Last Updated on December 29, 2021 by Grow with Bovees
Everyone loves a nice plant pot, but which type should you choose – a terracotta one or something made from another type of clay?
We’re going to take a closer look at these two types of pots to find out what the differences are and which is best to use as planters for the home and garden.
What is a Terracotta Pot?
Taken from the Italian term ‘terra-cotta’, which literally means “Baked Earth”, the word terracotta nowadays is most often used to describe a type of earthenware clay pot made from organic clay fired at a low temperature of between roughly 1000 and 1100 degrees Celcius.
Terracotta is also often used as the term for a specific type of earthenware porous clay material that has a high iron oxide content which gives it the distinctive reddish-brown color. The term is commonly used to describe this color as well.
Besides the usual spelling we’re familiar with, the term can also be written as terra cotta or terra-cotta pots.
The Latin term the name derives from is ‘Terra Cocta’.
When this type of clay is fired, it remains quite porous and will absorb water unless glazed or mixed with other ingredients to make it more waterproof. If you experience any mold on terra cotta pots, then we can show you how to fix that.
What is a Clay Pot?
When we talk about a clay pot we are referring to a type of pot that has been made from a different type of ceramic clay to terra cotta pots and has been fired at much higher temperatures.
The combination of a different clay that contains more glass-forming materials than terracotta and the higher temperatures mean that the pot is a lot less porous due to the vitrification process during baking.
These types of containers are often glazed to make them fully waterproof, and the finished products are decorated with different designs and colors.
What is Terracotta Clay Made Of?
Terracotta, or earthenware, is an organic clay rich in many impurities and contaminants, the main one being iron oxide or iron ore, and is very often used as clay in pottery projects.
When this type of clay is fired, the high iron content interacts with the oxygen inside the kiln and creates that iconic red color clay pot that’s easy to recognize.
Not all clay terracotta products are red though, some are buff-colored or grey when unfired. Most are red-burning though, meaning that the baked clay turns a red or orange-brown color when fired.
There are some fired terra-cotta clay pots however that have a distinct brown or pink hue when fired.
The iron the clay contains doesn’t just affect the color of the clay, it also affects the temperature it can tolerate in the kiln as it acts as a flux.
Flux lowers the melting point of a mixture of materials and clay contains ingredients like silica that form glass when they melt.
Glass fills up the spaces between the clay particles and as it cools this enables the fired clay to become less porous. This is what we mean when we talk about the vitrification process.
This part of the melting process is very desirable, but all clay has a point at which the whole lot will melt if it becomes too hot and this point varies between the different types of clay.
As terracotta clays contain a lot of iron and other fluxing ingredients, they melt at a lower temperature than other accessible clay like porcelain or stoneware.
Other Forms of Clay Used for Pots
Besides earthenware, the other well-known types of organic clay are stoneware clay and kaolin.
Clay pots used for planting and garden use are usually made from a raw material of stoneware which is fired at a higher temperature than an earthen clay pot.
In its raw form stoneware clay is typically grey in color and when baked in a kiln at between 2100 and 2300 degrees Fahrenheit, changes to a more medium-grey or brown.
After firing, the hardened clay product takes on a very dense, hard form that is stone-like and non-porous, making it ideal for use outside, or as tableware and clay cookware.
Another material commonly used for clay vessels is porcelain clay which is a mixture of kaolinite clay, feldspar and quartz and fired at very high temperatures to create a highly durable material that is used for more decorative pots and artistic ceramics.
All the natural clay used for plant pots requires high temperatures in a kiln to mature, unlike modern air-dried or non-firing clay used for dry clay sculptures or polymer clay.
Is Clay or Terracotta Better for Plants?
Both clay pots and terra-cotta pots are great for use as planters. Terracotta pots absorb water and allow air to circulate around the roots, so they are best for plants as dracaena marginata, that prefer well-drained soil.
Clay pots are not porous, allowing the soil to retain the water, so many gardeners prefer clay pots for plants that need to be kept well watered with damp or moist soil.
FAQs
What is the Difference Between Clay and Terracotta Pots
The main difference between terracotta and clay pots, as we are defining them here, is that they are made from differing types of clay that give them different characteristics.
Terracotta pots have a reddish-brown color, are usually not glazed, and are permeable. Clay pots are usually glazed and decorated, plus they do not absorb water.
Are Terra cotta Pots Clay?
Yes, terracotta pots are clay as they are made from earthenware which is a type of organic clay.
Once the earthenware clay has been molded into shape and fired into red earthen pots, it becomes known as terra-cotta, a term taken from the Latin ‘Terra Cocta’ which translates as ‘Baked Earth’.
Do You Have to Presoak Terracotta?
It’s very important to pre-soak terracotta pots before filling them with soil and planting out your plants.
Otherwise, the porous nature of the pot will allow it to absorb the moisture from the soil, causing it to dry out very quickly, which is not great for new or young plants which need plenty of water.
Resources;
https://www.britannica.com/art/terra-cotta
https://www.sciencedirect.com/science/article/abs/pii/S0045653503001899