Glossary for Vertical Farming

About the Association for Vertical Farming

The Association for Vertical Farming has created the first glossary for vertical farming and urban agriculture with the combined effort and feedback of its members and board. Click on any word in the glossary below to find out more about the terminology used within vertical farming and urban agriculture. If you have recommendations of things we should add to the list or feedback on the content please send us an email through the contact form titled “Glossary”.


generally refers to a situation that requires, or involves free oxygen

types of bacteria that require oxygen to survive

LPAsystems use a standard magdrive pump coupled to PVC or tubing, and a few miniature sprinkler heads. The water spray from an LPA sprinkler head has large droplets that surround the plant roots. LPAs generally run uninterupted and therefore resemble NFT, continually wetting the roots with more volume of water than HPA. They are not as efficient as HPA systems but much cheaper to build

HPAsystems must operate at a high pressure, normally above 80 PSI. The high pressure is used to atomize the water through a small orifice to create water droplets of 50 microns or less in diameter. HPA must also run on an accurate time cycle; usually running 1 to 5 seconds on, followed by 3 to 5 minutes off. Specific components are required in controlling the timing interval and creating the proper size mist.

is the process of introducing and integrating oxygen into a liquid or other substance.

Any water that is carrying away byproduct from a farm. May contain fertilizers, contaminants, etc.

is a broad term used to describe cultivation of plants, livestock, fungi, and other life forms to serve human interests in the form of resources.

the combination of agriculture and architecture. Used in reference to buildings that produce food.

a device that uses compressed air to pump water vertically.

is a form of aquaculture involving the farming of species of algae. The majority of algae that are intentionally cultivated fall into the category of microalgae (also referred to as phytoplankton, microphytes, or planktonic algae). Macroalgae, commonly known as seaweed, also have many commercial and industrial uses, but due to their size and the specific requirements of the environment in which they need to grow, they do not lend themselves as readily to cultivation (this may change, however, with the advent of UAS seaweed cultivators using upflowing air bubbles in small containers).

a very large an diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. Algae is Latin for “seaweed”.

crops that live up to one year and do not return once harvested

(or pisciponics), is a food production system that combines conventional aquaculture, (raising aquatic animals such as snails, fish, crayfish or prawns in tanks), with hydroponics (cultivating plants in water) in a symbiotic environment. The goal of aquaponics is to be a more efficient and sustainable form of food production

any lighting that is not sunlight


a starter plug made of organic material, bound together by latex. See also starter plugs.

blue grow lights are used to foster vegetative growth of plants, and have a wavelength between 400-500 nm.

when a plant sends up a flower stem

is a container similar to a terrarium in which plants are grown. They usually consist of a plastic or glass bottle with a narrow neck and a small opening.[1] Plants are grown inside the bottle with little or no exposure to the outside environment, and can be contained indefinitely inside the bottle if properly illuminated.[2] The oldest known bottle garden in existence was planted in 1960 and sealed in 1972.

the practice of locating high performance hydroponic greenhouse farming systems on and in mixed use buildings to exploit synergies between the built environment and agriculture.


a series of chemical reactions that convert carbon dioxide to glucose, a part of photosynthesis.

the movement of a liquid along the surface of a solid caused by the attraction of molecules of the liquid to the molecules of the solid.

a colorless, tasteless and odorless gas that is a necessary input to the photosynthetic process. It occurs naturally in the atmosphere at approximately 400 parts per million.

is a pigment that participates directly in light acquisition, and the light reactions of photosynthesis. It’s thus considered the primary photosynthetic pigment. It absorbs both red and blue light, and reflects green, hence its color.

serves essentially the same function as Chlorophyll A, absorbing light for the process of photosynthesis. Its contribution is slightly more indirect however, as it transfers the absorbed light to A for it to do its work in the light reactions of photosynthesis. B absorbs more blue light than A, so it aids A by expanding on its range of light.

a condition in which the plants leaves fail to produce enough chlorophyll. This manifests itself by leaves that are pale, yellow or yellow-white.

(see: urban agriculture)

commonly known as Hydrocorn or Hydroleca, clay pebbles are an organic growing media for hydroponics. They are made from clay that has been heated in a rotating kiln to 1100 – 1200 degrees Celsius. The result is a rough finished, highly porous medium that is brilliant at retaining moisture, trapping air, and oxygenating any nutrient solution which flows over it, which in turn provides plenty of aeration to the root zone. Clay pebbles support plants and the root system and as a non-degradable, PH neutral medium, they can be re-used providing they are properly sterilized before being used again. Overall, clay pebbles are an easy growing medium to work with.

made from the husk of coconuts. Coco is a very popular choice with many growers as it brings the forgiving buffering properties of soil together with the high performance and aeration properties that are typical of good hydroponic systems. Coco is an inert medium, meaning growers have full control over maintaining optimum nutrient levels. It is also better than most other mediums at promoting beneficial bacteria growth and protecting the root zone from heat stress. Plant performance in coco has been well documented. A lengthy study by the International Symposium on Growing Media and Hydroponics found coco to outperform rockwool, increasing yields by almost 20%. Overall, coco is a highly versatile substrate that can be used in most hydroponic systems and can be mixed with other mediums like clay pebble

a structure built to extend the growing season by protecting plants from harsher environmental elements (frost, wind, snow, etc.).

the planting of different crops in proximity to each other for pest control, pollination and to otherwise increase crop productivity.

the graduated difference in concentration of a solute per unit distance through a solution.

is any agricultural technology that enables the grower to manipulate a crop’s environment to the desired conditions. CEA technologies include greenhouse, hydroponics, aquaculture, and aquaponics. Controlled variables include temperature, humidity, pH, and nutrient analysis.

sometimes known as community-shared agriculture, is a locally-based economic model of agriculture and food distribution. A CSA also refers to a particular network or association of individuals who have pledged to support one or more local farms, with growers and consumers sharing the risks and benefits of food production. CSA members or subscribers pay at the onset of the growing season for a share of the anticipated harvest; once harvesting begins, they receive weekly shares of vegetables and fruit, in a vegetable box scheme. Additionally there are initiatives, which are supported by internet users either through a buy-in scheme or leasing plan. Members can explore the farm online, order produce that they want, and see the farms progress.

a plan for growing crops that will produce regular and consistent harvests.

can serve as a relatively efficient grow light. It can be an inexpensive option for small-scale growers.

(see: hardiness zones)

is the act of preparing, and subsequently maintaining land or, in the case of hydroponics, a soilless system to produce crops.


the number of photosynthetically active light particles, or photons, received during one day in one square meter of particular location.

is a hydroponic method of plant production by means of suspending the plant roots in a solution of nutrient-rich, oxygenated water. Bubbleponics is a related method of plant production that involves a top-fed deep water culture system. A more accurate definition for the acronym DWC is Direct Water Culture. Direct Water Culture can be performed in deep or shallow water.

device that removes moisture from the air.

a substance with the ability to attract and hold water molecules from the surrounding environment.

any hydroponic system where runoff is part of normal operation, sometimes referred to as a non-recovery system.

also known as trickle irrigation, micro irrigation or localized irrigation, is an irrigation method that saves water and fertilizer by allowing water to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone, through a network of valves, pipes, tubing, and emitters. It is done through narrow tubes that deliver water directly to the base of the plant.

tubing, usually of a small diameter, used to deliver nutrient solution from a reservoir to a plant site.

a type of drip system, that utilizes special buckets designed to maintain a small reservoir (about an inch deep) at the bottom of the bucket. It is also designed so that the water in the reservoir is not stagnant.


is a form of hydroponics. Pots are either filled with soil or an inert medium (does not function like soil or contribute nutrition to the plants), which anchors the roots and functions as a temporary reserve of water and solvent mineral nutrients. The hydroponic solution alternately floods the system and is allowed to ebb away.

electrical conductivity measures the easiness in which an electrical charge can flow through a certain length of a certain material. It is usually measured in S/cm which just means that the material has a certain conductance in S (Siemens) per centimeter.

is power derived from either physical or chemical resources, which is mostly used to create light or heat, or to power machinery. Energy can be produced from sustainable sources such as solar or wind power, or from non-renewable resources such as coal or natural gas.


a subset of BIA, this type of farm is integrated into the facade of a structure.

a ratio that measures an animal’s efficiency regarding the conversion of food to an increase in output, usually body mass.

a metabolic process converting sugar to acids, gases and/or alcohol using yeast or bacteria

is the application of fertilizers, soil amendments, or other water-soluble products through an irrigation system. Chemigation, is the application of chemicals through an irrigation system. Chemigation is considered to be a more restrictive and controlled process due to the potential nature of the products being delivered – pesticides, herbicides, fungicides – to cause harm to humans, animals, and the environment. Therefore chemigation is generally more regulated than fertigation.

is material that is added to either soil or, in the case of hydroponics, the nutrient solution that provides one or multiple necessary nutrients. It can be derived from synthetic or naturally-occurring sources, and can be either organic or inorganic.

the stage of growth after the vegetative phase necessary for sexual reproduction and fruit production.

(see aquaculture)

is a form of aeroponics which uses water in a vaporised form to transfer nutrients and oxygen to enclosed suspended plant roots. Fogponics includes a foliar feeding mechanism and utilizes a 5-30 µm mist within the rooting chamber. Plants best absorb particles from the 1-25 µm range, the smaller particulate size means faster absorption. The added benefit of using fogponic’s over traditional hydroponics systems is that the plants require less energy in root growth and mass, and are able to still sustain a large plant.

is a district with little or no access to large grocery stores that offer fresh and affordable foods needed to maintain a healthy diet. Instead of such stores, these districts often contain many fast food restaurants and convenience stores.

refers to the conditions and practices that preserve the quality of food to prevent contamination and foodborne illnesses.

refers to the availability of food and one’s access to it.


process of getting a seed to sprout.

the percentage of seeds that germinate in a given planting.

(also called a glasshouse) is a building in which plants are grown. These structures range in size from small sheds to industrial-sized buildings.

or plant light is an artificial light source, generally an electric light, designed to stimulate plant growth by emitting an electromagnetic spectrum appropriate for photosynthesis. Grow lights are used in applications where there is either no naturally occurring light for photosynthesis, or where supplemental light is required.

(see substrate)

a tray used to hold hydroponically-grown plants. Different grow trays are needed for different hydroponic setups. For example, a grow tray for an ebb and flow system must be relatively deep to allow for flooding.


geographic areas defined by climatic conditions, specifically minimum temperatures.

as an action, to collect plants (or their fruits) for consumption or use. As an event, time of growing season when crops are harvested.

two types of high intensity discharge (HID) grow lights are used in indoor and soilless growing. The first is a metal halide lamp, which provides blue spectrum light needed for vegetative growth. Second, high pressure sodium (HPS) lights provide the red spectrum light required for flowering. HID grow lights are generally more suitable for larger-scale growers, as they’re more expensive, and require more attention than CFLs, as they can get quite hot. HIDs are significantly more efficient than CFLs overall, however.

are defined as the instance where vegetation and an architectural/architectonic system exist in a mutually defined and intentionally designed relationship that supports plant growth and an architectonic concept. The most common form of these systems in contemporary vernacular is green wall, vertical garden, green roof, roof garden, building-integrated agriculture (BIA), yet the history of these systems may be traced back through greenhouse technology,[1] hydroponicums, horticultural growth chambers, and beyond. These horticultural building systems evolved form a reciprocal relationship between plant cultural requirements and architectural technology.

is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits,vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and non-food crops such as grass and ornamental trees and plants. It also includes plant conservation, landscape restoration, landscape and garden design, construction, and maintenance, and arboriculture.

a heated greenhouse. See also: greenhouse.

device that adds moisture to the air.

an organic compound that is made up entirely of hydrogen and carbon.

is a subset of hydroculture and is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, expanded clay pebbles or coconut husk.

is a farm, garden, or building devoted to soilless cultivation or hydroponics.

commercial brand name for LECA (lightweight expanded clay aggregate) that is used as a growing medium in hydroponic systems.

a higher concentration of solutes than surrounding solutions.

a lower concentration of solutes than surrounding solutions.


is often done to foster a controlled environment for whatever plants are being grown. It’s a great method for growing all year around (even in Winter), and hydroponics is often employed.

has only recently become more widely used among growers. Invented by Nikola Tesla, they operate on the principle of electromagnetic induction, and thus are very efficient. As of now, they’re a rather expensive investment, but have the potential to pay for themselves over time due to their efficiency.

substance that is unable to dissolve

an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Also referred to as integrated pest control (IPC).

agriculture that is designed primarily to integrate with the interior of a structure.

strands or bundles of vascular tissues forming the principal framework of a leaf.

solutions that have te same concentration of solutes.




s a relatively inexpensive and efficient lighting option for any grower. The spectrum LEDs provide can be easily customized, as a wide variety of color options are now offered.


provide blue spectrum light needed for vegetative growth. Therefore, they are used during this period of a plant’s life cycle, before the grower switches to high pressure sodium (HPS) lights for the flowering stage.

is a term created recently by Australian urban farmer, Gary Donaldson to describe his integrated backyard food production concept. While Microponics was also the name given to an obscure grafting method used in hydroponics, Donaldson’s use of the term was derived from the integration of micro-livestock (and micro-farming) and the production of fish and plants – aquaponics.

a unit of measurement used to express quantitiy of photos. One mol = 6,02×1023. This is referred to as Avagado’s number.


the death of cells or tissues due to injury or disease, especialy in a localized area of the plant.

plastic flower pot with drainage holes, optimized for hydroponics.

the physical manifestation of feeding the plants a overly concentrated nutrient solution.

is a hydroponic technique wherein a very shallow stream of water containing all the dissolved nutrients required for plant growth is re-circulated past the bare roots of plants in a watertight gully, also known as channels. In an ideal system, the depth of the recirculating stream should be very shallow, little more than a film of water, hence the name ‘nutrient film’. This ensures that the thick root mat, which develops in the bottom of the channel, has an upper surface, which, although moist, is in the air.

a condition when a plant can not access specific or all nutrients in the growing medium, this is due to a chemical reaction within the meidum/solution which prevents nutrients from being absorbed by the roots.

are components in food that are utilized by organisms to survive and grow. They are typically divided into macronutrients, which provide the majority of energy needed, and micronutrients, which aid in metabolism.

a water based solution containing mainly inorganic ions from soluble salts of all the macro and micro nutrients that a plant needs.


brand name for a very porous foam-like material used as starter plugs. See also: starter plugs.

specialized subunits within a cell that each have a specific funtion. The name organelle comes from the idea that these subunits are to cells what an organ is to the human body.

refers to any material that is, or is derived from, living matter. The term is also used in food production, referring to food that is produced without synthetic fertilizers or pesticides (and other rules and regulations that differ per location).

aspects of foods that relate to the senses: sight, smell, tuch and tase.

is a system of urban organic gardens in Cuba. They often consist of low-level concrete walls filled with organic matter and soil, with lines of drip irrigation laid on the surface of the growing media. Organopónicos are a labour-intensive form of local agriculture.

the passage of a solvent through a sempipermeable membrane, from a less concentrated to a more concentrated solution, until both solutions are on the same concentration.


semi-hydroponics or passive subirrigation is a method of growing plants without soil, peat moss, or bark. Instead an inert porous medium transports water and fertilizer to the roots by capillary action. Water and fertilizer are held in a reservoir and conducted to the roots as necessary, reducing labor and providing a constant supply of water to the roots. In the simplest method, the pot sits in a shallow solution of fertilizer and water or on a capillary mat saturated with nutrient solution. Since routine maintenance is much simplified, passive hydroponics can reduce the labor required to maintain a large collection of plants.

gravel that consists of small, rounded stones, used in concrete walkways, driveways and as a substrate in home aquariums.

an organic material, often found in marshy or damp regions, composed of partially decayed vegetable matter, useful as fertilizer and fuel.

crops that return season after season.

is composed mainly of minerals and is an expanded volcanic glass. The expansion process gives perlite a very porous structure and fantastic aeration properties. It is also pH neutral and a highly absorbent substance that’s great at retaining water and nutrients, without shrinking or getting soggy. As an inert substrate, hydroponic growers can benefit from optimum nutrient control when using perlite. However, growers rarely use perlite as a sole growing medium.

a method of horticulture that utilizes renewable resources in order to create a self-sustaining ecosystem.

stands for “potential of hydrogen”, and represents the acidity or alkalinity of a solution. Soil pH typically falls between 4 and 8, with optimal nutrient availability for most plants existing between 6.5 and 7.0.

a tiny particle of electromagnetic radiation.

in order to absorb light for photosynthesis, plants need the help of cells known as ‘photopigments’. The two most significant photopigments in the process are Chlorophyll A & B. Carotenoids also serve as accessory pigments, expanding the spectrum of absorbable light.

is the wavelength range of solar radiation that plants are able to utilize for photosynthesis. The range is 400-700 nanometers.

is the process employed by plants to convert light energy from the sun and other sources, such as grow lights, to chemical energy. The required inputs are light, CO2 and water, with the outputs being sugar and oxygen.

the number of micromoles of photosynthetically active radiation (PAR) irradiating a square meter of space every second.

the core area within plant tissue, composed of proteins, pigments, and other co-factors, that captures the photons of light energy and turns it into a usuable form (photosynthesis).

any light particle (photon) that falls within that wavelength range of 400-700nm.

containing or growing hairs as related to plants, e.g. the hairs on tomato plants.

forcing a plant into a state of extreme dryness by use of a desiccant. See also: desiccant.

southeast Asian term for “Vertical Farm”. see also: vertical farm(ing).

essentially regulate the growth of a plant. They regulate cell processes, and also control the formation of fruits, stems, flowers, and when leaves are shed among other functions.

(see plant recipe)

the optimal combination of input information of environmental, light and water settings for the growth of a plant. Resulting in the fastest growth rates, highest yields and uniformity.

food production in the interstitial spaces between buildings in urban areas.

a fungus that rots a plants roots, also known called root rot.



sny hydroponic system that operates as a closed loop and does not have any runoff as part of normal operation. Also known as a recovery system.

red grow lights are used to foster flowering in plants, and have a wavelength between 600-700 nm.

in general terms, a reservoir is an area, usually man-made, where a liquid is stored. In hydroponics, it refers to the area of the setup where nutrient solution is stored.

is also commonly known as mineral wool or stone wool, is widely used in commercial hydroponic applications and for plant propagation. Most of the tomatoes you see in your local store are grown hydroponically using rockwool. However, rockwool can be used in various hydroponic set-ups to grow a whole host of delicious crops. Rockwool itself is an inert medium which is made by melting basaltic rock. This melted mixture is then spun into thin fibers which are cooled by air.

a greenhouse on an urban rooftop that utilizes hydroponics.

area below the main stalk of the plant where the roots are located.

is a circular hydroponics setup that rotates constantly during the plants’ life cycles. Usually, a high intensity light is situated in the middle of the setup.


a young plant developing out of a plant embryo from a seed.

a membrane that only allows certain molecules or ions to pass through it by diffusion. Also known as a selectively permeable membrane.

a variation of water culture hydroponics. Benefits include cost-effectiveness of construction and more densely stacked vertical farming. Suitable for smaller micro-greens and herbs.

broadly refers to, and is based on the concept that plants do not require soil to grow. A variety of methods are employed, all of them allowing for significant environmental benefits (see hydroponics).

substance that can be dissolved.

substance which will dissolve other substances.

in the context of plant growth refers to the range of wavelengths that are used for photosynthesis. Red spectrum (wavelengths between 600-700 nm) and blue spectrum (wavelengths between 400-500 nm) are primarily utilized.

very small sample of a solid growing medium, optimized for seed germination.

minute openings, like pores, found in the epidermal layer of leaves that regulate gas exchange.

sponge-like material made from molten rock that is used as a medium for starting seeds and growing plants hydroponically. Commonly known by the brand name Rockwool.

may also be referred to as “growing mediums”. In biology, a substrate is the surface on which a plant or animal lives. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock (its substrate) can be itself a substrate for another animal that lives on top of the algae. Substrates are necessary in hydroponic systems in the absence of soil, as plants still require support. Non-organic materials such as coconut coir, perlite, rockwool, or clay pebbles are used. The materials ensure proper aeration and access to nutrients.

is a newer technology and thus quite expensive. They’re a form of induction grow lights that use sulphur halides.


the classification of organisms in an ordered system, that indicates natural relationships.

can be used in automated hydroponic systems to control growing conditions, allowing users to set nutrient application intervals, etc.

a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or micro-granular suspended form.

the passage of water through a plant from the roots through the vascular system to the atmosphere.


a subset of BIA. This type of farm is located below-grade, usually in urban centres. These farms utilize no natural light.

is the practice of cultivating, processing, and distributing food in or around a village, town, or city.[1] Urban agriculture can also involve animal husbandry, aquaculture, agroforestry, and horticulture. These activities also occur in peri-urban areas as well.

is the practice of integrating organic, hydroponic, aeroponic or aquaponic farming technologies into buildings of all types. An example can be as small as building a lean-to-greenhouse on a single-family home and using it as a kitchen garden.

(see urban agriculture)


the period of plant growth between germination and flowering.

a form of asexual reproduction in plants.

any of a group of flaky minerals, hydrous silicates of aluminium, magnesium and iron that expand markedly on being heated. Was formerly popular for use as a plant growing medium and insulation, until discovering impure vermiculite may be contaminated with asbestos.

Vertical farming is the practice of growing food and/or medecine in vertically stacked layers, vertically inclined surfaces and/or integrated in other structures.The modern idea of vertical farming uses Controlled Environment Agriculture (CEA) technology, where all environmental factors can be controlled. These facilities utilize artificial control of light, environmental control (humidity, temperature, gases,..) and fertigation. Some vertical farms make use of techniques similar to greenhouses, where natural sunlight can be augmented with artificial lighting.”

is a method of composting that utilizes earthworms (often red wrigglers) to break down organic matter at an accelerated rate compared to most methods of composting. The result is a rich, aerated compost that contains worm castings that feature higher levels of microbial activity than most soil.


(see vertical farm)

(see Photon)

a type of passive hydroponics systems that uses a wick and capillary action to transport of nutrients from a reservoir to the root zone of a plant. See also: passive hydroponics.

a plant tissue that conducts water and mineral salts from the roots to all other parts, provides mechanical support and forms the wood of trees and shrubs.