450 nm BLUE
This light enacts regulation by cryptochromes and phototropins, mediating various plant
responses, such as phototropic curvature, inhibition of elongation growth, chloroplast
movement, stomatal opening and seedling growth regulation. Can be directly absorbed
by chlorophyll in photosynthesis. Recommended as supplemental light for seedlings and
young plants during the vegetative stage of their growth
cycle, especially when “stretching” must be reduced or eliminated.
525 nm Green
The 525nm wavelength LED can be used as a tool for eliciting specific plant
responses such as stomatal control, phototropism, photomorphogenic growth and
environmental signaling. When combined with blue, red and far-red wavelengths,
525nm completes a comprehensive spectral treatment for understanding plant
624 nm RED
This wavelength region has the highest photosynthetic relative quantum yield for a range
of plants. At the same time, its action on red-absorbing phytochrome is considerably
weaker compared to that of 660 nm red light and can be used to balance the
phytochrome equilibrium towards lower values (closer to those of daylight) than those
achievable with 660 nm red light, especially when used together with 730 nm red light
660 nm DEEP RED
This wavelength has a very strong photosynthetic action and also exhibits the highest
action on red-absorbing phytochrome regulated germination, flowering and other
processes. Most effective for light cycle extension or night interruption to induce
flowering of long-day plants or prevent flowering of short-day plants. Most energyefficient source for photosynthesis among all available supplemental LEDs.
730 nm FAR RED
Although this wavelength is outside the photosynthetically active range, it has the
strongest action on the far-red absorbing form of phytochrome, converting it back to
the red-absorbing form. It becomes necessary for plants requiring relatively low values
of the phytochrome photoequilibrium to flower. Can be used at the end of each light
cycle to promote flowering in short-day plants.
Best for human visualization
The IES™ HV spectrum, inspired by NASA, is a good choice for growing situations where it’s important for people to see plants as we’re accustomed to seeing them — that is, green. The purplish light cast by many grow lights wouldn’t work in situations where we want to see the plants — for example, on a decorative grow wall. HV provides good light for plant growth, along with light that allows humans to see the plants.