Supplying soil and roots with air or oxygen. Geolite is an example of a medium with
excellent aeration. In some hydroponic systems, a nutrient solution is aerated by
the output of an aquarium pump.
A system in which the roots of a plant are consistently or intermittently misted
with fine droplets of nutrient solution.
Refers to medium or nutrient solution with a low pH; an acidic solution has a pH
Refers to medium or nutrient solution with a high pH; any pH over 7 is considered
BLOOM BOOSTER, BLOSSOM BOOSTER
Fertilizer high in phosphorus (P) that increases flower yield.
The function of this micronutrient is not well understood, but it is suspected that
it might aid carbohydrate transport.
Leaf tips that turn dark from excess fertilizer and salt burn.
Calcium is vital in all parts of plants to promote the translocation of carbohydrates,
healthy cell wall structure, strong stems, membrane maintenance and root structure
development. Calcium is a macronutrient.
CARBON DIOXIDE (CO2)
A colorless, odorless, tasteless gas in the air necessary for plant life. Occurs
naturally in the atmosphere at .03%.
This micronutrient is essential for photosynthesis, where it acts as an enzyme activator
during the production of oxygen from water.
The condition of a sick plant with yellowing leaves due to inadequate formation
of chlorophyll. Chlorosis is caused by a nutrient deficiency, usually iron or nitrogen;
nutrient deficiencies are themselves often caused by a pH that is out of the acceptable
A plant produced through asexual reproduction including, but not limited to, cuttings,
layering and tissue culture.
To soak new Rockwool in an acidic solution to lower the pH from 8.0 to 5.5.
This micronutrient is an internal catalyst and acts as an electron carrier; it is
also believed to play a role in nitrogen fixation.
Disease that attacks young seedlings and cuttings, causing stems to rot at the base;
overwatering is the main cause of damping-off.
DISSOLVED SOLIDS or TOTAL DISSOLVED SOLIDS
The amount of dissolved solids, usually fertilizer salts, that are measured in water
in parts per million.
A hydroponic method wherein air pressure from a small air pump is used to percolate
nutrient solution out through a ring of feeder tubing which encircles the plant.
DRIP SYSTEM (DRIP EMITTER SYSTEM)
A very efficient watering system that employs a main hose with small water emitters.
Water is metered out of the emitters, one drop at a time.
EBB-AND-FLOW (or FLOOD and DRAIN)
A hydroponic system in which the medium, usually aggregate pebbles, is periodically
flooded with nutrient solution and then drained again, feeding and aerating the
medium and root system.
Misting plants with fertilizer solution, which is absorbed by the foliage.
A product that destroys or inhibits fungus.
Any of a major group (Fungi) of saprophytic and parasitic spore-producing organisms
usually classified as plants that lack chlorophyll and include molds, rusts, mildews,
smuts, mushrooms, and yeasts. Common fungal diseases that attack plants are "damping-off,"
Botrytis, and powdery mildew.
The process of causing the initiation and development of a plant from seed.
One of several brand names/varieties of clay aggregate medium (also known as LECA
for light expanded clay aggregate). It is a lightweight, porous substrate with excellent
aeration. Because it does not really wick water effectively, Geolite and other LECA
mediums are favorites in ebb-and-flow and drip hydroponic systems.
To gradually acclimatize a plant to a more harsh environment. A seedling must be
hardened-off before planting outdoors.
Chemical substance that controls the growth and development of a plant. Root-inducing
hormones help cuttings root.
The offspring from two plants of different breeds, variety or genetic make-up.
Instantly soluble lime, used to raise or lower pH.
An instrument for measuring relative humidity in the atmosphere.
This micronutrient acts as a catalyst in the photosynthesis/respiration process,
and is essential for the formation of sugars and starches. Iron also activates certain
Leaf malformation due to overwatering, over fertilization, lack of magnesium, insect
or fungus damage or negative tropism.
The primary nutrients N-P-K or the secondary nutrients magnesium and calcium.
This micronutrient activates one or more enzymes in fatty acid synthesis; it also
activates the enzymes responsible for DNA and RNA production. Closely associated
with copper and zinc, manganese also participates directly in the photosynthetic
creation of oxygen from water.
The substrate or soilless material which supports the plant and absorbs and releases
the nutrient solution in hydroponic horticulture.
Also referred to a TRACE ELEMENTS, including S, Fe, Mn, B, Mb, An and Cu.
This micronutrient is essential for nitrogen fixation and nitrate reduction.
The dying of plant tissue, usually the result of serious nutrient deficiency or
Nitrogen is used in various forms to promote rapid vegetative growth, leaf, flower,
fruit and seed development, and chlorophyll development; and to increase the protein
content in all plants.
NFT (NUTRIENT FILM TECHNIQUE)
A hydroponic method in which nutrient is fed into grow tubes or trays in a thin
film where the roots draw it up. This "nutrient film" allows the roots to have constant
contact with the nutrient and the air layer above at the same time.
The elements needed by plants for normal growth and health. The major nutrients
(MACRONUTRIENTS) are nitrogen (N), phosphorus (P), and potassium (K), but there
are numerous MICRONUTRIENTS (also called TRACE ELEMENTS) which also have integral
roles in maintaining plant health. A good quality hydroponic nutrient formula will
contain all of the major nutrients and micronutrients needed by the vast majority
The mixture of water and water-soluble nutrients which is provided to the plants
for nourishment in a hydroponic system.
The elements other than N, P and K which are considered nearly as important as N,
P and K but are not considered micronutrients. Calcium (Ca), magnesium (Mg), and
sulphur (S) are the elements usually referred to by this term.
A scale from 1 to 14 that measures the acid to alkaline balance of a growing medium
(or any other substance). In general, plants grow best in a pH range of 6 to 6.8;
6.3 is considered ideal. If the pH is not within the acceptable range, nutrients
may not be absorbed to maximum capacity.
Phosphorus promotes and stimulates early growth and blooming and root growth. It
hastens maturity and seed growth, and contributes to the general hardiness of plants.
Phosphorus is a macronutrient.
Potassium promotes disease resistance and good development of carbohydrates, starches
and sugars, and it increases fruit production. Potassium is a macronutrient.
1. Sand or volcanic glass which has been expanded by heat; perlite holds water and
nutrients on its many irregular surfaces.
2. Mineral soil amendment.
Day length; the relationship between the length of light and dark in a 24 hour period.
The process by which plants use light energy to collect carbon dioxide from the
atmosphere and convert it to chemical energy in the form of sugar.
Sexual propagation: to produce seed by breeding different male and female flowers.
Asexual propagation: to produce plantlets (also known as CLONES) by taking cuttings.
Natural insecticide made from the blossoms of various chrysanthemums.
The container in a hydroponic system which holds nutrient solution in reserve for
Inert, soilless growing medium consisting of woven, thin strand-like fibers made
from molten volcanic rock and limestone, which is heated to over 2900 degrees F,
extruded, and formed into slabs, cubes and blocks.
Calcium (Ca) and magnesium (Mg) are considered to be the secondary nutrients.
Used in reference to a disease within the plant tissue, not initiated from the external
cells. Also refers to materials and compounds which are taken up or absorbed by
the plant and designed to fight disease (e.g. systemic fungicide).
Mica which has been processed and expanded by heat. Vermiculite has excellent water-retention
qualities and is a good soil amendment and medium for rooting cuttings.
Part of a passive hydroponic system using a wick suspended in the nutrient solution.
The nutrients pass up the wick and are absorbed by the medium and roots.
Like copper and manganese, zinc is linked to chlorophyll synthesis.