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How to Choose Lighting For Your Indoor Plant Wall

How to Choose Lighting For Your Indoor Plant Wall

Hint: Remember the "SAP" Rule

The Growing Demand for Indoor Plant Walls

It’s no secret that the number of living wall installations has been skyrocketing in recent years. They support health, promote productivity and are universally attractive to the eye. And while all living walls are seeing an increase in sales, they are finding their greatest growth to be in indoor spaces. From Tesla to Microsoft, businesses all over the US and abroad are insisting on taking their stagnant spaces and breathing life into them. While this can largely be credited to increased awareness through the sharing of health and wellness information over the internet, it can also be attributed to the general growth of infrastructures, businesses and buildings. Companies are willing to spend extra money to ensure that their cows are happy and making only the best milk. A living wall is one of the most popular ways to do this. However, while indoor living walls have the advantage of fewer variables like inclement weather, they do have their limitations – one of the biggest being lighting.

Limitation of Lighting

As everyone knows, plants need two things to grow – water and sunshine. While living wall systems and regular plant maintenance ensure that living walls are properly watered, lighting has remained an issue for many indoor plant installations. Insufficient lighting is the most frequent cause of living wall failures. The design and location of the living wall must be relative to the sunshine it receives, and additionally limits the types of plants used. This not only jeopardizes the quality of the living wall, but many times will prevent its installation altogether. This is an issue that has been recently addressed through grow lights.

Grow Light Science

Grow lights really began to hit the indoor gardening scene with the legalization of marijuana. Engineers and plant scientists found they were able to replicate the sun’s photosynthetic spectrum with manmade lighting. The latest grow lights can perfectly mimic the desired photosynthetic spectrum to replicate the sun perfectly and even manipulate it to best suit how you want to grow your plants. However, people grow plants indoors for many different reasons, and similarly, grow lights are designed to suit those purposes. While most grow lights are designed for agricultural operations and small-scale tabletop plants, there have been very few grow lights designed specifically for living walls. And like other indoor growing systems, living walls have their own unique criteria for effective lighting.

What to Look for in Living Wall Lighting (SAP rule)

There are several factors to consider when evaluating grow lights for your living wall – power, intensity, color temperature, color rendering, and spectrum. As plant people, the best way to remember is with the SAP rule - Spectrum, Appearance, Power.

(S) Spectrum

What gives a grow light the ability to grow plants is their photosynthetic spectrum. The reason why plants react to grow lights rather than regular ambient light is because grow lights target the wavelengths of light that plants respond to. Regular ambient lights neglect to include those wavelengths since they’re outside of basic perception of the human eye. While plants react best to red and blue, the human eye reacts best to green. In recent years LEDs have become the ideal grow light for this exact reason. LEDs can be designed to pinpoint the exact desired chlorophyll peaks along the wavelengths that activate a plant’s growth. A basic rule of thumb is non-flowering plants prefer blue light to encourage leafy growth, while flower plants prefer red light to trigger blooms and flowers. However, since the human eye must be taken into consideration when designing living walls, it is best to include all red, blue and green light in a grow light. These are known as full spectrum grow lights and appear as regular ambient lighting.

(A) Appearance

Unlike many other indoor growing systems, living walls are designed to be admired, which is why appearance of the light displaying them is very important. Kelvin (K) and Color Rendering Index (CRI) value are measurements with which to determine both a light’s appearance and ability to display. Kelvin measures the color temperature of a light and is typically preferred at approximately 3000K or 5000K. 3000K is a warm white color and preferred by interior designers for its inviting ambiance while a 5000K light is a cooler white color and is typically preferred for a crisp and invigorating setting. Color Rendering Index is used to determine how accurately a light displays the true color of the area it lands. It scores from 0 – 100 with 100 being the most natural representation and highest accuracy of true color.

(P) Power

Power becomes important in two ways when considering living wall lighting – strength and appearance. You want a light that’s strong enough to grow your plants, but not too overpowering to become a harsh eyesore in a room. Watts are used to measure the general output of light and Lux and Footcandles are used to measure the intensity and strength with which the photosynthetic light reaches the desired area. It is always best to measure the wall with a light meter to see how much natural light the wall is already receiving before adding the supplemental lighting. This is important because the grow light will add on to any natural light that may already exist in the desired area.

Popular Grow Lights for Living Walls

The installation of a living wall is only half the battle with its long-term success relying on its care. Be sure to keep these products in mind next time considering a living wall.

Kessil - Tuna Sun

According to Kessil, the A160WE/ A360WE Tuna Sun “replicates the look of natural sunlight on the ocean floor”. While originally designed for fish tanks, the Kessil offers a spectrum that can support plant growth.
Spectrum: Photosynthetic
Appearance: 6000K to 9000K CRI Blue/ NA
Power: 40W or 90W

Sunlite - ST30 and ST40

The Sunlite ST30 and ST40 are LED bar lights that maintain the photosynthetic spectrum while giving off white light.
Spectrum: Photosynthetic
Appearance: 3500K or 5500K 75 CRI
Power: 50W

Soltech Solutions - Highland Series

The Highland is an LED track light designed specifically for living walls. Designed to both grow plants while beautifully displaying them, the Highland incorporates both the photosynthetic spectrum and museum quality lighting in to an LED track light.
Spectrum: Photosynthetic
Appearance: 3000K or 5000K 97 CRI
Power: 30W or 100W
Highland Track Light System Black