Glossary

Carotenes are strongly colored red-orange pigments abundant in plants, fruits, vegetables, and whole grains. Xanthophylls are the typical yellow pigments of leaves. Carotenoids contribute to photosynthesis and protects from excessive light damage. Absorption is strong between 420nm and 485nm.

Chlorophyll a is the primary pigment for photosynthesis in plants. It exhibits a grass-green visual color. It occurs in all photosynthetic organisms except photosynthetic bacteria. Absorption peaks at 430nm to 662nm.

There is usually about half as much cholorphyll b as the -a variety in plants. Exhibits a blue-green visual color. It occurs in all plants, green algae and some prokaryotes. Absorption peaks at 453nm to 642 nm.

A method of growing plants that usually involves small-scale structures inside of individuals’ homes. An increasingly popular activity to provide produce that is non-GMO, chemical and preservative-free.

• Plants need a minimum amount of light per day to meet their basic biological needs, it varies based on species
• For flowering and fruiting high levels of light can show significant increases in both the quality and quantity
• DLI = PPFD (µmol/m2s) x 3,600 (s/hr) x photoperiod (hrs/day)

A method of growing plants that involves a structure, which is usually made of glass or a transparent material, which houses the necessary plants that are being grown. Oftentimes, greenhouses require additional light sources to supplement sunlight.

• Photosynthetic Active Radiation is the bandwidth from 400nm to 700nm, which is the light plants primarily use
• Different plants require different wavelength combinations within the PAR region

The process by which plants convert light energy into sugars to fuel its needs. The rate of photosynthesis is determined by the number of photons between 400nm and 700nm.

• Measured in µmol/s
• Total number of photons emitted per second in the PAR region
• A more relevant measure of a light source’s utility for horticulture, compared to lumens

• Measured in µmol/m2s
• Represents the number of photons that reaches the plant within the PAR region over a given area
• It declines exponentially as the distance between the light source and the plant surface increases

A method of plant growing/food production by which plants are vertically stacked in many layers, usually in an indoor space. Vertical farming oftentimes employs very short distances between layers to maximize the space. Consequently, a light source emitting low heat is necessary.