The Ancient Roots of Soil-Free Farming: The Hanging Gardens of Babylon

A Peak Into History

Hydroponics—the art of growing plants without soil—has become a cornerstone of modern sustainable agriculture.

While hydroponics is often hailed as a modern innovation, its fundamental principles have ancient origins, deeply rooted in the agricultural practices of early civilizations.

Long before the scientific development of hydroponic systems in the 20th century, ancient cultures were experimenting with water-based farming methods. From the legendary Hanging Gardens of Babylon to the irrigated rice paddies of China, civilizations across the globe recognized the power of water as a vital resource for nurturing plant life. These early techniques—while not hydroponic in the technical sense—were based on the same core idea that plants can thrive in water if provided with the right nutrients.

The Hanging Gardens of Babylon: A Legend of Early Hydroponics

One of the earliest and most famous examples of water-based agriculture comes from ancient Babylon around 600 BCE. The Hanging Gardens of Babylon, one of the Seven Wonders of the Ancient World, are said to have been an awe-inspiring feat of engineering.

According to ancient accounts, the Hanging Gardens were a magnificent series of terraced gardens, believed to have been constructed by the Babylonian king Nebuchadnezzar II (reigned 605–562 BCE) for his wife, Amytis of Media, who longed for the green hills and gardens of her homeland. The gardens were reputed to have been an engineering marvel, featuring a series of tiered platforms with lush vegetation, flowing water, and a variety of trees, shrubs, and flowers.

The term "hanging" is somewhat misleading, as the gardens may not have actually "hung" in the way modern readers might imagine. Instead, they were probably built on massive, multi-level terraces, creating the appearance of a floating garden. These terraces were believed to have been supported by stone columns, with water being lifted from the Euphrates River through an advanced irrigation system, possibly using a screw-like mechanism called the Archimedean screw, or by other forms of hydraulic engineering.

How Did the Hanging Gardens Work?

Despite the lack of direct archaeological evidence confirming the gardens' existence, ancient texts describe a sophisticated irrigation system that made the gardens thrive. Here's a breakdown of how the Hanging Gardens might have functioned:

Terraced Structure:

The gardens were likely constructed in multiple levels, or terraces, which were stacked on top of each other. These terraces would have been supported by massive stone walls, creating a stepped effect. Each level would have been filled with soil and planted with trees, shrubs, and flowers, providing a lush and visually stunning landscape.

• Some accounts suggest that the terraces were supported by stone pillars or columns, which would have allowed for a strong structure while also creating an open space beneath each layer.

• These terraces would have been about 25 to 30 feet (7.5 to 9 meters) high, possibly as many as seven levels, with each level containing a variety of plants.

Irrigation System:

The most impressive feature of the Hanging Gardens was their irrigation system, which was likely essential to their survival, especially in the arid climate of Babylon, where water was not readily available.

• The ancient Greek historian Strabo and the engineer Philo of Byzantium describe the gardens as having a complex irrigation system that involved lifting water from the Euphrates River (which flowed near Babylon) to the upper terraces. This was likely done using a combination of screw-type pumps or chain pumps, technologies that were already in use at the time.

  • Archimedes’ Screw: One theory is that the gardens used a device similar to the Archimedean screw, which was a screw-shaped pump that could lift water from lower levels to higher ones. The screw would have been powered by animal labor or human effort.

  • Chain Pumps: Another possibility is the use of chain pumps, where buckets attached to a chain could lift water from the river up to the gardens, which would then distribute it through channels or irrigation systems to the plants on each level.

• The water would have been carried through a network of channels or conduits, often made of lead or clay, that brought it to the uppermost terraces and allowed it to trickle down to the lower levels.

Soil and Fertility:

To sustain the extensive plant life, the soil would have needed to be highly fertile. The soil on the terraces was likely a mixture of local earth, composted organic matter, and possibly decaying plants from the river’s banks. The fertility of the soil may have been enhanced by regular irrigation with nutrient-rich water from the river.

• The gardens would have hosted a variety of plants, including trees, shrubs, and flowers. Some accounts suggest that there were even fruit trees, which would have required large amounts of water and fertile soil to thrive.

Waterproofing:

One of the challenges in constructing such a high-rise garden would have been ensuring that the water didn’t seep out and damage the structure. Ancient sources like Strabo mention that the terraces were waterproofed using bitumen, a natural tar-like substance, or possibly lead. This would have been applied to the surfaces of the terraces to prevent water from leaking through and to direct it toward the plants.

• Bitumen or tar may have been spread between the layers of stone or clay, creating a waterproof barrier to help retain moisture in the soil.

Theories and Uncertainties

While many ancient texts describe the gardens in detail, their actual existence remains unclear. Some historians and archaeologists suggest the gardens may not have been in Babylon at all, but rather in Nineveh, the capital of the Assyrian Empire. This theory arises from confusion in ancient texts or misinterpretation of geographical descriptions.

• Some scholars also question whether the gardens were a physical structure or more of a symbolic or poetic description of Babylonian ingenuity and grandeur. If the gardens were real, their exact location, design, and the way they functioned may never be fully known.

Conclusion

The Hanging Gardens of Babylon, if they existed as described, represent one of the earliest and most ambitious attempts at controlled irrigation and urban gardening in the ancient world. The use of terraces, advanced irrigation systems, and fertile soil would have allowed for a highly sustainable and aesthetically pleasing agricultural system, bringing beauty and greenery to one of the most significant cities of the ancient world. Whether or not the gardens ever existed in the exact form described, they continue to captivate the imagination as an enduring symbol of ancient engineering and human ingenuity.