How Much Fluorescent is Needed Per 1000 Watts for Growing Plants?

Percentages

• Plants grown indoors will be healthier when subjected to the right percentages of fluorescent and incandescent lighting. The ratio between incandescent light to fluorescent should be about three to 10. If the houseplants require 1,000 watts of light, getting close to the target number means 240 watts should be incandescent and 800 should be fluorescent. While the combined value is slightly higher than the desired 1,000, this is the closest way to get the appropriate balance of the different types of light. Wattage is generally guaranteed when lights are placed about one foot away from the target plants.

Difference in Light Forms

• The differences between incandescent and fluorescent lights make it important to combine them properly. Incandescent bulbs are extremely hot and can generate enough heat to scald a plant; when placed far enough away that they will not dry or burn the plant, the strength of the light will be drastically reduced. To prevent this, the majority of the light should be from a fluorescent bulb. The most efficient type of fluorescent light is cool white, which will not only supply the plants with the needed amount of blue light, but will also give off some light in the orange and yellow spectrum as well. Incandescent lights give off the other form of light needed, but a lower wattage is necessary for the right amount of red light.

Determining Light Needed

• For every 1,000 watts of light about 800 should be fluorescent, but the lights don't have to be on at all times. Different types of plants require different amounts of light, and those considered low or medium light plants will thrive on between 12 and 14 hours of artificial light. Plants that thrive in high or direct sunlight can be difficult to grow indoors with only grow lights, and should be exposed to between 16 and 18 hours of artificial light. Mirrors can be positioned around the plants to ensure all sides of the plant are equally exposed.

Keeping Light New

• Fluorescent bulbs are fairly inexpensive, but will slowly fade over time. To maintain the desired wattage, fluorescent lights should be replaced as soon as the ends of the bulbs begin to dim. Without proper upkeep, the strength of the fluorescent lights will soon begin to fade.