Cultivating crops without the use of soil

Recently Merlin undertook a bus journey that happened to pass along a main road through one of the less salubrious areas of a large industrial city not far from my home territory. The district is known to be something of a crime hotspot and is certainly not an area to walk through at night.

As the bus drew up at a traffic light, Merlin was surprised to see a small industrial unit with a freshly painted sign indicating that the company within the unit offered for sale all manner of equipment for hydroponics.  

Hydroponics is a method of soil-less culture for plants, in which the plant roots are anchored in an inert substrate and flooded with a nutrient-rich solution. The principle is ancient. Indeed, the Hanging Gardens of Babylon, one of the seven wonders of the ancient world, are reputed to have used an early form of hydroponics to cultivate plants.

In the late 1920s and early 1930s the plant physiologist William F. Gericke of the University of California extended his research into plant nutrition to look at the practicality of growing crops commercially using soil-less culture. He it was who coined the name “hydroponics”.

During the 1939–45 war the shipping of fresh vegetables overseas was not practical. Also, many of the remote islands where troops were stationed were not places where vegetables could be grown in soil.

Hydroponic technology was therefore tested as a means of providing fresh vegetables. In 1945, the US Air Force built one of the first large hydroponic farms on Ascension Island in the South Atlantic This was followed by additional hydroponic farms on the islands of Iwo Jima and Okinawa in the Pacific. Crushed volcanic rock or gravel was used as the growing medium. By 1952 the US Army’s special hydroponics branch was growing more than eight millions pounds of fresh produce each year.

Hydroponics as a method of growing vegetables commercially is relatively rare in the UK. However, this year the UK’s largest ever greenhouse system, Thanet Earth on the Isle of Thanet, started producing salad vegetables using hydroponics. There are five huge greenhouses and the whole site, including the packing station, occupies some 91 hectares.

Thanet Earth currently supplies some 2.5 million tomatoes, 700,000 peppers and half a million cucumbers each week to the major supermarkets.

And why was Merlin surprised to see, in an inner city area, a warehouse selling equipment for hydroponics? Could it have any connection with the practice of growing cannabis in back bedrooms.