Growing Under Lights

Around this time of year, we start to feel a little wilted. We’ve lost some daylight hours, and the shorter days can take a toll on our energy levels. Our plants feel the same way! Growing plants under lights is an easy way to supplement that lost sunlight for your plants. You can keep plants indoors and still make sure they’re getting enough light to stay vibrant all season!

Choosing a Grow Light

Depending on our goals for indoor growing, there are three main artificial light options to choose from: fluorescent, HID, and LED bulbs. Each one has its own pros and cons to consider based on what kind of indoor growing you’re trying to do.

Fluorescent Grow Lights

You may remember good ol’ fluorescent bulbs from back in school when they used to hang over your little head in classrooms. As it turns out, fluorescents are as useful for young plants as they are for young humans. Fluorescent lights are great for helping seedlings and leafy greens grow indoors, but they come with a few drawbacks.

The first drawback is that they’re not quite strong enough to induce flowering or fruiting. The next is that they’re power-hungry. You need both the bulbs and the ballast to set them up, and they look…well, like school lighting.

Plants growing under grow lights indoors

High-Intensity Discharge Lights

High-intensity discharge lights, like metal halide (MH) lights and high-pressure sodium (HPS) lights, are the go-to bulbs for commercial indoor growing. If you had the inclination to grow a vegetable garden in your basement, these would be the bulbs to pick. For the average indoor gardener, however, these bulbs can be a bit much. For one, they mimic the sun in both light output and heat, which means you need to pay close attention to avoid scorching your plants. Also, while they do have the highest output of light of any of the standard options, that comes at a high cost…which you could soon see on your energy bill.

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LED Grow Lights

As Goldilocks would say, this one is ‘just right’. In the early days of LED technology, LED grow lights consisted of red-and-blue lights that did wonders for plants, but they turned your living room into a scene from a nightclub. Not everyone’s cup of tea! But LED bulb technology has improved immensely over the past few years, and these days you can get LEDs (light-emitting diodes) in an impressive range of options, all of which are highly energy-efficient!

These days, full-spectrum LED grow lights are available that are perfect for home use. They emit a pure white, natural light that looks wonderful inside your home and can be installed in decorative light fixtures. You can use them to nurture a few indoor houseplants, and they’re strong enough to encourage flowering. The only drawback is the bulbs have the highest initial cost of the bunch. For an indoor growing solution that isn’t an eyesore (or a gouge on your electricity bill), though, we’d say it’s worth it!

Tomato seedlings growing indoors

Setting Up Your Grow Light

Whether you’re using old-school fluorescents or natural-light-mimicking, full-spectrum LEDs, proper grow light setup depends on the needs of your plant. Some plants need to be closer to a light source than others.

  • Leafy plants, like philodendrons, are less light-sensitive and can live happily about 36 inches from their light source.
  • Flowering plants, like begonias, are more light-sensitive and prefer to be around 12 inches from the light source.
  • Some plants with larger blooms or plants that produce fruit need more light. They should ideally get some bright indirect light from the window in addition to an artificial light source if you hope to see them bloom.
  • Secure your lamp well to prevent it from falling on plants, which can singe them and become a fire hazard. This is especially important for clamp lights.
  • Check the distance between the lamp and the plant regularly. Plants grow toward the light and may close in on the distance more quickly than you expect. An adjustable or telescoping light fixture will make it easy to adapt the position of the light as your plant grows.
Lettuce plant under grow lights

Tips for Indoor Growing

Indoor lighting isn’t only one part of indoor growing! Here are a few more tips to help your indoor plants stay healthy:

  • Pay attention to the duration of light your plants need. Short-day plants, long-day plants, and day-neutral plants all have very different needs in terms of how long they’ll need to be under the lamp. You don’t want to go all in on indoor grow lighting, only to watch your plant die anyway!
  • Monitor soil daily and make sure your plants don’t get too dry. Plants grown under lights indoors dry out much faster than outdoor plants in the sun.
  • Keep an eye on the heat level. All grow lamps emit quite a bit of heat, even LED bulbs, which burn the coolest. Use a small electric fan to help circulate the heat if the area is reaching temperatures above 82°F.
  • To maintain humidity, make a pebble tray. Lack of humidity is a real risk when using grow lamps, especially if you need to circulate the air. Boost humidity using a shallow dish lined with a layer of uniformly-sized pebbles. Fill it with enough water that the pebbles are almost covered and sit your plant pot on the pebbles. The water will slowly evaporate and add humidity to the air.

Growing with lights requires a few changes in your usual plant care habits, but nothing the average plant owner can’t handle. While nothing is quite like the sun, indoor growing lights make it possible to keep yourself surrounded by lush greenery – no matter what the time of year!