When you first begin hydroponics it can seem complex. There are so many terms: micro and macronutrients, humidity, temperature, light intensity, PPM, EC, pH, NPK and more. These values matter to industrial growers, but for home growers it is much simpler.
Hydroponics builds on two main requirements: light and a place for roots.
Sunlight or LED grow lights
What is it about the sun that makes plants grow? Most people correctly answer light, but what is the difference between sunlight and the bulb on your ceiling? Why can plants use one and not the other?
It comes down to the specific wavelengths a plant needs. The sun emits a very broad spectrum of light, but most plants mainly use wavelengths between about 400 and 700 nanometres, which we see as violet through to red. These power root growth and the formation of chlorophyll, the green pigment that converts light energy into plant energy through photosynthesis.
In short, plants use only a small slice of the radiation the sun emits. LED grow lights replicate those wavelengths efficiently.
Soil or a hydroponic growth medium?
Humanity depends on the thin layer of topsoil that covers the land. But why can plants grow in soil and not in sand? What does soil give plants, and why do farmers add fertiliser? The answer comes down to three things: support, nutrients and oxygen.
Plant support
Just as a skyscraper's foundations hold it upright, roots anchor a plant in the ground. Roots do much more than that, though.
Nutrients and oxygen
Roots search for oxygen, water and the macro and micronutrients a plant needs. Healthy soil with plenty of microbial life contains all of these, and water releases them into a solution the plant can take up.
What changes with hydroponics?
In hydroponics we swap soil for a growing medium and add our own nutrients. With everything the plant needs within easy reach, it spends less energy searching for resources, which leads to faster growth. With LED lights you can also give plants the light they need in places that would not normally suit growing food.
