Guide to Stoneware Pottery
If you are looking for reliable glazed or unglazed flowerpots for your garden the best choice is stoneware pottery, as it has the clay-body necessary to endure a variety of temperature conditions and it is impervious to frost or as they say in the trade, “Frost Resistant.” The strength of this clay-body and the firing temperature is what makes it so ideal for gardening projects. You may have noticed with terracotta pots that over a period of years, the clay-body begins to breakdown and deteriorate. This is due in part to the clay used and the low firing temperature. Not so with stoneware. As plants and or trees grow inside the pottery, a lesser clay-body will more likely fail or crack as the roots push against the outer walls. Also, in the winter months in colder climates, when the moisture freezes and expands it too will push against the pottery walls and cause cracks. The density of the stoneware clay and the temperature of the firing vitrify the clay and make it moisture difficult to penetrate the body and therefore results in a stronger more durable quality.
Stoneware pots are manufactured in a wide array of styles from Dragon Kilns that have been around for centuries and produce a more rustic pottery look with more variance in the color with generally less consistency from piece to piece as they are positioned within the kiln to Tunnel kilns which use a more precise manufacturing technique utilizing gas to create a very predictable glazed pottery with even more consistent color. In the case of a tunnel kiln, the pots flow through a stable temperature and are all fired equally and the pottery is less affected by the location within the kiln.
Neither technique is necessarily better, it all depends on the requirement of your given project. Some people prefer the more random and less controlled features that a dragon kiln fired pot produces while others want a controlled and consistent color for using multiple pieces throughout their project or space to achieve a consistent look.