Beginners guide to hydroponics
Very simply put, hydroponics is the way of growing plants without soil. No more and no less.
All plants have the same basic needs of light, food (nutrients), carbon dioxide (CO2), water, heat and fresh air. If any of these are lacking the plant will have problems growing. Different plants require these factors in differing ratios but they are all needed whether the plant is in the soil or grown hydroponically.
With soiless gardening we can control and enhance all of a plant's basic needs, we even have the advantage to ensure adequate Oxygen is available to the roots.

