to put your dieffenbachia is in spotted sunlight or shaded sunlight. It should be fine if you don’t expose it to direct sunlight. However, you might have to move the plant in the wintertime as the sunlight might not be enough, and the room might become too cold. So you might need to change where you put your plant depending on the season.

4 – If You Overwater Your Dieffenbachia

Plants need water to survive, but if you give your dieffenbachia too much water, the leaves will turn brown, and the plant might start to get a moldy, rotten smell. That means the roots might begin to rot. Overwatering your plant can lead to several different diseases, so you must give the right amount of water.

When you suspect you are overwatering your dieffenbachia, you need to ensure it actually needs water. Before you water your dieffenbachia, you must feel the first two inches of soil. If the potting soil feels dry, then it’s time to water your plant, but if it feels moist, you should leave it until those top two inches are dry.

5 – If You Underwater Your Dieffenbachia

If you underwater your dieffenbachia, the leaves will droop, and the plant will slowly dry out and die. The optimal soil will be damp but not very moist. You test the soil in the same way as the previous heading by feeling the first two inches of topsoil. If you feel more than the top two inches of soil are dry, you need to water your dieffenbachia more often.

6 – When the Fertilizer Has a Lack Of Nutrients

Like all other plants, dieffenbachia sometimes needs help to grow, and fertilizer is the answer. However, if you are giving the wrong dose of fertilizer or the wrong kind of fertilizer, it can negatively affect your plant.

When you give too much fertilizer, the roots will burn, and the plant might not get the right amount of nutrients. On the other hand, if you don’t give enough fertilizer, it might stunt your plant’s growth. You can give liquid fertilizer once every four weeks. Follow the instructions on the label, and your dieffenbachia will thrive.

Drooping Yellow Leaves

If you see your dieffenbachia has drooping yellow leaves means your plant is wilting. This is due to inconsistent watering. You need to set up a watering schedule to ensure that you water the plant regularly and in the right amounts.

Browning Margins

When your dieffenbachia has browning margins, it means that the plant wasn’t watered before you added liquid fertilizer. It might also be because you use too much of it. You must leach the soil if it doesn’t have fertilizer pellets to combat this. You should use less fertilizer or no fertilizer for a while until your plant is healthier.

7 – Pests Can Kill Your Dieffenbachia

Like most other plants, dieffenbachia can get pest infestation. These tiny bugs can destroy your plant if you don’t take care of the problem as soon as you find it. Like most plants, your dieffenbachia is susceptible to mealybugs, spider mites, and lice/aphids. You can identify these bugs by looking at the underside of the leaves.

If your dieffenbachia has spider mites, you will see small white dots on your plant and its leaves. If you see bugs clumped together and look like clouds, it’s likely mealybugs. Lice are tricky as they can adapt their color to blend in with their environment.

They are tiny bugs that might look red, white, brown, grey, green, or yellow. To prevent these aphids and other bugs from infesting your dieffenbachia, you can use an eco-friendly insecticide or make your own organic pesticide at home.

How to Make Your Own Organic Insecticide

If you find that your dieffenbachia has a bug infestation, you can buy or make organic pesticides to get rid of the bugs without harming your plant or the environment. Here is how to make an organic insecticide at home:

You will need the following supplies to make your organic insecticide:

  • A spray bottle
  • Two bulbs of garlic
  • Some dish soap
  • Vegetable Oil
  • Water
  1. The Method You Use

Here is how you make your own insecticide:

  1. First, you need to purree both garlic bulbs, adding a little water to make it easier. You’re looking for a watery baby food consistency.
  2. Let the mixture sit overnight, then the next day, you strain the garlic from the water into a quart jar.
  3. Then you must add half a cup of oil (the oil will help the mixture stick to the leaves longer, thus working faster).
  4. Next, add a teaspoon of liquid dish soap (use mild dish soap).
  5. Now that you concentrate, you need to add one cup to a quart of water in your spray bottle.

Spray this mixture liberally over the infected plant and soil. Do this every day until the bugs are gone; then, you can spray it once a week to ensure you keep the bugs away.

8 – Plant Diseases That Can Kill Your Dieffenbachia

If you don’t find any bugs and there is nothing else wrong, your dieffenbachia might have a plant disease. Some of the diseases that your plant can get include:


It’s a fungal disease that presents in small brown oval or round spots that are surrounded by a yellow halo. They spread when you overwater your plant, so it’s essential to water the roots of your dieffenbachia and not the foliage. Water that leaks from an infected plant to other plants are particularly damaging.

Bacterial Leaf Spot

Bacterial leaf spot is green, black, or brown when the spots begin to form. As the infection progresses, the appearance of the spots will become irregular and turn brown or black. In these cases, you need to water only the roots and only when needed.

You must keep the leaves dry and remove all the dead and damaged foliage. Remember to wipe your shearing scissors with rubbing alcohol before beginning, and after each cut so you don’t spread the disease from the infected parts to the healthy parts of the plant.

Myrothecium Leaf Spot

This disease presents with big grey spots. Then in the center of these spots, concentric fungal fruiting circles form on the underside of the leaf. You usually find them on the margins or the tips of the plant. If you find this issue on your plant, you treat the plant with a fungicide, remove the dead leaves and debris, and limit fertilizer with nitrogen.

Tips to Keep Your Dieffenbachia from Dying

If you need more help in keeping your dieffenbachia from dying, here are some tips that might help you:

  • You can prune your dieffenbachia now and then to keep it healthy. However, some of the lower branches might be “suckers” that don’t help your plant grow but leech all the nutrients from the soil.
  • People keep dieffenbachias because of their longevity, but like all living things, these plants age. So when you see the leaves fall off on their own, you need to cut back foliage and trim the stems to encourage new growth.
  • Try not to put your dieffenbachia in rooms with air conditioning, the leaves will droop, and the plant will die.
  • You can add Epsom salts to your dieffenbachia. Once a month, you can add 30ml Epsom salt to a gallon of water. Only water the plant like you usually would. It acts as plant food and stimulates growth.
  • Be careful where you put your dieffenbachia; the leaves are toxic to dogs, cats, and other pets.
  • You can take your dieffenbachia outside in the summer as it loves to be outdoors. However, you must take it inside to a warm room with ample shade and sunlight in the wintertime.
  • If you don’t have a room with enough light or warmth, you can add a grow light in the winter months to keep your plant healthy, and it encourages your plant to bloom.
  • If you are concerned about the moisture in the soil, you can buy a moisture gauge. It will allow you to see how much water is in the soil, when you need to add water and how much you need to add.
  • You can use a slow-releasing fertilizer if you don’t want to use too much or you want to keep your plant fed for longer.
  • To prevent your plant from leaning to one side as it grows, you need to rotate the plant every time you water it. If it grows too tall when leaning, the stems might break. In addition, it will encourage the dieffenbachia to grow upright.

Final Thoughts

Suppose you see your dieffenbachia or dumb cane plant is dying. If this is the case, you should think about the conditions of the room you have it in as things like too much sunlight, too much water, not enough nutrients in the fertilizer, and over and underwatering can all cause this plant to die.

Plant diseases, fungus, and infections may also be to blame for the demise of your plant. Pests can also cause your plant to die, so you need to protect your plant with an organic insecticide to keep it healthy. If you keep an eye on these things, your dieffenbachia will be happy and healthy.

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