# Artificial lighting for indoor plants: A brief description with photos.



## Stan Schultz (Aug 17, 2012)

*THE HANGING GARDENS OF SCHULTZ*
My wish was to grow orchids and cacti in Calgary, Alberta Canada. That obviously meant growing them indoors a major part of the year because tropical and subtropical plants seldom do well in subzero temperatures. And, because room on the main floor of our home was in short supply, the basement was the obvious alternative. That, in turn, meant growing them under artificial lighting.

*THE PHYSICAL PLANT*
I hung twelve, standard, 48" (122 cm), twin tube, fluorescent fixtures (a.k.a., shop lights) on short chains from the ceiling joists in my basement. As I recall, they were spaced 14" (~35.5 cm) on center. Between them I mounted standard 10' (3 m) lengths of "1/2 inch electromechanical tubing" (a.k.a., thin-walled conduit) using the same clips used by electricians for fastening conduit. Note that I insisted on using the double-ended variety because the conduits had to hold some significant weight and it was imperative that the clips not bend or come loose. Here are photos of the setup as I was dismantling it in preparation for moving out of the house. Click or right-click the thumbnails for larger images.







In each one of those fluorescent fixtures I merely used one cool white and one warm white fluorescent tube of the 99¢ to $1.99 variety sold in every hardware and building supply store around the world.

These were plugged into standard, high wattage electrical timers of the sort used for controlling small air conditioners and other appliances. They were set to provide approximately 16 hours a day of light and 8 hours a day of darkness.

Parts list (exclusive of minor hardware):

12 Shop light, fluorescent fixtures, 48 " (122 cm), twin tube.
12 Cool white, fluorescent tubes, 48" (122 cm).
12 Warm white, fluorescent tubes, 48" (122 cm).
2 Electric wall timers, each of 1,000 watt capacity or greater. *(This is important! Don't use anything smaller!)*
1 "Third wire ground" heavy duty electrical extension cord with a rating of at least 1,200 watts or 12 Amps. *(This is important! Don't use anything smaller!)* It must also have a 3-outlet head. 
3 Six outlet power bars with built-in circuit breakers, minimum of 700 watts rating each. *(This is important! Don't use anything smaller!)*
4 Twelve foot lengths of 1/2" electrical conduit. (For 4 runs of conduit at 12' per run.) Ten foot lengths will also work, but must be cut appropriately, fit end to end, and securely fastened.

Clips, screws, eye hooks, nylon ties, etc. as needed.

Start with a dedicated, this-project-only, electrical outlet. Make sure that it has its own 15 amp or greater circuit breaker (i.e., it shares power with no other circuit in your home). Replace the  current duplex outlet with a GFI outlet of at least 1,000 watts capacity, or change the circuit breaker in the circuit panel to a GFI breaker. *THIS IS IMPORTANT! DON'T SET UP THIS SYSTEM WITHOUT THESE PRECAUTIONS! If you don't know how to do this, hire an electrician!*

Plug both timers into the "Third wire ground" extension cord.
Plug one power bar into each timer.
Plug 6 shop lights into each power bar.
Strategically station all electrical parts above head level to minimize the chances of getting wet.

I am intentionally not giving explicit instructions for arranging and hanging either the conduits or electrical fixtures because everybody's situation will be different. However, they should all be fastened exceedingly securely as the conduits at least may end up supporting large weights.

*ECONOMICS*
Since I was using budget priced ($20 each on sale) fluorescent shop lights, I would have one or two a year burn out. But, I kept one or two extra around, and merely traded them out as needed. The lifespans of the fluorescent tubes was 6 months to about 3 years each. And again, I would buy them by the case of 12 on sale and keep extras handy to replace the burnt ones. I might have to replace 4 to 6 a year. So, the total, annual, parts replacement budget was something on the order of 2 X $20 (fixtures) + 6 X $1.50 (fluorescent tubes)  = ~ $49.00. (Your mileage, however, will vary.)

Annual current consumption was estimated so:

12 fixtures X 110 watts per hour X 16 hours per day X 30 days per month = ~ 635 kilowatts per month. Look at your personal electric bill to find out what you're paying per kilowatt hour and multiply that rate by 635 to estimate the monthly cost for electricity for your situation.

*PLANT CARE*
The plants were watered and fertilized as needed. Because the whole operation was strategically located next to a basement floor drain, watering was particularly easy.

In winter the basement temperature was pretty stable at about 60° to 65° F (15.5° to 18° C). In summer the temperature was somewhat higher: 70° to 75° F (21° to 24° C), but as we shall see shortly, the summer temperature was largely unimportant.

Near the end of May (Victoria Day in Canada, Memorial Day in the USA), after the threat of frost was past, I would move most of my plants outdoors, hanging them from the eaves on the north side of our home or under trees in our yard. This removal from the basement gave them an opportunity to experience daily temperature changes as well as changes in day length, neither of which was available in my basement setup. It also allowed me time for general, physical plant maintenance and cleaning.





The plants were brought in about September 1st or shortly thereafter for fear of frost.

*RESULTS*
For 20 years I successfully grew and flowered orchids, a few of them rated as semi-difficult to flower, hanging under those lights and with that care.








I also was able to grow a number of species of epiphytic cacti and a few "dirt lovers."









My setup was a low budget operation. *NO* $30 high tech, high performance tubes in $150 fixtures. No expensive, hardwired electrical work (but such would have been easily justifiable). The lighting was the only automatic thing about the whole operation. Very low key. Simple is better! I have been criticized because my setup didn't look pretty. My answer was, "I'm much more interested in the plants than I am in the furniture. One must remain focused here!"

There is no question the system worked, and worked well.

Reactions: Like 1


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## josh_r (Aug 17, 2012)

Good post


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