From Gardener's Supply (www.gardeners.com)



LED Grow lights are perfect for indoor seed starting, as well growing as light-loving houseplants, such as orchids.

With a set of grow lights, you can grow many plants indoors, including houseplants, orchids, and even some fruit and vegetable crops. Grow lights are ideal for seed starting because they help ensure stocky, green seedlings. A wintertime harvest of herbs and salad greens can also be grown under lights. By learning how plants use light and about the fixture options, you can select an indoor grow lights system that is right for the plants you want to grow.

The Right Color

Sunlight contains the complete spectrum of light including all colors of the rainbow: red through yellow to blue and violet. Like plants growing outdoors in the sunlight, indoor plants grow best under full-spectrum bulbs, which produce a balance of cool and warm light that replicates the natural solar spectrum. They're excellent for seedlings as well as houseplants, culinary herbs and other plants. All of our grow light fixtures, stands and replacement bulbs are full-spectrum.

LED or Fluorescent? Both produce full-spectrum light. However, LEDs are better for the environment and your wallet. Our product development team has engineered energy-efficient, economical and effective LED lights to specifically meet the exacting needs of plants (in contrast to multi-purpose LEDs). They deliver the bright, full-spectrum light plants crave, with an additional spike of blue light to stimulate stronger root growth, enhance photosynthesis, and ensure peak growth. Enjoy your heartiest and healthiest seedlings, houseplants, orchids and other indoor plants! They're great for your plants. High-tech LEDs are calibrated specifically for indoor growing.

High-tech LEDs are calibrated specifically for indoor growing. They're super-efficient. LEDs use half the electricity and last 5x longer than fluorescent bulbs.

LEDs use half the electricity and last 5x longer than fluorescent bulbs. They're earth-friendly. Mercury-free LED tubes won't shatter like glass, so fewer end up in the landfill.

The Right Intensity

Our Vermont-made SunLite Gardens are available with either LED or fluorescent bulbs.

The intensity of light that a plant receives is determined by the brightness of the bulb and by how close the plant is to the light source. Plants 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, such as the Mediterranean or southern Mexico.

Some 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. But many flowering plants, such as orchids, gardenias and citrus, as well as most vegetable plants, require a much higher light intensity to flower and produce fruit.

The Right Duration

No matter what types of plants you are growing, you must give them a rest. When it's dark, plants respirate, which is an important part of their growth process. The balance of rest time to active growth time affects many biological processes, including the growth rate, and the setting of buds and fruit. A power strip with built in timer makes it easy to get the duration right.

Vegetable seedlings need 14-18 hours of light a day.

Botanists usually divide plants into three categories relating to their preferred day length: short-day, long-day or day-neutral.

Short-day plants, such as chrysanthemums, kalanchoe, azaleas and begonias, will thrive on less than 12 hours of light per day. In fact, these plants must usually go through a series of even shorter days before they will set buds and flower.

Long-day plants require 14 to 18 hours of light each day. Most seedlings for vegetables and garden flowers are long-day plants. When they don't receive enough light they get pale and leggy.

Day-neutral plants, including foliage plants, geraniums, coleus and African violets, are usually satisfied with 8 to 12 hours of light all year-round.

What are LEDs? LEDs (light-emitting diodes) create light when an electric current — a flow of electrons — passes through a special material called a semiconductor. As the name implies, a semiconductor allows some, but not all, of a current to pass through. Crystals made of pure silicon don't conduct electricity. But when a small amount of an additional substance such as phosphorus is introduced into the crystal, it upsets the equilibrium of the material and activates the electrons inside. When an electrical current is applied to the crystal, some of this activation energy is released in the form of light. NASA pioneered the use of LEDs for growing plants as a result of their research on the best lighting technology to produce edible crops in space.