Watering:

More houseplants die from overwatering than anything else. Most houseplants like to dry out between waterings.  Some can dry out a lot (snake plants) some moderately (pothos, philodendron, dracaena canes), and some just a little (peace lily).  So how do you know when that is achieved?  There are several ways you can gauge this, and it’s best to combine all the methods until you have a good schedule established:

• Take note of how heavy the pot feels once watered completely (water just begins to come out of the holes in the bottom). It should feel significantly lighter when dry, and somewhere in between for moderate drying. Check it every day for a new plant or newly potted plant.
• Water the plant completely and measure the time until you see it just barely wilt. Note that this is not effective for plants with very thick leaves like snake plants and rubber plants. For some thicker leaved plants you will see that the leaves hang lower on the plant, but the individual leaf doesn’t appear wilted. Water it completely, and next time water 1 to 2 days before your established “wilting” point.
• Use a chop stick to see how wet it is at the bottom. Place the chopstick all the way down in the pot and wait a few seconds.  You should see the moisture line, like an oil dipstick.  Plants that want to dry completely will want this very low, moderately in the middle, and slightly about ½ to 1 inch for a 6 inch pot.
• If you’re not sure it’s time to water, wait a day and check again.
• Few large houseplants will need watering more than once a week. 6 inch pots may need twice a week, depending on the individual plant and room temperature.
• Water sitting in saucers should be drained after no more than 10 to 15 minutes.
• CUT BACK ON WATERING IN WINTER. This is a resting time for most houseplants, and you’ll find that you may need to water only half as much.
• Plants in low light will need significantly less water than plants in bright light. With less light, they’re not growing much so can be easily overwatered.  Imagine them as couch potatoes-- they’re not expending much energy, so they need to cut back on the food and drink!
• If after a long period you find that your plant is needing water more frequently, this may be a sign that the roots have filled the pot and it needs more room.

Soil:

• Use container potting mix for indoor plants ONLY.  A soilless mix is imperative so that the plant will drain well. 
• Containers MUST have holes for drainage, unless it is an aquatic plant.

Roots/Repotting:

• Never go up too big when repotting. Doing so leaves too much soil where no roots exist, so the water will never be taken up properly and the plant will rot.  Usually one inch larger than the old pot is the rule.  If you don’t want to keep buying new fancy pots, pot in a nursery pot and place inside the fancy pot.  If you don’t want to see the nursery pot inside, cover the inside top with preserved sphagnum or Spanish moss, but don’t let it touch the stems.
• When you get a new plant, it’s always a good idea to pop the pot off and take a loot at the root system.  If the roots are small (or heaven forbid brown, mushy and water-soaked), and you have a lot of loose dirt at the bottom or sides, take extra care with watering.  If it’s really bad, consider repotting into a smaller pot more suited to the size of the root ball.  This may happen when growers “up-can” because the top growth is large, but push it out the door before the root system has a chance to catch up.  Not a good practice, but it happens more than you’d think.  I always check the roots before I buy ANY plant.  If the store objects, then you might want to reconsider shopping there.
• Repot at the beginning of the growing season when roots will be actively growing, usually spring or early summer. That will prevent the root ball sitting in a sheath of empty soil for too long, again preventing root rot.

Light:

• Most houseplants will burn in direct sunlight, as in their native haunts they are understory plants. Some plants than can take full sun are often grown in shade so that they are pre-acclimated to live indoors—some large ferns are crotons, for example.  If you purchased your plant outside, and the foliage looks clean and healthy, then it’s safe to go in the sun.  Plants should be gently acclimated over 1 to 2 weeks if their lighting is to be changed.
• Bright indirect light is direct sun through sheer curtains or an arc within 1 to 2 feet of a brightly lit window. Light does not travel sideways, so light is lower the same distance to the sides of a window compared to in front.
• Brightest light is an unobstructed south window, followed by east, west, and north. As the angle of the sun changes throughout the year, you may need to adjust the location so that direct sun doesn’t burn the leaves.  Angled sun later in the year is usually less hot so it may not be a problem.
• Remember to regularly rotate the plant for even growth.
• Bright fluorescent light is usually plenty for most low and medium light plants.
• Anything farther than 8 feet from a window without supplemental lighting is ill-suited for live plants for any length of time, but there are some very life-like imitations available, or you will need to rotate often (every week to 2 weeks).

Temperature:

• Most houseplants prefer temperatures between 55 and 85 degrees--they are tropical, after all!
• Best growth is usually acheived between 65 and 78 degrees for most house plants.
• Temperatures below 55 degrees for any amount of time, even a cold draft, may be enough to damage sensitive foliage.  This may take up to 10 days to manifest, and will usually be seen as brown spots with a water-soaked or greasy appearance.

Humidity:

• Most houseplants will appreciate more humidity than the average home in winter can supply--drying leaf tips on a properly watered plant may be an indication.  
• Grouping plants together will increase humidity.
• Placing pots, individually or grouped, on a saucer filled with pea pebbles and water will increase humidity as the water evaporates.  Note that the plants should be sitting ON the pebbles, not IN the water, so be sure the level of the pebbles is high enough.
• Place the plant pot inside a larger pot filled with wet sphagnum moss.  Keep the moss moist, but do not allow water to build up at the bottom.  As the moisure evaporates it will increase the humidity around the plant.  Be sure to keep the moss away from the plant stems.