Ten Common Houseplant Problems

David Deardorff

David Deardorff

We’ve prepared a list of the ten most common problems of houseplants. If you’re having a problem with a houseplant, it’s most likely going to be due to one of the following.

1. Overwatering.

More houseplants die from overwatering than from any other cause. Never let the pot sit in water in a saucer. Put marbles or pebbles in the saucer and set your pot on top of them to raise the pot up and away from the water in the saucer. Make sure the pot has adequate drainage holes. Allow soil to dry out in between watering. When you water, water the root zone of the plant, not the foliage.

This crown-of-thorns houseplant struggles to survive in a pot without drainage holes.

This crown-of-thorns houseplant struggles to survive in a pot without drainage holes.

2. Air is too dry.

Keep all your houseplants away from heat sources like heat registers, electric heaters, or radiators. Hot air blowing on a plant will quickly desiccate it. Mist plants to increase humidity, especially if you live in a dry climate. It also helps to place pots on shallow gravel filled trays of water.

Dry, brown, dead tissue shaped like an upside down V at the tips of the leaves tells you conditions are too dry for your plant.

Dry, brown, dead tissue shaped like an upside down V at the tips of the leaves tells you conditions are too dry for your plant.

3. Not enough light.

Put the right plant in the right place. Consult plant labels and packaging, and reliable books, magazines, and internet sites to determine a plant’s light requirements. Plants that need full sun rarely make good houseplants. Plants adapted to the low light levels of tropical forests do quite well in our homes.

4. Ambient (room) temperature too hot (especially at night).

The best houseplants are all tropical species that are able to tolerate the warm nighttime temperatures we keep in our homes. Temperate zone plants are often killed by warm nights because they burn up more fuel than they are able to make. That’s why miniature roses do not survive indoors, they starve to death. Turn the thermostat down, especially at night, to 60 degrees.

5. Pot bound.

If your plant sucks up all the water you give it and then wilts a short time later it’s probably pot bound. Up-pot the plant to a larger pot and add fresh soil. This way you give the plant a larger volume of soil to plumb for moisture. Alternatively, take the plant out of its pot, shave off an inch of roots and soil around the sides and bottom of the root ball, then put the plant back in its pot with fresh soil.

5. Temperature, humidity and/or light regime changes, as when the plant is moved.

Some plants, like Bougainvillea and weeping figs, drop most of their leaves when you move them to a new location. Make the change gradually, if possible, and give the plant extra nutrients and water to cope with the shock.

6. Not enough water.

Determine the right amount of water for the particular plant (read the tag or look it up). Some plants, like cactus and succulents, require very little water. Other plants will tolerate being constantly waterlogged. Most plants, however, fall somewhere in the middle. In general, allow the soil to dry out in between watering and mist plants to increase humidity. Make sure the plant is not pot bound.

Mealybugs on the underside of this Hoya look like fluffy wads of cotton.

Mealybugs on the underside of this Hoya look like fluffy wads of cotton.

7. Insect pests, such as fungus gnats, whiteflies, mealybugs, and scale insects.

Plants under stress are more susceptible to pests. Make sure you put the right plant in the right place to reduce stress. Give it the proper amount of light and water, the best temperature regime, and soil conditions to allow it to thrive and you’ll have fewer problems. Wherever possible, choose resistant cultivars and always inspect and quarantine plants when you first bring them home.

Mulch or top dress containers. This helps to control fungus gnats.

Sanitize. Remove and destroy insect infested leaves or stems.

Remove any pests you can capture, either with your hands or use a vacuum cleaner.

Physical barriers like sticky cards work well for adult whiteflies and fungus gnats.

Provide air movement with a fan set on low.

Make sure your windows and doors have screens to reduce the number of insects in the house.

Insecticidal soap sprayed directly onto the pests will kill them and is safe to use in your home.

Use rubbing alcohol on Q-tips to grub out mealybugs.

Drench the pot with Bt-i (Bacillus thuringiensis israelensis) for fungus gnats

Spray Neem oil to control most houseplant insect pests.

Horticultural oil (look for ones made from vegetable oil).

Pyrethrins made from botanical sources also work well.

8. Spider Mites.

This is a common problem under dry, dusty conditions. Mites are not insects, they’re related to spiders. They are very tiny and hard to see. They come in to your house on infested plants.

Quarantine new plants until you’re sure they’re mite free.

Sanitize. Remove badly infested leaves and discard them.

Blast leaves with water to wash mites away. Keep the leaves free of dust.

Misting the foliage discourages mites (they don’t like water).

Insecticidal soap sprayed directly on the pests will kill them.

Neem oil controls mites.

Horticultural oil (vegetable oil base) smothers mites and their eggs.

Sulfur is a natural element that mites don’t like.

Pyrethrins made from botanical sources also work.

This philodendron shows the watersoaking typical of bacterial infections on the leaves.

This philodendron shows the watersoaking typical of bacterial infections on the leaves.

9. Diseases, such as fungus and bacteria.

Sanitize. Pluck off infected leaves and put them in the garbage. Do not compost.

Mulch. Top dress containers to reduce splash up from the soil to the leaves.

Provide air movement with a fan set on low. Don’t crowd plants. Put the right plant in the right place. Choose resistant cultivars and keep the foliage dry when watering.

A simple spray made from baking soda prevents fungal spores from germinating.

Sulfur sprayed onto the foliage also prevents fungal spores from germinating.

Copper sprayed on the leaves will kill bacterial pathogens.

Bacterial fungicide (Bacillus subtilis) is a living bacterial culture which kills fungi.

Neem (has a strong odor for some people) Keep it away from aquaria.

10. Nutrient deficiencies.

Start with a good quality potting soil, an artificial mix that contains perlite, vermiculite, and other materials that create space and air pockets, yet retain water. Some plants, such as orchids or cactus, need special mixes. Never use garden soil in a container because it will become very compacted over time. Use a good organic fertilizer whenever possible.

  1. I really needed these indoor plant tips. I see that I am drowning two of my plants. The more they drop yellow leaves, the more I slosh on the water. Killing them with kindness. I thank you; my plants thank you.

  2. I have some kind of tropical indoor tree, have never been able to find out the name of it, but it grows rapidly and is really a nice showy plant, it never blooms , it has grows large branches with many gagged shiny green leaves and as I say, when it was healthy it grows rapidly, my problem is that all of a sudden it started getting spots on the leaves, kind of pitty looking, then soon the whole branch just wilts and falls off, the plant continues to grow as fast as ever but it continues to debranch itself…I finally cut it all down put in new soil and started some new onen, the new ones grew but have the same problem as the adult, the adult keeps shooting out new branches but they still keep falling off, I have inspected for some kind of bug but there is nothing on this plant, the roots looked good when I repotted, no sign of rot or worms, just about ready to give up on it, but it is so pretty when it is healthy, and I have had this plant for about 5 years, this started last summer? any ideas for me to try ? thank you. Kare in northern Canada ( thats where it is an indoor tree.)

  3. i have a tropical plant that is about 4 ft. high,it has beautiful green leaves. then it grew a stem out of the top with seeds and little leaves,they are dying..the seeds are there…should i cut this off, not sure what to do,,,i think if i dont cut it it wont any taller,,,,hope u can help linda in indy….

  4. I have a white powdery stuff on my leaves.I have tried the neemoil and it keeps coming back..What do I do? Also I have an unbrella tree and I would like to cut it back so it all grows the same heighth what do I do?

  5. My plant has black spots on certain leaves and it’s spreading to the other ones

  6. I have variegated peperomia, looks healthy it’s growing but leggy. Is that supposed to grow that way?

  7. Hi – I have developed pin head size hard white raised up dots on the tops of my large cactus – any ideas ? Will it hurt or kill the cactus ?

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.