2.  HIGH PRESSURE SODIUM LAMPS - These lamps are red/orange in the spectrum. They are the best lamps available for secondary or supplementary lighting (used in conjunction with natural sunlight). This" type of light promotes flowering/budding in plants. It is ideal for Greenhouses/Commercial growing applications.

3.  CONVERSION LAMPS - There are two types:

          A.  Sodium Lamps which run on halide ballasts - more common.
          B.  Halide Lamps which run on sodium ballasts.

This type of lamp allows you to tailor the light source to the growth stage of the plant (again using halide blue light for growth and sodium red light for flowering/budding) merely by changing lamps.

4.  FLUORESCENT - This type of light is perfect for starts and seedlings but is a poor light source for growth and budding primarily because of low lumen output.

5.  INCANDESCENT - Does not require a ballast. These lamps consist of Sylvania Spot Gro R-30 and R-40 flood lamps available in 75 watt and 150 watt. Also good for starts and seedlings. Good lamp for individual plants or small groups of plants. Provides an inexpensive alternative to HID lamps (Halide and Sodium lamps are referred to as High Intensity Discharge Lamps).

Information about Lamps

The plant sensitivity curve for photosynthesis has its peak at the red end of the spectrum (675nm) (McCree).

This chart indicated that providing plants with the wavelengths best suited to photosynthesis, is the most efficient use of artificial light. Tests show a mean deviation from the average sensitivity curve of less than 5% for a wide variety of plants. The curve shows that the maximum sensitivity for photosynthesis lies in the far red at approximately 675 nm.

The plant sensitivity curve disputes two common misconceptions. The first is that an "ideal" plant growing lamp duplicates the spectral energy distribution of the sun. Sunlight has a continual spectrum, radiating energy in wavelengths that contribute less to photosynthesis, and are therefore "wasted" on the plant. For this reason, many lamps are more efficient than sunlight for plants.

Which Lamp is Best for Your Growing Needs?

Metal Halide Lamps This type of light is blue-orientated in the spectrum. It's the best type of light to be used as a primary light source (if little or no natural sunlight is available). This type of lamp promotes plant growth.

High Pressure Sodium Lamps These lamps are red/orange in the spectrum. They are the best lamps available for secondary or supplemental lighting (used in conjuction with natural sunlight). This type of light promotes flowering/budding in plants. It's ideal for Greenhouse/Commercial growing applications.

Conversion Lamps There are two(2) types of conversion lamps:

This type of lamp allows you to tailor the light source to the growth stage of the plant (again, using halide blue light for growth and sodium red light for flowering/budding) merely by changing lamps.

Fluorescent This type of light is perfect for starts and seedlings but is a poor light source for growth and budding primarily because of low lumen output.

Incandescent Unlike the other lamps, above, this type does NOT require a ballast. These lamps consist of Sylvania Spot Gro R-20 and R-40 flood lamps available in 75 watt and 150 watt sizes. Also good for starts and seedlings. Good lamp choice for individual plants or small groups of plants. Provides an inexpensive alternative to HID lamps.

Note: Halide and High Pressure Sodium are referred to as "High Intensity Discharge" (HID) Lamps.