Hydroponics is the cultivation of plants with their roots in a nutrient solution rather than soil. All mineral nutrients come from dissolved salts. Roots sit either directly in water (deep water culture, NFT, aeroponics) or in an inert support medium such as rockwool, clay pebbles or coco that holds little or no nutrition of its own.
In practice
Because the grower supplies every element, hydro gives fast growth and precise control, and mistakes show quickly. The key numbers to manage are EC (often about 1.0-2.4 mS/cm depending on stage), pH (about 5.5-6.5), solution temperature (about 18-22 °C, 64-72 °F) and dissolved oxygen. Systems are either recirculating (solution returns to a reservoir) or drain-to-waste (each feed is used once).
Many growers count coco and rockwool fertigation as hydroponics; purists reserve the word for systems with roots in water.
Don't confuse with
- Soilless: any medium without mineral soil, including peat mixes; not always fed like hydro.
- Aquaponics: hydroponics fed by fish waste via a bacterial biofilter.
Myth check
House position: a well-grown hydro run gives a well-grown living-soil run a run for its money, even on taste. Plants mostly don't care where ions come from. Whether soil biology adds something extra is an open question for a blind Bay Trial.
DWC (deep water culture) suspends a plant's roots in an aerated nutrient solution, typically in a bucket with a net pot lid and an air stone.Clay pebbles (LECA) are fired, expanded clay balls used as an inert hydroponic medium that drains freely, holds a little water and anchors roots.Coco coir is a growing medium made from processed coconut husk, prized for holding water and air at once; it binds calcium and magnesium unless buffered.EC (electrical conductivity) measures how well a solution conducts electricity, a proxy for total dissolved salts; growers read it in mS/cm to gauge nutrient strength.A recirculating (closed) system returns drained nutrient solution to the reservoir to be reused, saving water and nutrients but needing more monitoring and sanitation.Drain-to-waste fertigation feeds each plant fresh nutrient solution and lets the runoff leave the system rather than returning it to the reservoir.Fertigation is delivering fertiliser dissolved in irrigation water, so plants are fed every time they are watered rather than through solid amendments.Bay Trials are GenetixBay's member-run controlled grow experiments that test growing claims side by side and publish the results openly.A soilless medium contains no mineral soil, such as peat, coco, rockwool or perlite blends, and relies mostly on the grower to supply nutrients.NFT (nutrient film technique) runs a thin, continuous film of nutrient solution along sloped channels, with roots resting in the stream and exposed to air above.A reservoir is the tank that holds a system's water or nutrient solution, the place where pH, EC, temperature and oxygen are measured and adjusted.
