Gardening in containers has made the pleasures of a garden widely available to those who do not have land to tend. Planters can be placed on balconies, decks, patios, porches and steps, bringing living plants into an amazing variety of areas. While plants can be grown in just about any kind of container, clay and plastic planters are popular choices. Both types of planter are readily available, fairly inexpensive and easy to use.
All growing containers need good drainage, because root rot is a danger for plants with roots left in very wet conditions. Most planters have adequate drainage holes in the bottom. Occasionally, however, the gardener must enlarge the holes or drill new ones. This is easier with plastic planters.
Water and Evaporation
Soil dries out faster in a planter than it does on the ground, so plants in containers require more frequent watering. Clay planters usually dry out faster than thick plastic planters, but sometimes not as fast as thin, lightweight plastic pots. A glazed clay planter will dry out more slowly then an unglazed one. When filling a clay or terracotta planter for the first time, soak the pot thoroughly before filling it with soil, so that it does not draw moisture away from the newly transplanted plants.
Plants do not grow well in airless conditions; this is why gardeners prepare the soil, making it loose and light, before they plant in it. Clay planters allow better air movement than plastic planters. Both kinds of planters can be placed on small 'feet' to encourage air movement around the bottom of the pot.
Clay planters are undeniably heavier than plastic planters. This is a disadvantage if the planter is large and must be moved. It is an advantage in windy conditions or during storms, since the heavier planter is less likely to be blown over.
Heavier planters are also less likely to be knocked over by garden pests. If the planter will be placed on a balcony, deck, or other structure, it must not be too heavy for the structure to support. Keep in mind that a pot filled with wet soil is much heavier than a pot with dry soil.
Clay planters are likely to crack and break during heavy frosts and freezes, so they are generally stored in a shed during the winter, unless the climate is very warm. A new kind of terracotta planter is being marketed as 'frost resistant', which may reduce the problem. Heavy plastic planters are seldom damaged by winter weather, but lightweight ones may shatter.
Personal preference is the only basis for judging the beauty of clay and plastic planters. Some people find the patina that develops on clay planters over time appealing, while others find it distasteful. Some people find brightly colored plastic planters charming, while others find them garish. Choose what you find most attractive for your own garden.