How To Use Grow Lights for Indoor Plants

How To Use Grow Lights for Indoor Plants

Between limitations from your homeowner's association, unpredictable weather patterns, and poor soil, it's not always easy to garden outdoors. Yet growing inside eliminates the chance to use natural sunlight for free.

Instead, indoor growing fans must provide their own mini-suns in the form of grow bulbs. Everything matters from the type of bulbs to the exact color spectrum released by them. Regardless of what you plan to grow inside your home or apartment, these tips will help you choose the right grow lights for healthy and rapid plant growth.

When You Can't Use Natural Light

The sun is the best source of light for plants because it provides a full spectrum of colors and UV rays. Plants need both UV-A and UV-B rays ideally to fight off diseases and produce the healthiest flowers and fruit. You might think you'll be able to grow plants near a convenient window and that'll provide enough light.

However, even plants with the lowest light requirements will still grow spindly and may not produce under these indoor gardening conditions. It's essential to invest in a supplemental fixture and bulb as a proper light source.

Each plant varies in the specific lumens or wattage needed, so look up the average needs for each plant you want to grow and add the amounts together to get the right lights. Expect to provide a lot of light unless you're growing houseplants like Silver Queen pothos and peace lilies.

For hemp, lettuce, or hydroponic tomatoes, you'll need hundreds of lumens or dozens of watts per plant, all packed within your indoor growing space.

Hours of Light

You need to consider more than just the raw amount of light you're providing your plants with at any moment of the day. The period of light each plant receives throughout the day determines its rate of growth and sends signals on when to switch from growing new leaves to flowering and fruiting.

Without careful control over the amount of light supplied per day, it's impossible to get most houseplants to bloom or to keep marijuana moving through the flowering stages. Timers are the best choice for controlling the number of hours of light supplied to your indoor garden.

There's no need to worry about forgetting for a few hours and throwing an entire growth cycle out of sync.

Types of Fixtures

There's no universal grow light, so you'll need to pick a type of bulb before shopping for the matching fixture. Many grow bulbs aren't sold separately from their ballasts and fixtures anymore but come as an integrated single fixture instead.

This is most common for affordable and compact fluorescent bulbs used for short-term seed sprouting and low-demand houseplant cultivation. Whether you buy a complete fixture or need to order bulbs separately, here are your main options for effective home grow lights.

  • HID Grow Lights: High intensity discharge (HID) bulbs are ideal for high demand indoor gardening plants like tomatoes and hemp. Some of the most popular types include High Pressure Sodium (HPS) and ceramic metal halide (CMH). HID bulbs put out the most light and offer a wide spectrum that can include UV rays. Unfortunately, most also generate a lot of heat that can damage plants when placed too close to leaves.
  • Fluorescent Grow Lights: For less demanding houseplants and indoor salad growing hobbies, fluorescent bulbs are a good choice. While they'll cap out at a few hundred watts each, these bulbs produce little heat and are easy to fit into any space.
  • LED Grow Lights: LED grow lights give you the most control over the exact color spectrum of light reaching your plants at any time. If you need to switch from a vegetative light color to a flowering and fruiting trigger spectrum, you may want to at least mix a few LED grow lights into your plans. They're also very energy efficient and produce even less heat than fluorescent bulbs.

Light Colors and Stages of Growth

Choosing to grow plants indoors leaves you responsible for sending the signals that tell many plants when to switch growth patterns. Without a change in the hours of light, the color spectrum, or both, many plants won't start flowering or developing fruit.

Most grow bulbs only offer one fixed part of the color spectrum, thus leading to many indoor lights being categorized as either warm or cool. High-quality grow lights go much deeper in what's actually known as the photosynthetically active radiation (PAR).

We can see some of the spectrum of PAR as either warm or cool colors like red to blue, but much of the light used by plants is invisible to us. The best grow lights will explain exactly what part of PAR is supplied so you can fine-tune your lighting solutions to your indoor gardening plans.

In general, warmer and redder lights are used for healthy flowering and fruiting. Cooler spectrums are better absorbed by plants in the vegetative growth stage. Of course, there's a lot more to consider if you want to target the exact PAR range needed by your desired indoor crop.

Need help narrowing down your options or finding the right spectrum of light? Our expert team here at Taproot Hydroponics and Organics is always ready with advice.

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