In order for a plant to grow and reach its full genetic potential, it is necessary to provide right amount of nutrients, water, and air at the right time. This is the very basis of farming. Hydroponics allows to provide the right proportion of these supplies at the right time, to grow plants indoor without having to worry about large scale infrastructural elements such as land, soil, irrigation and pest control. Simply put, hydroponics is growing plants with gravel, liquid or other medium with added nutrients but without soil. Roots are exposed directly to the nutrients solution, therefore offering a controlled environment in terms of what one feeds to the plant. It is possible to have a precise control over what you feed to the plant, as it is going to get directly absorbed by the roots.
I found this book extremely helpful in understanding the basics of hydroponics: http://www.agriculture.uz/filesarchive/HowToHydroponicsRobert2003.pdf
In general, a hydroponic system looks like this and has following fundamental elements:
- Container: Contains plants, nutrients solution, and pretty much defines the boundary of the system. It can be as small as a half gallon flask, or as big as 50 liter tank.
- Nutrient solution: A water based solution of nutrients, typically NPK (nitrogen- phosphorus- potassium) variant, depending on what kind of plants are grown.
- Flow mechanism: This is typically a combination of air pump and excess water outlet, to maintain right amount of water + air reaching the roots.
- Plants: Plants grow with their leaves/ stem outside of the container, and their roots growing down inside. Roots are partially immersed into the solution with air bubbling through it, supplying oxygen. Soils is not used at all. Instead the plants are supported by net cups tucked into the lid of the container. Net cup is filled with gravel of perlite or leca, with a water-holding porous element such as rockwool.
There are plenty of variants of this model. All variations require that no outside light reaches inside the container, as it is the best way to prevent growth of algae. Many variations use additional artificial lighting systems that need to be controlled manually, to simulate natural daylight cycle. Typically the plants are grown in cycles of 2 to 3 weeks.
My goal is to construct a basic hydroponic system first, and then make an interactive version of it.