A
Aeration
The process of introducing air into the nutrient solution. This is crucial for providing oxygen to the plant's roots and preventing root rot. It's typically done with an air pump and air stones.
Aeroponics
An advanced hydroponic method where roots hang in the air and are misted with nutrient solution. This provides maximum oxygen to the roots, leading to very fast growth.
B
Bolting
When a plant, typically a leafy green, begins to produce flowers and seeds prematurely, often due to stress like high heat. This can make the plant's leaves bitter and less palatable.
Buffering
The ability of a solution to resist changes in pH. In hydroponics, buffering capacity can help stabilize the pH of the nutrient solution.
C
Chelate
A chemical compound that keeps micronutrients (like Iron) soluble and available to plants over a wider pH range. Most quality nutrient mixes use chelated micronutrients.
Chlorosis
The yellowing of leaf tissue due to a lack of chlorophyll. It's a common symptom of nutrient deficiencies, particularly Nitrogen or Iron.
Clone
A cutting taken from a 'mother plant' that is genetically identical. Cloning is a popular propagation method to create new plants without seeds.
Coco Coir
A natural and sustainable grow medium made from the husk of coconuts. It has excellent water retention and is a popular alternative to peat moss.
D
DWC (Deep Water Culture)
A popular hydroponic method where the plant's roots are suspended in a deep reservoir of highly-oxygenated nutrient solution.
E
Ebb and Flow (Flood and Drain)
A system where a grow bed is periodically flooded with nutrient solution from a reservoir and then drained away. This process provides nutrients and oxygen to the roots.
EC (Electrical Conductivity)
The standard measure of the total amount of dissolved nutrients (salts) in your solution. It tells you the strength of your nutrient mix. Measured in mS/cm.
F
Foliar Feeding
A technique of feeding plants by applying a diluted liquid fertilizer directly to their leaves. It's often used for a quick correction of micronutrient deficiencies.
G
Germination
The initial stage of a plant's growth, where it sprouts from a seed.
Grow Medium
An inert, soilless material that provides physical support for the plant's roots. Examples include Rockwool, Coco Coir, Perlite, and LECA.
H
Hydroponics
The method of growing plants without soil, using mineral nutrient solutions dissolved in water.
K
Kratky Method
The simplest hydroponic method. A plant's roots hang in a static nutrient solution. As the plant drinks, the water level drops, creating an air gap for oxygen. No pumps are needed.
L
LECA (Lightweight Expanded Clay Aggregate)
Small, porous clay pebbles that are a popular, reusable grow medium. They provide excellent aeration and stability for plants but do not retain water well.
N
NFT (Nutrient Film Technique)
A system where a very shallow stream (a 'film') of nutrient solution continuously flows down a channel, passing over the bare roots of plants.
Nutrient Lockout
A common problem where a plant is unable to absorb available nutrients. It is most often caused by the pH of the solution being outside the ideal range for the specific plant.
Nutrient Solution
The water-based, liquid mixture containing all the essential macro- and micro-nutrients that a plant needs to grow.
P
Perlite
A volcanic glass that is heated to expand into a lightweight, white, porous material. It is used to improve aeration and drainage in grow media mixes.
pH
A measurement of how acidic or alkaline a solution is, on a scale of 0-14. The correct pH is critical because it affects the plant's ability to absorb nutrients. Most hydroponic plants prefer a slightly acidic pH (5.5-6.5).
PPM (Parts Per Million)
An alternative measurement for nutrient strength, equivalent to TDS. See TDS.
Propagation
The process of creating new plants, whether from seeds, cuttings (clones), or other plant parts.
R
Reservoir
The main container or tank in a hydroponic system that holds the nutrient solution.
Rockwool
A popular grow medium made from molten rock spun into fine fibers. It has excellent water retention and aeration but has a naturally high pH that needs to be stabilized before use.
Root Rot
A common plant disease where roots turn brown, slimy, and die due to lack of oxygen or fungal infection. It is a major risk in hydroponic systems with poor aeration.
T
TDS (Total Dissolved Solids)
An alternative measurement for nutrient strength, expressed in Parts Per Million (PPM). It is related to EC but can be less accurate as different TDS meters use different conversion factors.
Transpiration
The process by which plants absorb water through the roots and then give off water vapor through pores in their leaves. It's a vital part of plant circulation.
Trellis
A framework of netting or bars used as a physical support for vining or climbing plants like tomatoes and cucumbers.
V
Vermiculite
A mineral that is expanded by heat to form a lightweight, highly absorbent material. It's often used in conjunction with Perlite to create a balanced grow medium.
W
Wick System
A passive hydroponic system that uses a wick (like a rope or felt strip) to draw nutrient solution from a reservoir up into the grow medium.