Wednesday, November 9, 2011

World Seed Supply's Cheap and Simple Lighting Options for Indoor Plants

People ask us all the time about lighting for their indoor plants.  The following information will just offer three lighting solutions for indoor plants that most people should have access to and be able to afford.

While most serious plant setups use high pressure sodium (HPS) or metal halide bulbs (MH), most plants can be supported just fine under fluorescent lighting.  What's even better is that fluorescent bulbs can be bought cheaply and are inexpensive to run.  The most accessible and efficient form of fluorescent lighting is the CFL or compact fluorescent light bulb.  You can find these bulbs anywhere that sells light bulbs from grocery store to pharmacies to hardware stores. We've seen them as cheaply as one dollar.  And while HPS and MH bulbs require special ballasts, compact fluorescent light bulbs can fit in any standard lamp fixture as they are.  You can use these bulbs either by themselves or to supplement window light for plants.

One of the best ways to make the light accessible to your plants is to use desk lamps with bendable necks. This will allow you to adjust the lamp to fit the growth of the plants or to point the light at a particular area.  CFL lights work well for starting cactus and plant seedlings as well as for maintaining mature plants.  The following example is one simple setup using CFL light bulbs in a floor lamp / desk lamp combo.

Another source of fluorescent light is the fluorescent tube.  These are the typical lights you will find in office buildings and other public places, and they are used because they are inexpensive to run.  This setup will be a little more expensive, but it can support more plants than a CFL and will offer them much more light for good growth.  Whereas the CFL system is more for sustaining plants, the tube setup can be used for actively growing plants and seedlings.  The tubes require a special fixture which typically fits 4ft. fluorescent tubes.  Most fixtures will hold 2 or 4 of these bulbs.  

The tubes also range in thickness (from .25" to 1.5").  Thickness is based on a "T" scale from T2-T12. The T stands for tubular, and the number represents eighths of an inch.  The different bulbs have different advantages.  The T8 is the typical bulb with 8/8" or 1" diameter and will suffice for most vegetative growing situations.  So all the fancy numbers aside, a four-foot long, one-inch thick bulb will work for your basic setup.

Aside from bulb length and thickness, you must also select from light color appearance. This is based on the color spectrum of the light that is produced.  Color appearances include warm, neutral, cool white, natural light and daylight.  It should be noted that warm is just the color of the light. Warm bulbs actually run the coolest with the daylight bulbs outputting the most heat.  Many growers use the cool white bulbs for their plants, although the daylight bulbs are even better if you can find one.  

The advantage of using this system is that the fixture can be hung above the plants by chain or rope and raised as the plants grow.  This allows you to maintain the same light intensity as your plants grow without the plants touching the bulbs.  Fluorescent lights do run very cool compared to other types of light, but they can still burn leaves if the bulbs are touching them.  

The hanging system is typically employed inside a growing chamber or in places where there is something to hang the light fixture from.  But small mini chambers can be set up anywhere using plastic storage containers.  In this case, the cool output of the fluorescent light allows the bulbs to be rested on the edge of the storage bins.  As a precaution, the setup can include small pieces of wood to rest the bulb on so that it is not actually touching the plastic.  But the setup is really as simple as placing a tube fixture (two or four tubes) across the top of a large storage bin with two pieces of wood (if you choose) between the edge of the bin and the bulbs.  If you choose to skip the wood just do some tests to make sure the heat of your bulb is compatible with the plastic in your setup.  This particular example does not use the wood, and there is no damage to the plastic.  For maximum efficiency, the inside of the bin should be lined with aluminum foil (dull side out) or mylar.  But this picture shows just the minimal version of this setup.  It should also be noted that the cover of the bin is typically laid over the top of the fixture to keep light from escaping.  The overhanging areas of the bulb are also being utilized to grow cactus seedlings and root pereskiopsis cuttings.  Use the biggest bins you can find to minimize overhang.

The last setup we would like to share actually involves a specific bulb we were fortunate to come across.  It is made by General Electric and is called the Reveal 100.  This 100 watt bulb outputs 1275 lumens and is a full-spectrum bulb.  The full spectrum is what is important.  We usually buy them at Home Depot for under $5, and they are warrantied for 2 years. This bulb is enough to support a large number of plants.  We've fitted ours into a standard closet light fixture to support shelved plants.  

The only drawback about this type of bulb is that is has a very high heat output.  But it is also valuable in creating an environment for tropical and desert plants. The high output means that only very heat tolerant plants such as certain cacti can be placed close to the bulb on the top shelf.  (The small pot on top contains a small astrophytum myriostigma.)  We've even laid a screen across the top shelf for shading.  But this setup will still support plants up to five or six feet away.  Accordingly, we have plants on three lower levels of shelving, spaced 18" apart.  You only see the top two levels in the photo.  You can see some kratom plants and some Blue Agave being grown happily in this setup.  Much of the growth for the kratom, which enjoys a lot of light, occurs outside of the shelving area in the open light.  But the screen on top allows for plants that require a bit more shade to be grown underneath the shelving area.  The different levels also allow you to work with different levels of light intensity depending on what you're trying to grow.  We've also setup an upside down tub on the floor of the closet to fit additional plants.  While the other setups we mentioned involve moving the light to change intensity, this system, with a fixed light, requires you to shift the plants to access different light intensities.  Again, this setup would be most efficient if the walls were lined with aluminum foil (dull side out) or mylar.  But do what we say, not what we do : ) 

If you do not have a free closet to designate to your plants, you can still keep the Reveal 100 full spectrum in mind as a lighting option.  Feel free to adapt ideas from the section on CFL lights.  You can position your bulb using a desk lamp or other type of clip lamp.  This type of bulb will support more plants than your CFL in a similar setup.  But also keep in mind that it will produce more heat. Consider what it means for what plants will do best and what might become a fire hazard in your surrounding area.  Whereas the closet fixture is already set away from anything else, you want to be sure when using a desk or clip lamp that you do not let the bulb touch anything that could potentially ignite.

At this point, we hope that you have at least one lighting option that fits your budget, your growing space and your plant collection.  Keep in mind that these are just the basic setups for people looking to support their plants indoors.  The more you are dedicated, the more you can tweak these ideas to maximize your conditions.  This includes setting up light cycles, ventilation, humidification, carbon dioxide treatment and more.  But we'll save these topics for future guides.

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