Early-spring bedding plants can be successfully grown indoors by using artificial light sources. The initial decisions of choosing lights and temperature may appear complicated but don’t be discouraged. After selecting a few basic lights, the remaining steps develop into an enjoyable “learn-as-you-go” experience, similar to most garden ventures.
Artificial lighting comes in a mixture of different wavelengths of light. A complete balance of light is sunlight, which includes the spectrum of the rainbow. Grow lights closely resemble the sun’s spectrum, and are ideal for starting seeds and growing plants, and flowering houseplants such as violets do well under them.
Incandescent lights (most household light bulbs), give off shades of the rainbow’s red light that is important for plant growth and formation of buds and flowers, yet they lack the essential, blue, and the high heat emitted off household bulbs is more dangerous to work with than traditional fluorescent lights.
Energy-saving Warmlite and Coolite fluorescent bulbs produce excellent short, stocky bedding plants beneath the blue spectrum of light, but they do not have enough red light to produce an abundance of flowers.
High-intensity discharge (HID) bulbs are not economical for home gardeners and are used mostly in large commercial buildings, where high light is necessary. They are expensive and need a heavy electrical system for additional safety. HID lighting often develops more leggy, stretched plants.
My choice of lighting is a mix of Coolite fluorescent and grow lights. The lesser heat released from these bulbs make them more suitable to place plants closer to the light without burning the tiny leaves, while supplying enough light spectrum to grow stocky, healthy bedding plants within a few months.
Plants need rest along with light. Tuberous begonias need at least 14 hours of lighting each day to grow ample, healthy foliage before the plant begins to form tubers. Without enough strength in the top growth to feed the tubers, the plant will quickly die. Geraniums and other sun-loving plants will require a day length and intensity of candle light that closely resembles the sun to form blossoms yet not become tall and straggly. Timers are useful for accurate timing.
As the seedlings advance they will require thinning and must be transplanted into a basic soilless mix, along with additional weekly liquid fertilizing according to package instructions. When spring weather permits, move the seedlings to the greenhouse or into cold frames to become more acclimatized before planting in the garden.
The act of supplementing daylight with indoor lights during the shorter days of winter not only produces superior bedding plants, but leads to a more advanced hobby for gardeners awaiting spring. Thoughts of early tomatoes are reason enough to “turn on the lights.” – Lillian Deedman writes
from Killarney, Manitoba