Grow lights are usually the most expensive item in the indoor garden, so it’s important to choose the right one for your requirements. You should measure the square footage of your garden area, and consider the plants that will be grown. Different plants have different light requirements. Normally, the taller the plant, the more light required in order to reach the lower sections. Plants that flower or fruit typically require more light than those which do not (i.e.: herbs).
What type of GardenLight should you use?
Florescent lights are fine for starting seeds or cuttings, but are not powerful enough to light an area more than 8-10″ below the bulb. Although more efficient than incandescent lights, they are still much less efficient than HID light systems. HID (High Intensity Discharge) light systems have revolutionized indoor gardening in the last two decades. They are the most energy efficient grow lights available, so they produce much more light for the amount of power consumed. The American Greenhouse Kit Company offers GardenLights in MH and HPS. Metal Halide (MH) bulbs emit a light spectrum which appears blue-white to the human eye. This color spectrum is more conducive for vegetable growth, or starting seeds & clones. High Pressure Sodium (HPS) bulbs emit a spectrum which is more concentrated in red/orange light. This color is ideal for the fruiting and flowering stage of a plant’s development. It is a good multipurpose light as well. Larger wattage systems will cover larger growing areas, and since these bulbs produce greater light intensity they are superior for growing taller plants such as tomatoes.
Which GardenLight is right for you?
Most gardeners use at least 25 watts per square foot of garden space. You may need less if your GardenLight is used to supplement natural sunlight, or if you are growing a plant that does not require as much light (i.e.: lettuce). However, many gardeners prefer to double or even triple the recommended wattage to achieve faster growth rates. There is really no such thing as too much light, but using a big light in a small space will sometimes result in high temperatures that are difficult to control. Keep in mind that plants need periods of darkness too. Most indoor gardeners use supplemental light from 10-16 hours per day. Hanging Height: Keep an HID bulb about 30″-36″ above the top of your plants. (This is an average distance, lower wattage bulbs may be placed closer, while higher wattage bulbs may need to be placed further away). Higher wattage bulbs provide more intense light for large growing areas. Lower wattage systems are used for smaller garden areas Note: the height of the reflector/fixture above the plants will also affect coverage area.
Average coverage area by wattage:
150/175 watts: 2′ x 2′
250 watts: 3′ x 3′
400 watts: 4′ x 4′
600 watts: 6.5′ x 6.5′
1000 watts: 8′ x 8′ Power Consumption: On average a GardenLight will increase your electricity cost from $5 to $8 per month-the exact amount depends on the size of the system and the number of hours operated. However, since these grow lights are so energy efficient, you are getting huge amounts of light (and growing power) for your money! Make sure your grow room’s power circuit can handle the power draw. For safety reasons, do not exceed 75% of the rated ability of the fuse (for example: use no more than 15 amps on a 20-am circuit). To calculate your cost, multiply the bulb wattage X hours of operation and divide by 1000. This figure is the number of kilowatt hours of electricity consumed. (Example: a 400 watt bulb running for 18 hours will use 7.2 kilowatt hours). Check your power bill for the cost of each kilowatt hour.