Grow lights or fluorescent lights and what to look for

(Question)

Hi
I live in Toronto and I have some tropical flowering plants and other plants which I want to protect during winter. We have a heated basement with a bathroom which has no windows and I want to make use of this room for the plants. I do not want to spend a lot of money on lights. I have heard about fluorescent lights being used as grow lights. Are they cheaper to grow lights? Please advise me what is the best light (fluorescent or grow) for me to light my dark bathroom so as to benefit my plants? What should I look for when buying either fluorescent lights or grow lights? I would greatly appreciate your detailed answer.

(Answer)

Plants are such a joy to have indoors! They are attractive, fascinating, and keep us in touch with “nature.” Not only do plants provide us with a psychological lift, they are beneficial; they clean and humidify the air, and most importantly provide oxygen.

Sunlight has the perfect balance of wavelengths necessary for plant growth and blooming, Plants use the full spectrum for photosynthesis, although red and blue light seem to be most critical. Red light stimulates vegetative growth and flowering, but if a plant gets too much red light, it will become tall and spindly. Blue light regulates plant growth, which makes it ideal for growing foliage plants and short, stocky seedlings. Plants have little use for green wavelengths and reflect them back, which is why leaves appear green

Just as plants differ in their need for certain colors of light, they also differ in their need for light intensity. Typically, those plants that are native to tropical jungles or shady forests do not require as much light as plants that evolved in dry, sunny climates. The intensity of light that a plant receives is determined by the wattage of the bulb and by how close the plant is to the light source. Most flowering houseplants, such as African violets and begonias, are happy being 10 to 12 inches away from a light source. Foliage plants, such as ivy or philodendron, can be placed as much as 36 inches away from a light source.

No matter what types of plants you are growing indoors, you must be sure to give them a rest period fom sunlight. During the dark, plants respire which is an important part of their growth and metabolic processes. As a result, botanists have classified plants into 3 categories: Short day plants– these plants such as chrysanthemums, kalanchoe, azaleas and begonias, will thrive on less than 12 hours of light per day. Long day plants: require at least 14 to 18 hours of light each day, this would include most vegetables. Day-neutral plants: such as African violets, coleus, geraniums and most foliage plants are usually satisfied with 8 to 12 hours of light.

There are a number of types of grow lights  available, each with their own strengths and characteristics.

Incandescent lights give off a lot of heat and as a result should be placed furthest away from the plant foliage. Incandescent bulbs give off more red wavelengths, so they can be used to supplement fluorescent light and balance out the spectrum, especially if you’re trying to encourage plants to bloom.

Fluorescent lights have a low heat output and are cool enough to put close to plant foliage. Generic fluorescent tubes  are higher in blue wavelengths, so look for “full-spectrum” or include a mix of “cool” and “warm” bulbs.

Horticultural grow lights are generally packaged in tubes for fluorescent fixtures. They contain the full spectrum of wavelengths

There is an excellent article from the University of Missouri on Lighting Indoor Houseplants which gives detailed instructions on which lights are best as well as how far to place plants from your grow light.