Choosing a Container for Houseplants
by Don Janssen, Extension Educator
If your houseplants have outgrown their pots itís time to gather up the potting soil and some new containers and give these plants new homes.
Often the container is the key to success with a plant and thatís related to its size, its porosity, and the presence (or absence) of drainage holes in the bottom. If your aim is to provide a good growing environment for your plants, these are important in the choice of a plant pot.
All of these characteristics are related to watering, often the key element in whether a plant lives or dies indoors. Winter is a particularly tricky time for watering because plants arenít growing much and arenít using much water.
Pot size is more than an aesthetic consideration. A large plant in a too-small container dries out quickly. Thatís one indication that a plant needs repotting. A small plant in an overlarge container not only looks lost in it but may suffer from too much water because, after watering, the relatively large volume of soil stays saturated for a long time.
The porosity of a container affects how quickly the soil dries out after watering. The humble clay pot is porous -- air moves into the soil and water moves out through the sides of the pot. Glass, glazed clay and plastic are impervious. Clay is the best choice for cacti and succulents and any plants that donít tolerate wet soil for long periods.
Why all the concern about water? Because plant roots need air as well as water to function. Roots that remain in waterlogged soil for long periods tend to rot and die. Plants wilt as if they are dry, but more water is the last thing they need.
The third key factor is a drainage hole in the bottom of the container. Drainage holes permit excess water to escape.
Another advantage of drainage holes in the bottom of a container is that it provides the option of watering from the bottom. This is important with plants such as cyclamen, which doesnít tolerate water in its crown, and African violets, whose leaves are sensitive to cold water splashed on them.
Whether you water from the bottom or the top, itís important to empty any water left standing in the saucer after the soil is thoroughly moistened. If the pot is left sitting in water, the soil will keep taking up water as fast as itís lost to evaporation or taken up by plant roots, and the spaces between soil particles will remain filled with water rather than air.
Using clay pots with drainage holes and saucers is no guarantee that you wonít kill your plants with too much water but especially if you know that you tend to overwater, clay would be your best choice. If you want the decorative look of glazed ceramic pots, simply place the porous pot inside the fancy container. A layer of non-absorbent marbles, pebbles or similar material placed in the bottom of the fancy outer pot will keep the plant from sitting in water that runs out of the inner one.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office