Digital Commons Network^™

Efficacy Of Two Hortiled Fixtures, Jakob Johnson, Paul Kusuma, Bruce Bugbee

Controlled Environments

We tested the efficacy of the Full Spectrum and Red-Blue HORTILED TOP LED fixtures manufactured by PL Light. Both fixtures had an 80° light distribution.

The efficacy of the fixtures was measured using flat plane integration as described by Nelson and Bugbee (2014)¹ (see adjacent photo). The fixtures were suspended at 0.65 m above the floor in a 3 × 3 m room with flat black walls. The photosynthetic photon flux density (PPFD, μmol · m^-2 · s^-1) was measured with a recently calibrated quantum sensor (LI-COR model 190R). Measurements were made 2.5 cm apart near …

Sensitivity Of Seven Diverse Species To Blue And Green Light: Interactions With Photon Flux, Michael Chase Snowden, Kevin R. Cope, Bruce Bugbee

Controlled Environments

The effects of spectral quality on growth, carbon-partitioning and whole-plant net assimilation remain poorly understood. Much of the research data is at light levels less than 10% of summer sunlight so interactions between light quality and quantity are poorly characterized.Several studies have reported that growth is increased under fluorescent lamps compared to mixtures of wavelengths from LEDs. Conclusions regarding the effect of green light fraction range from detrimental to beneficial. Here we report the effects of eight blue and green light fractions at two photosynthetic photon fluxes (PPF; 200 and 500 µmol m^-2 s^-1; daily light integral, …

Usu Researchers Find That Lighting Efficiency For Plant Growth Has Doubled In Six Years, Usu Crop Physiology Lab

Controlled Environments

Nelson and Bugbee compared the efficiency of 22 lighting fixtures and found that the best light emitting diode fixtures—commonly known as LEDs—and the best high pressure sodium fixtures—often used in street lamps—are equally efficient. These two types of fixtures, however, provide optimum light for plants in significantly different ways.

Supplemental Greenhouse Lighting: Return On Investment For Led And Hps Fixtures, Jacob A. Nelson, Bruce Bugbee

Controlled Environments

LED fixtures are being marketed as a replacement for high pressure sodium fixtures in greenhouse lighting. Here we compare the cost per photon for LED and HPS fixtures based on their ability to convert electrical energy into photons delivered to a horizontal surface below the fixture. Some LED fixtures now exceed the efficiency of the best HPS fixtures by 23%, but the initial capital cost per photon delivered is 5 to 10 times greater. HPS fixtures with electronic ballasts and optimized luminaires (reflectors) are 27% more efficient than widely-used HPS fixtures with magnetic ballasts. Our analysis, however, demonstrates that light …

Effects Of Blue Light At High Photosynthetic Photon Flux, Saundralyn G. Rhoades, Kevin R. Cope, Chase Snowden, Bruce Bugbee

Controlled Environments

No abstract provided.

Retrofitting Fluorescent Lamp Growth Chambers With Ceramic Metal Halide Lamps, Usu Crop Physiology Lab, Bruce Bugbee, Jacob Nelson

Controlled Environments

A how-to guide on how to retrofit fluorescent lamp growth chambers with ceramic metal halide lamps.

Retrofitting Older Growth Chambers To Improve Ppf, Electrical Efficiency And Uniformity, Jacob A. Nelson, Bruce Bugbee

Controlled Environments

A how-to guide on how to retrofit older growth chambers to improve PPF, electrical efficiency and uniformity.

Three Challenges Of Controlled Environment Research, Bruce Bugbee

Controlled Environments

A presentation given to show ways to grow plants in controlled research environments to more resemble plants found in the wild.

Partial Capacitor Failure In Hid Lamp Ballasts: An Insidious Problem, Jacob Nelson, Alec Hay, Bruce Bugbee

Controlled Environments

Supplemental lighting is responsible for a large portion of the power consumption in growth chambers and greenhouses. Lights not functioning at peak efficiency reduce growth and increase electric consumption. HID lights that appear to be working normally can have a significant reduction in light output without being visually apparent.

Cooling With Water: An Economical Alternative For Plant Growth Chambers, Alec Hay, Bruce Bugbee

Controlled Environments

The most expensive component of a growth chamber is the cooling system. When the compressor fails, replacement can cost $2,000 to $3,000. The age of a growth chamber or the availability of funding may make replacement of the compressor impractical. Such a growth chamber is the ideal candidate for conversion to water-cooling. While the chamber will not be capable of cooling to near freezing temperatures, a fully functional chamber can be up and running for a few hundred dollars, and it will serve fully 90% of experiments commonly done in growth chambers.

Three Challenges Of Controlled Environment Research, Usu - Crop Physiology Lab

Controlled Environments

Three "myths" are tested to determine optimal growing conditions for plants in a controlled research environment.