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Introduction to Hydroponics

A simple, to the point definition of hydroponics is: a way to grow plants using water and nutrients. Hydroponics is superior to growing in soil because you can give plants maximum levels of the exact nutrients they need. Precise control of nutrient uptake makes it possible to reap higher yields faster.

How does a plant work?

Leaves are where photosynthesis—the process in which sunlight combines with CO2 and water and is then taken up by the roots to manufacture food (carbohydrates) for the plant—takes place and oxygen is released as a by-product. Plants regulate small openings, stomata, on leaf undersides to allow CO2 to enter and oxygen (O2) to exit. When open, stomata allow water vapor to escape in the process of transpiration.

Roots anchor a plant in the ground and absorb water, nutrients, and air. Hydroponics allows absorption of water, nutrients, and air at an accelerated rate. Tiny root hairs increase the surface area of absorption. These root hairs are very delicate and must be moist at all times. Large roots are similar to stems. They transport water and dissolved minerals (fertilizer) in the phloem.

Stems have a vascular system to transport water and nutrients throughout the plant. The xylem carries water and dissolved minerals from roots to leaves. The phloem transports food manufactured by leaves to the stems and roots. The vascular cambium is the growth zone that produces xylem on one side and phloem on the other. The stem also supports the plant and bears leaves, buds, flowers, and fruit.


Air: Temperature, Humidity, CO2 and O2 Content
Light: Spectrum (color), Intensity, Photoperiod (hours of light per day)
Water: Temperature, pH, EC, Oxygen Content
Nutrients: Composition, Purity
Growing Medium: Air Content, Moisture Content

Where do I start?

Once you’ve made the decision to grow hydroponically, you must decide where you want to garden: indoors, in a greenhouse, or outdoors. Next you must decide how to control the garden atmosphere. The chart below will help you with the appropriate cost of different items needed for each type of garden.

*Bold indicates optional supplies

*Click on Check List to find items at Hydroponics Unlimited


Check List





Hydroponic System $30-$500 Yes Yes Yes
pH Meter $30-$100 Yes Yes Yes
EC Meter $30-$100 Yes Yes Yes
Ventilation Fan $50-$200 Yes Yes
Circulation Fan $20-$100 Yes Yes
Thermometer $5-$30 Yes Yes Yes
Hygrometer $5-$50 Yes Yes Yes
Thermostat $30-$150 Yes Yes
Humidistat $50-$150 Yes Yes
Timer $30-$50 YEs Yes
Controller $100-$500 Yes Yes
CO2 $200-$400 Yes Yes
Air Filter $5-$200 Yes Yes