Grow lights can be used in a variety of ways. They may let you grow sun-loving plants indoors or on a windowsill that doesn’t get enough natural light. Grow lights can increase the yield of an indoor garden or delay the production of fruit and foliage. Colored grow lights could let you foster leaf or stem growth over the plant’s natural growth pattern. And grow lights could foster accelerated growth of plants in their early stages. Let’s review how to grow with LED grow lights, regardless of your intended application.
Raising Seedlings and Sun Loving Plants
These are perhaps the easiest plants to grow under LED grow lights. Two hours under an LED grow light equals one hour of direct natural sunlight. The seed bed or sun loving plants are set up under a full spectrum light for 12 to 14 hours; this equals six hours of direct sunlight.
If you’re trying to maximize leaf production, 16 hours of grow light with 8 hours to rest will maximize leaf growth. There are rare cases where growing plants in a closet greenhouse leads to recommendations to run LED grow lights 20 hours a day with four hours off to let the plants rest. No plant needs 24 hours of sunlight.
Note that if you’re trying to give the plants an “off” cycle and downtime, don’t work in the dark space. The light intrusion, the little bit of outside light that comes in through an open door, will harm their growth. If you must enter the room, use green light, since that isn’t absorbed by plants.
When you’re dealing with seedlings, a fluorescent white grow light is good enough. When you’re fostering aggressive leaf growth, then an LED panel with white, red and light blue emitting diodes is better. Then you could give the plants mostly red light when they’re young and a mix of red and white light as they mature.
In short, seedlings and sun-loving plants can be treated the same way when you’re trying to grow them with LED grow lights. This includes sun-loving plants you’re keeping inside over the winter and seedlings you’re giving a head start while it is still cold outside.
Nurturing House Plants
Most plants we consider indoor houseplants are those that live on the forest floor, in partial shade or other low-light conditions in nature. This is because our artificial light or the limited sunlight that comes in through the window isn’t powerful enough for sun-loving plants. Plants that naturally grow in partial shade or forest floor need only six hours under a grow light. However, even “indoor” plants may need more light than what they get in your home. White LED lights are the best choice in these situations.
You may need to put succulents and other houseplants under an LED grow lamp for a few hours a day to foster their growth. They obviously need more light when they start to fade, stretch or turn brown. Conversely, sick plants may need red or blue LEDs targeted at weak areas to help the plant recover. For example, a plant that is losing green in its leaves or becoming “leggy” needs more blue light, since blue light will encourage the growth of stems and leaves.
If you want to nurture sick house plants or target weak areas, small LED grow lamps with flexible necks are ideal. If you simply want to give houseplants more light, an LED light panel with or without a mix of red and blue light diodes will be sufficient.
There are times when you want to use a grow light over putting the plants by the window. For example, the area by the window may be so cold that it harms the plant you’re trying to encourage. The solution is putting them under an LED grow light. Plants that grow better under cooler temperatures are probably better off inside and under an LED grow light than put out on the deck or in the hot summer sunlight streaming through the window, too.
Maximizing Production in Any Situation
The increasing red wavelengths of sunlight received as the day lengthens tell many plants to bloom for spring. The decreasing red wavelengths received in the autumn as the days shorten triggers fruiting or fall foliage. Red LED lights can be set up around indoor plants to trick them into thinking it is still the high days of summer. If you’re raising plants under fluorescent or white LED lights, you’ll need to bring in red lights at some point to trigger the flowering response in the plant.
This will keep indoor tomato plants bearing fruit. It will trick flowering plants into continuing to put out flowers. Red light will help plant roots grow and bulbs develop. Strong red light will keep plants short and leafy instead of growing tall in search of light. In every case, LED lights allow you to provide strong light without the risk of literally burning the plant because you put a too-hot bulb near the foliage.
If you’re growing plants in a small, private hydroponics unit, then a full spectrum LED grow light is best. If you’re specifically maximizing production, then the ideal case is simply red and blue light mixed together. This creates the purple light that you see in nearly every picture of hydroponic farms, whether they’re raising lettuce, herbs or tomatoes. They ignore the white light LEDs because they want to speed up plant growth once the baby plants are established. (Yes, the seedlings will probably be under fluorescent lights if not general full spectrum lights.)
If you own an aquarium with live plants in it, you can stimulate their growth by putting a small full spectrum LED grow light over the tank, turning it on for a few hours a day. If the fish tank is overgrown with algae, then you may need to turn off the lights for a few days after you’ve cleaned the tank.
The best way to grow plants with LED grow lights depends on the type of plants you’re raising, how much natural light they get, and the end result you want.