The origin of the oyas is mysterious as to when and where they appeared. They would have appeared in China or in the Roman Empire, about 2000 years ago. Lately, these terracotta pots have met with real success for their efficiency and ecological aspect.
Oya is one of the few techniques for regular watering. This is underground irrigation through a terracotta pot filled with water. In fact, this pot was imagined and created in a very clever way and has porous properties. You bury the pot in the soil near the plant you want to water, then fill it with water, and put the lid on. The water inside the pot will escape thanks to the porosity of the terracotta. The micro-droplets that come out will water the plant very slowly, but sufficiently. Once the pot is emptied, it is refilled and so on.
This invention has very interesting aspects. For example, this slow and regular watering stops when the soil is moist enough because the plant and the pot are self-regulating. The plant takes just enough to hydrate. The pot, on the other hand, delivers the right amount, and once the soil is sufficiently watered, it stops releasing the droplets. This slow and regulated watering allows the plant to manage its water needs on its own. This also helps to compensate for watering oversights and provides the plant with an optimal water supply.
An old technique brought up to date
The use of terracotta pots to supply crops with water is an ancient watering technique that aimed to save water. In this period of drought and the fight against global warming, this method could well regain all its usefulness and effectiveness.
While some people tend to overwater their plants, which can cause water stress, oyas help control and prevent this problem by continually providing them with just the right amount of water.