Houseplant Care – Evaluating Your Environment

Picking the right plants for your environment is one of the best ways to insure success when it comes to keeping houseplants.

Evaluating Environment - Do you Have What it Takes to Grow Houseplants

Good houseplant care starts with planning before you ever bring a houseplant home, and understanding your proposed plant spot will give you the information you need to pick the right plants.

What is a Microclimate?

Microclimate is a term often used to describe a mini-environment within a larger one. The environment around your radiator will be dryer in winter when the heat is blasting than the environment in your laundry room after you've just washed your bedspread.

The area where you will be keeping plants has a microclimate too, and the three simple tests below will help you understand the microclimate in your plant spot better.

Light and the Shadow Puppet Test

Light is important because it gives plants the energy to process many of the other things they need. You can tell what type of light your plant spot has to offer by doing a simple test. Pick a day with average light for the room and create a shadow puppet with your hand against a light background. If you can't find a light enough background in the room, use a piece of typing paper. Kids are great for this, and it’s a good way to get them interested in plants.

Now evaluate the quality of the light in your proposed plant spot. Rate your spot bright, medium or low light.

Temperature Test

Check your proposed spot for temperature hazards, like nearby vents, heaters and exterior doors that might create hot or cold spots. Select locations that maintain a consistent temperature and are near good light sources but aren't so close to windows that they might be subject to seasonal temperature fluctuations. You can use an inexpensive room thermometer to help you with your temperature measurements.

Humidity Test

Place an empty drinking glass in the freezer for fifteen minutes. Now place it in the area you want to test for humidity. Is it fogging up quite a bit? If so, the room is humid. If you can only detect a little frost on the glass, you can conclude you have average humidity, and if you don't see any condensation, the air is dry.

You should perform this test during three of the four seasons of the year because your home's humidity will vary depending on the conditions outside and your use of heaters, air conditioning, humidifiers, fans and other appliances.

Evaluating Your Test Results

Use the results of the light, temperature and humidity tests to decide where to place your plants, and what types of plants to choose. Without environmental helpers, your microclimate will be very important in determining which plants you will be able to keep successfully. Keeping houseplants is much easier when you select plants that are compatible with your environment.

Picking the Right Houseplant For You

Now that you have the facts about your environment, you will be in a much better position to pick the best plants for your needs, and that means success.

Understanding Toxic Houseplants

There is a huge interest in understanding which houseplants are toxic and what type of threat a particular plant represents.

The more sites you visit in order to come up with a reliable list of houseplants to avoid, the more evident it is that no one seems to agree.

Why Poisonous Houseplant Identification Is So Difficult

Plants have defense mechanisms, and more often than not, a plant will have some sort of hedge against predation. Evaluating the risk posed by the particular mechanism the plant uses can be very hard to do because a plant that might be toxic to a bird, may present few, if any problems to a bunny. A plant like pothos that may just make your kitten vomit, might cause lasting damage to your elderly cat.

There are lots of plants that present interaction problems. Chrysanthemums are notorious for causing contact dermatitis in many people. They are the bane of florists everywhere. Even plants like aloe vera, which is used in teas and many topical skin preparations, has a substance close to the exterior skin of the plant that is toxic.

The best practice when dealing with any decorative indoor or outdoor plants is to handle it with care. Indoor plants should be kept out of reach of children or animals who might ingest them out of ignorance or curiosity. Not every plant will kill when ingested, but even mildly toxic plants may cause increased allergic reactions in some susceptible people.

I've written the following articles to give you some guidelines when dealing with houseplant hazards:

Poisonous Houseplants
Child and Pet Safe Houseplants
Avoid Poisonous Houseplants
Be Prepared for a Plant Poisoning Emergency
Treating Allergic Reactions to Houseplants

Which Houseplants are Best for Controlling Air Pollution?

In the 1980s, tests conducted by NASA revealed that some plants have a huge impact on indoor air quality. Over a period of two years, plants were tested for their ability to filter Benzene, Trichloroethylene and Formaldehyde, common chemicals found in buildings. The choice of plants wasn't random. Houseplants were of particular interest because of the efficient way they absorb gasses necessary for photosynthesis. A side benefit of their increased gas processing ability is that houseplants also absorb chemicals that are harmful to humans.
The plants below all tested high for reducing air pollution. It's also likely that there are many other efficient air-cleaning houseplants out there that haven't been tested yet.


Snake Plant (Sansevieria trifasciata)

Heartleaf Philodendron (Philodendron scandens)

Elephant Ear Philodendron (Philodendron domesticum)

Cornstalk Dracaena (Dracaena fragrans)

Spider Plant (Chlorophytum comosum)

Philodendron (Philodendron selloum)

Warneck Dracaena (Dracaena deremensis)

Weeping Fig (Ficus benjamina)

Pothos (Epipiremnum aureum)

Peace Lily (Spathiphyllum)

Chinese Evergreen (Aglaonema modestum)

"Janet Craig" Dracaena (Dracaena deremensis)

Bamboo Palm (Chamaedorea sefritzii)

Red-edged Dracaena (Dracaena marginata)

English Ivy (Hedera helix)

Why does my houseplant have yellow leaves?

This sounds like an easy question to answer, but yellowing leaves can be caused by a number of different problems. The three most common are over watering, pot bound roots, and inadequate light.

To diagnose the problem yourself, become a bit of a detective.

Over Watering

Root rot from over watering is one of the biggest reasons for yellowing leaves on houseplants. If you've discovered that your plant has been sitting in water, or your plant's pot has no drainage hole, root rot is a likely cause for yellowing leaves and drooping stems.

Once started, roots rot quickly, and a plant is in jeopardy of starving to death of it doesn't get help before too much of its root structure is destroyed. If you suspect root rot, remove your plant from its pot and inspect the roots. Remove any decayed, blackened or mushy roots and replant the remaining root ball in new potting soil. Make sure to use a pot with a drainage hole. It will also help to fill the bottom of the pot with broken pottery, pebbles, or marbles to insure good drainage.

Your plant is probably in shock and will take some time to recover. Trim yellowed foliage, and only water your plant when it is dry. Test the dirt by poking your finger about an inch into the soil. Only water if your finger is dry. Don't fertilizer your plant while it is recovering. Keep it out of drafts and away from temperature fluctuations.

Pot Bound Roots

Check the bottom of your plant's pot to see if its roots are straggling out of the drainage hole. If they are, then your plant needs to be repotted, and lack of water and nutrition are probably the reason its leaves are turning yellow. When you remove your plant's pot, you should see roots circling the soil like loops of twine. This is a sure sign that the plant is root bound. Disturb the roots by tearing a few of them to train them outward, and repot your plant with a quality potting soil appropriate for it. Select a new pot that is a couple of inches larger than the old one.

Inadequate Light

If you can't see roots trailing out of the drainage hole of your plant's pot, and you think its roots are in good shape, check a description of the plant variety and make sure your are giving your plant adequate light. If you are not, then move your plant closer to a window, or into another room.