Most house plants are native to warm, humid, rainy, shaded forests. Arizona, on the other hand, outside of monsoon season, has a very dry climate totally lacking in the humidity tropical plants need. This lack of humidity can cause leaf tips, and then leaf margins, to turn brown. Finally, bottom leaves will turn yellow and drop off. Extra watering and misting will not solve the problem.

There are ways to provide the humidity house plants require. They are:

1. Place house plants close together to form their own micro-climate.
2. Use a small, indoor, falling water sculpture nearby to provide humidity.
3. Fill a saucer, oversized for the pot, with fine gravel such as that used in fish aquariums. Place the pot on top of the gravel and fill the saucer with water to just below the bottom of the pot. The evaporation of water from the gravel will provide a cocoon of humidity around the plant. The saucer may need daily watering.
4. Place the plant pots in a large aquarium with a glass or plastic top that will retain moisture.
5. Keep plants away from vents and warm or cold drafts.
6. Locate house plants in a bathroom, laundry room or kitchen where the air will be briefly humid due to normal daily activities.

For a list of house plants and their humidity, water and lighting needs, see House Plants: Selection Criteria.

Fungus gnats are tiny flies that lay their eggs in the soil of potted house plants and become a nuisance inside the house.
To rid your potted plants of fungus gnats and their larvae:

1. Remove all dead plant debris from the pot because the larvae feed upon dead plant material.
2. Water with a solution of Bacillus Thuringiensis bacteria (Bt), an organic control for caterpillars used to kill insect larvae. Bt is safe to use around children and pets.
3. Or, drench the soil with pyrethrum, an organic pesticide made from dried chrysanthemum flowers.
4. Use sticky traps near infested plants to catch adult gnats.

Experiments using diatomaceous earth on top of potting soil have proven ineffective.