When we first moved into our condo in Chicago, we loved everything about it — everything except the natural light. We were actually lucky to have good-sized windows that, in theory at least, would flood the living room with bright sunlight. But living in a city combined with the shorter daylight hours in Chicago's winter meant fewer hours of sunlight for us — and our indoor plants.
So what to do when natural light doesn't abound, but you still want the benefits of indoor plants — be they edible, decorative, or functional? Enter grow lights.
Grow lights are indoor bulbs that can frequently be put into normal light fixtures, or into specialty structures, to supplement a plant's growth when there isn't enough natural light indoors. In fact, these lights are actually more beneficial than natural sunlight because you can tailor the kind of light to where the plant is in its growth cycle.
Grow lights come in blue, red, or white, and correspond to different needs of the plant. Blue lights have a color temperature of 5000 Kelvin or higher and help your plant to grow during the vegetative stage. Red lights have a color temperature of 2000 Kelvin and help your plants during the flowering stage (i.e., once they've already started to produce buds). Or you can get the best of both worlds with full-spectrum fluorescent bulbs, which combine cool and warm light to create white light and come in a temperature range of 2700 to 10,000 Kelvin.
LED vs. Fluorescent
Grow lights are not new. Greenhouses have been using heat lamps and fluorescent lights to help accelerate seed germination and plant growth for years. What is new is the use of LED lights for plant growth. These newer LED lights are small and compact, super easy to use, and combine both red and blue light to achieve the best combination to help your plants through the entire growth cycle. Plus, they make your plants look a little trippy.
Although there are more intense structures available for the hardcore indoor grower (fair warning: most look more meth lab than Martha Stewart), most LED bulbs can be purchased individually and used with an adjustable clamp — no heavy machinery required.
For those less inclined to a plant disco aesthetic in their living rooms, another option is full-spectrum fluorescents. These bulbs produce both warm and cool light rays at a rate of up to two times that of incandescent bulbs — and for the same amount of energy.
Because the bulbs are often rods and need special outlets, fluorescents frequently require a supportive structure like the SunLite system, which has the advantage of allowing you to adjust the distance between the lights and your plants as growth continues. The Click and Grow system for herbs and edibles is another great option for those wanting to let technology take care of the light management.
The Best Plants for Grow Lights
Almost all plants benefit from a little extra light. Most houseplants need a minimum of six hours of sunlight a day in order to flourish — so, if your home offers less than that, grow lights are a great option to boost your growth potential.
However, many plants need much more than six hours, and grow lights are most beneficial for light-hogging plants like orchids, tropical flowers, and edibles. Grow lights are also ideal for starting seeds indoors in the winter, when up to 14 hours of light may be required. Be sure to check the lighting requirement for your plant.
How to Position Grow Lights
The type of plant you are trying to grow, and what stage it's at in its life cycle, will determine the position of the lights. Flowering houseplants like orchids need 10 to 12 inches of distance in order to flower, while foliage plants can be between 24 to 36 inches away from your light source. Think, too, of the plant's native climate when positioning your light: If the plant is from a shady location, greater distance from the light is required; plants that grow in sunny climates require closer positioning.
If you're starting seeds indoors, you want your grow light close — about 10 to 12 inches away from the top of the soil. As your seedling grows, raise the light once a week to maintain about a foot of distance. For encouraging the vegetative stage (i.e., after the seedling is established), the lights can be positioned farther from the top of plant canopy — up to 36 inches, depending on the plant.
How Much Light Do Your Plants Need?
As counter-intuitive as it may seem, just as important as the amount of light a plant receives is the amount of shade or darkness the plant receives. It is during this time that the plant recuperates — think of this as a plant's "sleep" time. Your plants (especially seedlings — just like kids) need at least six to eight hours of darkness for healthy growth.
A good way to manage this is to either keep your plants on the same sleep cycle as you and turn on the lights in the morning, or if your light setup allows for it, keep your lights on a timer.
As always, there's some trial and error involved. As science-forward as grow lights may seem, they are just lights, and these are just plants that you're growing. The best advice for growing plants isn't necessarily what's on the plant package or your bulb's directions. Look at your plant, learn from your observations, and adjust accordingly. And most importantly, don't be afraid to get your hands dirty.
(Image credits: Abbye Churchill)