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Here Comes the Fake Sun – How to Use ‘Grow Lights’ for Indoor Gardening

If you want to thrive indoors, you’ll need to help them out with grow lights. Learn the basics below and give your indoor garden some much-needed light!

Why Use Grow Lights?

Plants don’t ask for much. A little water, some nutrient-rich soil, and sunlight. Without sufficient exposure to the sun’s rays, plants can’t perform photosynthesis and will pretty quickly starve to death.

Many houseplants will be fine if placed near a window. However, if you’re going to grow more challenging plants, start seeds indoors, or plant an indoor food garden, you’ll need to find another way to give them the sunlight they need.

What Type of Bulbs Should You Use?

Artificial lights—even the bright lights in your kitchen—don’t provide the right intensity or spectrum to help plants grow. But there is a special category of grow lights that will do the trick.

Grow lights fall into 3 basic categories: Fluorescent, LED, and HID.

Full-spectrum fluorescent grow lights are widely available and usually pretty cheap. However, if you’re serious about growing plants indoors, then you probably want to invest in a more robust lighting system.

LED grow lights are pricier, but they’re more energy-efficient and last longer than fluorescents. They also don’t produce much heat, so they’re a great option if you plan to install a large array of lights to grow an indoor garden.

HID grow lights have a lot of drawbacks compared to LEDs—they’re even more expensive, use more electricity, and produce more heat. However, they also get the job done. If you want to fine-tune your gardening efforts, you might want to look into using both high-pressure sodium and metal halide HID lights to grow your plants indoors.

Understanding the Science

Light waves fall on a spectrum that includes visible light, infrared, and ultraviolet. Plants need a specific range of that spectrum to grow, in varying intensities depending on their specific needs and the growth cycle they’re currently in.

You might see grow lights labeled with a number followed by a K. The smaller the number (3000K, for example), the warmer the light. Most foliage plants will thrive in light that’s around 6500K (a very cool, blue light), but fruits and flowers need to be exposed to warm light if you want them to produce.

While you might be tempted to use the highest intensity bulbs you can find 24/7 to get the biggest plants possible, that’s not quite how things work. Plants need a certain amount of time in the light to begin producing flowers or fruits. If you push them too hard, you might actually find that they don’t thrive as much as you hoped.

Installing Grow Lights

Generally speaking, grow lights should be on an automatic timer so that you don’t have to worry about turning them on and off. Most plants need 12-18 hours of artificial light to grow. Remember, they also need some downtime to rest, so don’t leave the lights on all day and night.

You’ll need a way to raise the lights over time as the plants get bigger. Many lights already come in a large, rectangular array with a system in place for raising and lowering. Fluorescents need to be really close to the plants—anywhere from 3-12 inches away. LED lights should be between 12-24 inches from the plants, while HID lights can be up to 60 inches away.

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