Indoor Garden Lighting (Part 2): Choices, Choices, Choices!

Sun and Fluorescent bulb

Photo courtesy of Freedigitalphotos.net

In my prior blog I discussed the obstacles that indoor gardeners must contend with when using horticultural lighting as the primary source of light for their gardens. With those challenges of indoor garden lighting in mind, lets review what options indoor gardeners have when selecting lighting.

Fluorescent lighting comes in a variety of sizes, shapes, wattages and styles. The old standard 4’ shop light T12 bulbs (40 watt) produce about 2,600 Lumens. The newer 4’ T8 bulbs (40 watts) produce about 3,200 lumens. The preferred horticultural fluorescent lamps are T5 bulbs (54 watt) and produce about 5,000 lumens per 4’ bulb. There are also compact fluorescent lamps (or CFL) that have built-in ballasts in either 125, 200, or 250 watt options that produce about 45 lumens per watt.

Lamp Type 4’ T12 4’ T8 4’ T5 Compact Fluorescent
Lumens Per Watt 65 80 92.6 Roughly  45

The pros of fluorescent lighting are that they have relatively low wattage, can be utilized in all sorts of size areas and configurations, and they are more affordable than some of the other options. However, fluorescent lighting does not deliver the intensity of light to provide good penetration through the canopy. There are also issues with  fluorescents lacking the intensity necessary to produce fruit on high light plants. Lastly fluorecent lights give off a good bit of heat. They are an excellent choice for mother plants, clones, and young seedlings.

HID or high intensity discharge lighting has been the standard lighting for horticulture for decades. Although they produce an enormous amount of heat, they are able to provide good penetration of light through the canopy to about 3 feet. Utilizing switchable ballasts & different bulbs you can choose a spectrum heavy in blue light (Metal Halide) for vegetative growth, or heavier in red light (High Pressure Sodium) for flowering and fruiting.  HID lights are reasonably priced, they are proven as a primary or sole light source, and they able to produce enough intensity of light to allow high light plants to produce excellent crops. For more information about HID lighting, check out this helpful HID lighting guide.

Plasma Lights are a type of electrodeless lamp energized by radio frequency or microwaves. The interest in this type of lighting is driven by two factors: spectrum and the potential for financial savings (based on lower electrical consumption). The spectral output of a plasma light is almost identical to the light spectrum of the sun making it ideal for horticultural applications. Plasma lights are also capable of producing large amounts of light from relatively small amounts of electricity yet they still produce large amounts of heat. Currently there are Plasma Grow Lights available for sale made by Gavita Lighting in Holland but they are still in their respective infancy.  Based on my personal testing I will say they hold a LOT of promise.

LEDs or Light Emitting Diodes are starting to draw a lot of attention, not just from indoor gardeners but also from the general public. There are LED bulbs to replace your standard incandescent household light bulbs, LED flashlights, and even LED wallpaper. Why this explosion of LEDs, and can we as gardeners benefit from LED Grow Lights? Stay tuned to future blogs to find out.

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