This article looks at the work the author has done regarding hydroponics.

The term hydroponics refers to the growing of plants suspended in water rather than growing them in the soil. Hydroponics have an ancient origins with the Babylonians using such system but the modern science of hydroponics began in 1936 with Dr. W. E. Gericke at the University of California.

Various methods exist for suspending the plants and a water including the use of sand expanded clay pellets, rock wool, or even just holding the plant's roots suspended in a thin film of water. The system uses the water to circulate the nutrients. Variations of hydroponics include airoponics where the plant roots end up suspended in a mist of nutrient solution.

The basic hydroponic system consists of the plants to grow, means to suspend those plants and a nutrient solution. The nutrient solution provides all the nutrients a plant needs to grow. Normally the plant would obtain these nutrients from the soil it grows in. In a hydroponic system nutrients get supplied in a liquid solution.

For experimentation, three system the author investigated three systems:

1. Gravity feed based system
2. Pump based system
3. Modified, modularised, pump based system

All systems used hy-pro A+B hydroponics soklution. % ml of each added to about 5 liters of water once a week, except durring germination when the authors used halt the ammount (2.5 ml of each per week)

Method

Gravity Feed System

As a future sustainable, post carbon, socioeconomic might wish to minimise its energy utilisation due to  a declines in one of the major energy sources currently used (oil), investigation first concentred on a system the required minimum energy input; a gravity based system.

The system consisted of a support medium for the plans (expanded clay pellets) an a reservoir that drained slowly under the influence of gravity. A large plastic bottle turned upside down with a hole in the top formed the reservoir. The liquid containing the nutrients would then leak out supplying the plants as needed. A large container then held the plants, with the support medium, and reservoir.

This system grew onions and lettuce.

Pump Bases System


 

Figure1: The above picture shows the basic pump based system. The red bucket holds the clay pellets and forms the area where the plants grow. The other bucket always the reservoir which houses the pump and a nutrient solution. The tubes in between allow pumping of the liquid around the system, one connected to the pump that then goes to the top of the red bucket. The other tube and acts as a drain allowing the nutrient solution to return to the reservoir.

The pump based system consisted of a bucket container with the same support medium as the gravity feed system but did not use the same reservoir system. Instead, a bucket to the side of the main container acted as reservoir. The bucket also contained a water pump that pumped the nutrients to the top of the main container through a tube. A second tube at the base of the container allowed the nutrient solution to drain back to the reservoir.

This system grew lettuce.

Figure 2: In the above picture you can see the end result, iceberg lettuce grown in a hydroponic system. You can also see one problem encountered; the black mould the has grown in a tubes. Future systems probably would benefit from having tubes that did not allow light in.

Modified, Modularised, Pump Based System



Figure 3. The above pictures show the modulused system.

The final system formed a modification of the previous system in that a number of smaller containers replaced the single bucket container and the system used a more powerful pump. The system had a modular nature in that the operators could plug in or remove containers as needed. The system under experimentation used three container and grew lettuce, tomato and beans.

Figure 4. The results! Tomatoes growing in the system.

Conclusion

Hydroponics systems can offer a way to grow food in alternative situations to conventional farming such as in vertical farming. They do however, has some drawbacks. They do have an energy intensive nature and require the production of nutrients to feed the plants. Future work could look at organic nutrients solutions, perhaps drive from fish waste or worm composting, and the use of renewable energy such as wind to drive the pump.

References

Sutherland, Dr. Sturan, “Hydroponics for Everyone”. Hyland House. 2003.  ISBN 186447069-0