Our mission is to share the wonders of the natural world by publishing books from experts in the fields of gardening, horticulture, and natural history. Grow with us.

Ten Common Houseplant Problems

by Timber Press on November 28, 2014

in Gardening

This guest post was written by David Deardorff and Kathryn Wadsworth, authors of What’s Wrong with My Plant?, and originally appeared on their blog.

10 Common Houseplant Problems

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.

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.

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.

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.

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

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.

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.

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

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.


{ 4 comments… read them below or add one }

1 Carlton Monopoli December 15, 2011 at 11:36 pm

Spot on with this write-up, I actually suppose this internet internet site needs rather more consideration. most likely be once more to learn considerably much more, thanks for that information.

2 Sara November 5, 2014 at 7:21 am

hi there,
One of our house plant is ill, I think. The leaves are very sticky, and we can feel it on the floor around the pot. We diluted dishwasher soap with water and sprayed on the leaves, but it didn’t work?
Do you know what happen? We don’t want to kill the plant, but we don’t know what to do, any suggestion?

3 Brian Ridder November 5, 2014 at 10:51 am

Hi Sara,
What kind of plant is it? Do you have a current picture you can post?

4 Cheryl November 1, 2017 at 10:41 pm

I have 2 Ficus Alli that until a few days ago seemed to be doing great. Now I notice extreme leaf loss, center branches drying up and are both covered in white spot. I used my flashlight to check for spider mites and scales but didn’t see any. Can someone help me

Leave a Comment

{ 1 trackback }

Previous post:

Next post: