I purchased from Walmart 2, 4ft flourescent shoplights and outfitted them with 2 wide spectrum grow light on each. I raise both irises and Daylilies from seeds. The lights are hanging over 2 shelves mounted on my office wall. I have used the same outfit for 4 years and the tubes are still good. When the edges of the tubes begins to darken, it is time to replace them. I use a timer of for 16 hours/day.
Here is some info that I came across.
ABOUT LIGHTS
All fluorescents are not the same. Grow lights are made up of wavelengths within the red, orange, yellow, green, blue, green, and yellow of the spectrum that are suitable for plant growth that incandescent bulbs don't have. Plant lights are made to resemble full sun very closely and contain the wavelength in colors that plants need to grow. I don't want to get too technical so the above info is a short explanation.
The watt is usually related to the length of the fluorescent bulb. A 48" long tube will produce more light than a 24" one. The only information you need about a fluorescent light tube is that it is a grow light in whatever length you want.
You actually need 2 grow tubes placed side by side with 2-3" from each other in whatever lengths you choose. The reason is that there is a light fall off along the sides of the lights that is not strong enough to support plant growth. The strongest light is in the center. Place your sun loving varieties there and shade lovers more on the outer side. You can increase light at the edges by placing a large, white paper mat or board held up along the edges to reflect the fall off light back on to the plants.
HOW CLOSE? HERE IS A GUIDE:
This guide is suitable for plant lights, not for incandescent light. Measured from the top leaf.
Annuals, perennials, herbs, and vegetables---3-6" from the light
Geraniums---4-6"
Begonias---6-8"
Cactus and succulents---3-6"
Impatiense---5-7"
Observe your plants, if not enough light the plant will stretch upwards. Move them closer.
HOW LONG
Use a timer, cheap in Wal-Mart. When seeds have sprouted, they need 12 to 16 hours of light for flowering plants. 12-14 hours for foliage plants. The light should be on at the same time every day, thus a timer is useful incase you forget.
It is not worth it to skimp on pennies regarding grow lights when you are raising plants from seed.
AIR CIRCULATION
Very important to prevent damping off (rotting) of seeds and fungus. Also to bring carbon dioxide that the plants need for photosynthesis during the day and fresh oxygen which they need to breathe during day and night. You need mild air movement, without a cold draft. A small fan set on low will work.
TEMPERATURE
Once the seeds germinate, it is best to grow plants between 65-70 degrees for sturdy seedling. More beneficial is to have a lower temperature when the lights are out at night.
Below are my 2 shelves. Photos are mine.
Sue
