Lighting Guide for Vertical Gardens

by Chris Bribach

 

Florafelt Vertical Garden by Joanna Wong and Durkin Construction. Cole Valley Residence, San Francisco.

Florafelt Vertical Garden by Joanna Wong and Durkin Construction. Cole Valley Residence, San Francisco.

Plants Need Light

Natural light outdoors is the ideal source for growing plants.

Daylight produces 10,000 foot candles of light. This is perfect for herbs, vegetables, grasses, succulents and many other plants that thrive in full sun or even part shade.

For indoors we select low light tropical plants that are native to the forest floor beneath the tree canopy receiving 250 foot candles and temperatures around 70 degrees. These conditions are typical to our interior spaces. What we consider 'house plants' are suitable to our optimal living conditions as well.

Low light tropical plants typically like bright indirect light however too much light or direct sun will burn their foliage. In places where there is not quite enough light supplemental lighting will be required.

Choosing the right plants for your location is very important.

See Choosing Plants


 

Natural Light

 Florafelt Vertical Garden by Brandon Pruett, Living Green Design. Emeryville Marketplace Living Wall.

 Florafelt Vertical Garden by Brandon Pruett, Living Green Design. Emeryville Marketplace Living Wall.

Free Light Energy From The Sun

Ideal lighting would come from a skylight above or window across from the vertical garden. It costs nothing and is the most ecological solution. Diffused light near a large window becomes ideal conditions for low light tropical plants.

It may be that a beam of light passes over the vertical garden for a couple of hours each day.


 

Know your Light

Get A Light Meter

To determine light levels get a light meter. Light levels are measured in Foot Candles. Low light tropical plants will survive with 150 - 250 foot candles of lighting and will need 8-10 hours each day.

Hydrofarm Digital Light Meter - About $40

 


 

The Color of Light

Kelvin Light Color Compared

Kelvin Color

Choosing the color mostly affects how we will view the plants. Warmer colors recreate summer light that encourages blooming. Bluer light will help plants develop their foliage. Vertical gardens are typically for enjoying their beauty therefore 4000K is a balanced warm daylight that looks best with plants. 


 

Halogen Lighting

Florafelt vertical garden by FireDean Schilling, The Brooklyn Garden Club, Atrium DUMBO.

Florafelt vertical garden by FireDean Schilling, The Brooklyn Garden Club, Atrium DUMBO.

Warm Color

Halogen spot and flood bulbs project light to the plants. Track lighting systems are low cost and easy to install.

Halogen creates a very broad spectrum of light and delivers the most attractive full balanced color making plants look their best. Also they create some warmth that is beneficial for most low light tropical plants.

Florafelt Vertical Garden by Hande Ersoy. Untitled by Flaunt Boutique, Toronto. 

Florafelt Vertical Garden by Hande Ersoy. Untitled by Flaunt Boutique, Toronto. 

Costly to Operate

The downside is that they are not as efficient at producing light as other sources.  Operational cost and ecological impact goes up. Therefore these are best to use for smaller projects or in areas where beauty is most important.

Efficiency in Lumens per Watt

Halogen - 25 Lumens per Watt
Metal Halide - 100 Lumens per Watt
LED Lighting - 100 Lumens per Watt


 

Recirc Interior Lighting Guide

Florafelt Recirc-33 Vertical Garden Lighting Guide

Florafelt Recirc-33 Vertical Garden Lighting Guide


 

Metal Halide Lighting

Florafelt Recirc-24 Vertical Garden Living Wall. Plants On Walls Metal Halide Lighting Test Garden.

Florafelt Recirc-24 Vertical Garden Living Wall. Plants On Walls Metal Halide Lighting Test Garden.

A Full Spectrum

Metal Halide creates full spectrum lighting best for plants

  • UV component
  • Best watt to lumen (foot candle) efficiency

 

Plants Need Ultraviolet Light

Evolved to Love the Sun

Plants have evolved in nature to optimize their photosynthesis at the ends of the spectrum.

In plants, Ultraviolet (UV) blue light are required for green vegetative growth while red wavelengths aid in their flowering and fruiting phases.

For vertical gardens it is desirable to provide plants with a wide spectrum of light so we can also enjoy the visible beauty of plants.


 

Nearly Daylight

A Metal Halide spectrum better mimics sunlight and provides full spectrum for chlorophyll function at 450 nm and 500 nm areas and in the 640 nm and 650 nm wavelengths.

Spectral-Power-Distribution-4200K-GE-ConstantColor-CMH-Ceramic-Metal-Halide-Bulb-T4.5-CMH39TCU942-G8.5-92698.jpg

GE Ceramic Metal Halide Bulb - 4200K

The spectral power distribution diagram of the above bulb shows an even distribution of power in the peak chlorophyll production zones. It also includes a nice balance of the central visible spectrums that also deliver pleasant viewing.

Our test gardens have shown that Halogens do provide adequate light to keep low-light tropical plants alive. Whereas our Metal Halide test gardens show more aggressive growth in bright light loving plants such as ferns.


 

Metal Halide Indoors

Nuvo Lighting Metal Halide Track Head Black 1 T439W/MH/G12 Base, Black, TH382

Houzz about $65 > Buy Online

High quality compact interior fixture. About $160.

Produces about 600 foot candles at 4 feet for each fixture with a spread of about 3 feet diameter and about 150 foot candles at 8 feet with a 2 foot diameter.

Note the bulb must also be purchased, below.

 
Metal-Halide-39-watt-blub-T-4.5.jpg

39 Watt Ceramic Metal Halide Bulb - T4.5 - 4200K

Bulbs Depot about $18 > Buy Online

For fixture above.

 

Easy Metal Halide Lighting
Shopping Resources

A simple track lighting system can be purchased online to create a simple plug-in system. We've created a link page where you can get the parts for an 8' wide track system with timer. This will produce 300 foot candles of energy efficient full spectrum lighting for a 20 square foot tall vertical garden.


Recessed Metal Halide Fixture

Recessed fixtures are available for a more finished look for architectural application.

SYLVANIA 64222 - 70 Watt - PAR30L Spot.jpg

SYLVANIA 64222 - 70 Watt - PAR30L Spot

https://www.1000bulbs.com/product/67422/PLT-64222SP.html


 

Metal Halide Outdoors

Florafelt Pro System Vertical Garden by Tim O'Shey, Chris Bribach, Rock and Rose Landscape. 

Florafelt Pro System Vertical Garden by Tim O'Shey, Chris Bribach, Rock and Rose Landscape. 

Metal Halide Spot Fixture

pro-lighting_2273_112676133.jpg

Metal halide requires a transformer and ballast to ignite the gas in the bulb. These parts are inside it's fairly large base. Note the bulb socket may look like a regular type, but these are for metal halide bulbs only.

To distribute enough light over a wall surface you will need a fixture for each 10 square feet. This fixture will deliver about 300 foot candles to an area about 3' x 3'. If the fixture is far away 10' or more you will need to use a spot to project the light energy to the wall. If closer you can use a flood to distribute the light more evenly.

RAB 70 Watt Metal Halide PAR38 Bullet w/ Hood Bronze 120V
About $150


 

How many watts should I use?

Rule of thumb for most low light tropicals and most ferns:

- 10 Watts per Square foot makes about 400 foot candles.

Example:
- A 20 square foot wall would need 200 watts.
- Use 5 of the 39-watt track light fixtures.

Tips:

- It's always a good idea to round up.

- Use spot bulbs to focus all of the light energy on the wall.


 

The Future of LED Lighting

Are LED Lights good for growing plants?

LED lights hold promise for becoming the best solution for lighting vertical gardens. But currently there are some limitations.

- A spiked spectrum leaves out wavelengths.

- Available bulbs are designed for residential use and remove UV to prevent fading of art and furniture.

- Lights for growers are offered in a pink color to optimize the usable spectrums, but offer a very unattractive light.

- New CREE type bulbs offer promise but are not offered in spot type fixtures that project light energy efficiently.

- More testing of CREE needs to be done to know if it will in fact grow a wide variety of plants with excellent results.

- LEDs are very expensive.


 

Share Your Findings

As we learn more we will update our findings with regards to LED lighting as a practical solution for vertical gardens and living walls. Metal Halide are currently the most viable option.

We are always learning. Let us know your experience.