Growing Orchids Under P. L. Lights

Orchid plants have been grown under high pressure sodium lamps for many years. The development of the P.L Light System, which provides a 30% increase in the blue spectrum and produces 52,000 lumens of light, has made orchid culture under these lights even more rewarding, producing better growth and more frequent flowering.


It is important to remember that footcandles as stated in books for growing orchids in greenhouses is generally measured at peak sun hours usually during noontime. This does not take into account low light levels received in the early morning or afternoon. Under sodium fixtures, light is constant throughout the day and the additional hours of this constant light add up and provide adequate light to grow the plants properly. Much of the light that is critical to the plant, i.e., far red light, is not measurable in terms of footcandles. Footcandles are a measurement of light based on the equivalent of one candle at one foot distance from the measuring device. This is based on visible light. Orchids growing under sodium light will actually grow under fewer footcandles than orchids grown in daylight measurements.


The P.L. Light best suited for orchid growing is the PL2000 400 Watt Super(Please note: this replaces the previously offered 430 Watt model.  The 400 Watt Super offers the same output as the 430 Watt but is much more energy efficient to operate). There are four different styles of reflectors: a superwide reflector for very low mounting heights (3-4 feet), a wide reflector for low mounting situations (4-5 feet), a medium reflector for midrange mounting (5-7 feet), and a deep reflector for higher mounting (8-9 feet). The typical growing area one of these lights will cover is about 8' x 8' if lower light plants are placed on the perimeter.


A key factor in determining the area that will be covered by these lights is the amount of reflective surfaces at the perimeter. If these lights are mounted in a basement area at the 7-8 foot mounting height, and if none of the walls are reflective, the areas receiving adequate light will be reduced to 6' x 6'. Placing white plastic on the ceiling and all sides of the room, or painting the walls and ceilings white, will increase the light level by as much as 30%. The plastic will keep the humidity at a higher level.


We recommend that if you are going to grow under lights in the basement, you place your growing area in a corner of the room or along one of the concrete walls. This will act as a heat sink and keep the temperatures from going too far into the extreme. The walls should be painted with a vapor seal type paint to keep humidity from working its way out of the concrete block. (Humidity can cause chips of the block to freeze and pop out.) It is recommended that either the outside of the block be covered with Styrofoam to a level about 1 foot below ground, or the inside layer of the block be treated with vapor seal paint or covered in plastic.


Because humidity rises, another area of concern is where the wooden plate meets the concrete block around the ceiling area of the basement. This area typically is colder and the warm humid air will rise and condense against the plate and cause eventual rotting. We recommend that this area be insulated and sealed off with plastic. 2" closed cell foam glued against the plate will protect it from moisture and keep the cold temperatures out.


Constructing a Growing Area

An important thing to consider is the utility of the area. When you water your plants, where will the water go? Will humidity damage anything? How can I reflect the light back into the plants where it is most needed? Again we recommend you cover the ceiling with white plastic, and either paint the walls white, or simply drop a white plastic curtain from the ceiling to floor level.


When it comes to water and drainage, there are many ways of getting around that problem. You can either grow your plants on humidity trays with water collecting underneath as you water the plants, or on benches with custom drip guards that drain into a large bucket or barrel that could be pumped out as needed. Of course, the easiest solution is to build this area over a floor drain.


Temperature fluctuations will be regulated by:

  1. the average temperature in your basement

  2. the heat given off by the high pressure sodium light

  3. any heat or cooling vents in the room


These lights will give off 1200 BTU's an hour, and should raise an 8' x 8' room up to the high 70's to mid 80's for a daytime temperature. Night temperatures should fall to whatever the normal basement temperatures are. In the hot summer months, the basement is an excellent area, as it is cooler than the outside and the humidity is higher as well. Depending on the kind of plants you are growing, the ideal temperatures generally range from 60-64 degree nights and 73-83 degree days.


We recommend an oscillating fan be mounted in the room to keep the air moving. This will help prevent fungi, mold, and bacteria from developing on the plants. It will bring more oxygen and carbon dioxide past the leaves for better growth.


If your temperatures run too warm in this area, we recommend that you simply open the door to the rest of the basement, or install a reversing exhaust fan through a window to the outside that will exhaust the heat out from the basement during warm spells or bring in cool air from the outside at night.


Fixed ballast lights come with a hanging kit and can be mounted into your floor joists utilizing two 'J' bolts that slide into a T-track on the top of your light fixture. These bolts are secured by metric nuts tightened onto the track. Two lag hooks and two chains are supplied with the kit. Simply screw the lags into the floor joist and hang the light with the chains.


Remote fixtures have a reflector that comes with two V-shaped hangers. Simply hook the hangers into the two holes at each end of the reflector and attach to two lag hooks. (Lag hooks can be purchased at a hardware store.)


We recommend you consider the size of the room that you wish to build, and remember that usually orchid collections tend to grow both in plant size and number of plants. Plan a size 1-1/3 to 2 times the size you think you need. Allow yourself the ability to expand from the beginning. One light will cover an 8' x 8' area, and two lights will cover approximately 10' x 12' area. Spaces larger than that we run through the computer to determine mounting height and distance between lights and walls in order to calculate adequate illumination.


Most light setups with P.L. lights operate at 400-500 foot-candles. This is adequate for most plants to grow properly. Plants requiring higher light can be placed in the center of the growing area or up on tiers closer to the lights from 3' to 5' away. Low to medium light plants can be placed at the perimeters.


Benching

Tiered, wire mesh benches can be purchased through different suppliers. You can also make your own out of redwood, cedar, or treated wood. Use a 2 x 4 frame with a plywood bottom lined with plastic and filled with lava rock as an extra humidifier. When constructing this bench we recommend you install a valve to allow drainage of excess water and to allow cleaning and flushing out every so often. Above this frame you should install either 2' x 4' plastic lighting grids as used for fluorescent lighting, or a wire bench mesh. You can also simply use 1" x 2" slats spaced 1" apart to allow adequate drainage and support for your plants.


Remember that when building your bench, the human reach is about 3', so don't build your benches any wider. 2-3' is an excellent size. A 6' wide bench in the center can be reached from both sides. Consider the movement you will be making in this area and lay it out accordingly. Custom rolling benches are available for larger growing setups.


Utilizing High Pressure Sodium Fixtures in the Hobby Greenhouse

P.L. Lights High Pressure Sodium Fixtures are an excellent source of light to extend winter daylight hours and provide light during periods of heavy cloud cover. Growth continues uninterrupted and flowering is faster with higher bud count.


The fixture draws 450 watts total or 4.2 amps at 120 volts, 2.2 amps at 240 volts. They produce 52,000 lumens of light. They are available in four reflector styles: medium, deep, wide and superwide. All can be wired with cord for 120 volts or 240 volts.


PL2000 400 Watt Super HPS Fixture (Fixed Ballast)---$295.00
120 Volts, wired with cord, 400W Super bulb,
with Medium, Wide, Superwide or Deep Reflector

Metal Halide Fixture (Fixed Ballast)--------------------------$285.00
120 Volts, wired with cord, 400W Metal Halide bulb
with Medium Reflector only

Remote Fixture, 400W Super-----------------------------$335.00
with Medium, Wide, Superwide or Deep Reflector

400W Super Replacement Bulb-----------------------$80.00
430W Son Agro Replacement Bulb------------------$56.00

Metal Halide Replacement Bulb-------------------------------$76.00

Shipping charges, anywhere in the continental U.S.*:
                                                        for one light-----------------$40.00

                                                        for two lights----------------$70.00
                                                   
                                            picked up at our nursery---------$25.00

                                                  replacement bulb---------------$8.00

*For Alaska and Hawaii, we will provide shipping quotes.


Reflector Specifications
Medium reflector: Designed for a more rectangular illumination field. Suitable for mounting heights over 6 feet.
Wide Reflector: Designed for a more rectangular illumination field. Suitable for mounting heights between 4 and 5 feet.
Superwide Reflector: Suitable for very low mounting heights between 3 and 4 feet.
Deep Reflector: Designed for a square illumination field. Suitable for a height of 5 feet depending on the light level required.

For Alaska and Hawaii, we will provide shipping quotes.
These lights, available in all voltages and phases, can be shipped to any destination in the world. Foreign customers will be responsible for customs fees. If you have any questions on these systems, be sure to call or write.


Our services will save you money and trouble in the long run. We have customers who have wonderful success under these lights, blooming plants that previously would not bloom, and sometimes (in the case of vandas), flowering plants 2-3 times a year. To order your P. L. Light, go to our catalog under "Equipment".

 

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