Artificial lights make it much easier for your plants to survive the low-light winter days, especially in Maine. Properly setting up artificial lighting is almost as important as having the light in the first place in terms of getting the maximum benefit to your precious plants.
When choosing artificial lights, one factor to consider with respect to setup is the size of your lights. Ellie Longfellow of Longfellow’s Greenhouses in Manchester said that the size of the lights that you choose will depend on your plants. Longfellow said that for smaller plants it can be more convenient to have the tabletop or clip-on lights, as they are more compact and can often be adjusted in their positioning. The larger scale lamps make more sense for larger plants or large groupings of plants.
Once you have paired your lights with plants, then you have to make sure that your plants are getting as much of that artificial light as possible. Hanging the lights over your plants, Longfellow said, is the best option.
“Best placement is overhead, as that will maximize the amount of plant covered,” Longfellow said. “This mimics the natural sunlight from overhead.”
The distance that you should keep your lights from your plant depends on both the light and the plant.
“Fluorescent and LED lights have a lower heat output, so they can be placed anywhere from a few inches to 12 inches roughly overhead for plants,” Longfellow said. “[That’s] a general rule of thumb for what has been found to be successful. Adjusting the placement as plants develop is also important to maintain distance. Generally, grow lights will have specific directions based on the make and model that can also be beneficial, as they really all can be different.”
When it comes to the plant, some light-loving plants prefer to be closer than others to their source of sun.
“[Cacti and succulents that] like bright light could be closer to the light whereas a fern or a jungly leafy plant might like to be further away from the light,” said John Sundling, owner of the Plant Office in Portland.
For more precise placement, Sundling suggested using a light meter app like Lux Light Meter, which can be downloaded directly to your phone. The app helps you compare how much light you are getting in different parts of your house.
Once you have your artificial lights, you will also need to make sure that you keep them on long enough during the day. Different plants will have different light requirements.
“For plants that need bright, direct light, a light could be used for 8 [to] 12 hours,” Longfellow said. “For medium light plants, anywhere from 4 [to] 6 hours. Low light plants generally don’t need a grow light but could benefit from 2 hours a day.”
Crops that you are growing to eat may need more light than decorative houseplants.
“Think about it: I have an umbrella tree that grows at the bottom of a jungle versus a lettuce plant that grows sitting out in a field,” Sundling said. “[For a] production crop, you might need to change the lights during the day to get one stage of growth to another to mimic how the light changes throughout the season. There is a lot more specific care and timing that goes into crops generally than just your general houseplants.”
Setting the lights on a plug-in timer will help you to maintain a schedule for your plants.
“Without that consistency of lights coming on every day [and] lights coming off every day, [it’s] not going to do as much good as if you’re turning it on for a few hours every day,” Sundling said.
Sundling passed along another tip: keep plants out of the room where you are sleeping, lest you are woken up by the light flickering on every morning.
Longfellow also warned not to overdo it with lights.
“Plants naturally need darkness, as that is part of the growth cycle and natural environment. Leaving a grow light on for 24 hours will do no good,” Longfellow said. “Determining the amount of light needed really is specific to an individual plant’s growing needs.”