Using water to successfully grow houseplants
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My observation has been that the most common reason for houseplant failure is improper watering. This could mean watering too much (most common), watering too little, pots that don’t drain, or harmful chemicals in the water.
Use pots that have drainage holes. Roots need both water and oxygen to grow. A pebble tray protects furniture from overflow and allows the water to evaporate, increasing the humidity right around the plant, but doesn’t allow the pot to sit in the water.
If you use decorative pots that have no drainage holes, put the plant in a pot that drains and insert that pot into the decorative pot, making sure it will sit above any excess water, or pour out the excess water.
The salt in soft water is bad for most plants. City water should be left in an open container for a day so the chlorine can dissipate.
Wet entire root ball
Every time you water, wet the entire root zone. Water enough, from the top, that a little bit will run out the bottom of the pot, reducing salt build-up in the soil.
If the water runs right through the pot, you may need to water in such a way that the water has to go through the soil, rather than run out to the side and down the edge. Another option would be to set the pot in a sink or bucket full of water until there are no bubbles (just a few minutes), then pull it out of the water to drain away the excess. Once the excess water stops dripping from the pot, you can put the plant back in its normal place.
Watering on a schedule is not a good option because optimum frequency is based on plant requirements, plant location, humidity, type of pot, potting soil, temperature and season. Plants that are farther away from the light will use less water. During the winter season plants will use less water.
The best way to determine when to water is to feel the soil. I like to use the ½”, 1” and 2” measurements. Plants that are flowering should usually be kept evenly moist (dry to ½ inch). Succulents and cacti usually do best with less frequent water (dry to 2 inches).
This table will help with some of the more common houseplants.
This University of Georgia Extension publication has a more complete list of houseplants and their requirements: https://extension.uga.edu/publications/detail.html?number=B1318&title=Growing%20Indoor%20Plants%20with%20Success
Remember, every time you water, water thoroughly, just change the time between waterings depending on the needs of the plant. It is usually better to err on the side of dry rather than on the side of wet.