The Kratky System
The Kratky method is a passive hydroponic technique, where plants grow in netpots which are in contact with a reservoir of nutrient-rich water. As the plants grow, the water level of the reservoir will decline as plants absorb the water in the system, leaving a gap of the roots exposing to the air. The “air gap” is essential because it is where the plants respire. Due to this mechanism there is no electricity used as well as no pumps and wick needed. This makes the system very cheap and easy to maintain.
The Bottleponics-System is a form of vertical farming, where plants are grown in recycled plastic bottles which hang above each other. A few bottles are connected via small holes to allow water to run from the top to the bottom bottle. Many bottle towers of such kind are hung next to each other and connected to an upper and lower pipe. The pipes supply the bottle towers with water from the reservoir which is placed next to the system. As this is a circulating system, the circulation of water is maintained by means of a pump or by hand with buckets. Small windows are cut into the bottles to allow sunlight and oxygen to reach the plants and enhance their growth.