Choosing a pot is one of the most important decisions anyone interested in indoor gardening has to consider.
Even when plants are bought already in the container, making it seem as if the choice has been made for you, you need to consider whether that plant will thrive in that pot.
You also need to consider, just as you would with plants grown yourself from seed or cuttings when to re-pot. That decision will be influenced by the container you select at the outset.
Apart from subjective issues like color and material, which come into play in decoration designs, size is an important criterion to think about. Size will play a role in decoration plans, but it’s chiefly a matter of repotting.
Most houseplants will require repotting every couple of years. That varies depending on the initial size, the species, the amount of sunlight and other factors. But as an average, it’s reasonable.
A large pot, for example encourages free root growth, and usually provides substantial soil nutrients for them to draw on. Thus, starting with a larger pot will allow the plant to grow faster, leading to quicker repotting. But it can lead to excess water retention, so don’t go overboard.
A smaller pot provides less soil to absorb nutrients but can lead to a higher concentration. While there’s less room to grow, a smaller pot constrains root growth and the plant grows more slowly.
These two effects tend to offset one another, leading to about the same amount of time to repot for a given species. But it’s important to take care not to allow the plant to become root bound. Again, aim for the middle ground.
When repotting is required, the pot size will need to be increased about 1-2 inches in diameter to allow for continued healthy growth.
Drainage is an equally important consideration.
Some professional sources estimate that as many as 90% of indoor plants are overwatered, many of them receiving a premature death as a result. Diseases are more likely and more frequent, and often more severe, as a result of excessive soil moisture. Most harmful organisms need a moist environment to thrive. Mold, mildew and fungi are obvious cases.
Herbs are a prime example of plants that can too easily be overwatered. Most evolved in poor, rocky soil and lots of hot sunshine. They flourish in conditions that would stress other plants and require very little water.
Bonsai, though most enjoy a moist soil, still need plenty of drainage in order to ensure that they are not ’sitting in water’ all the time.
That implies: choose a pot with plenty of holes in the bottom. Keep the holes to a modest size in order to prevent soil spilling out or cover them with small mesh. But neither should they be too small, since they’ll become too easily plugged.
To test what size is about right, place a saucer under the pot and fill it to about 1/3 full with water. Repeat until the water is no longer taken up by capillary action into the soil above.
Keep track of the volume of water you used. That will give you a measure of the right sized holes for that type of plant and soil, as well as the amount of water to use. With this technique you can measure drainage and watering amount and frequency in one experiment.
Most people choose a pot based on appearance, which is an important factor since you want your home to look nice. But consider the plant’s needs, too, since it’s a major part of the decorating scheme.