Grow Lights for Houseplants and Indoor Gardening: An Overview

Indoor cultivation offers many advantages. The biggest advantages are the most obvious: garden pests can’t reach your plants and you have complete control over the weather.

Still, unless you’re lucky enough to have a sunroom or greenhouse attached to your house, providing enough light for your plants will likely be a hindrance (with the exception of shade-tolerant houseplants). ). South-facing windows can provide enough light for a seedling tray or two, but if you want to grow vegetables or any other sun-loving plants to maturity, you’ll need grow lights.

The indoor lighting found in most homes does little to promote photosynthesis. Traditional incandescent bulbs don’t have the proper light spectrum, or intensity, to outcompete the sun. Household fluorescent bulbs can make effective grow lights, but only if placed a few inches from foliage and left on for 16 hours a day – which isn’t ideal.

Warm vs Cool: Understanding the Color Spectrum in Grow Lights

When shopping for grow lights you will notice that they are labeled with numbers like 2700K or 4000K. This refers to their relative warmth or coolness on the color spectrum – the higher the number, the cooler the light. Foliage growth is generally best around 6500K, although many plants need a warmer light period, around 3000K, in order to produce flowers, and therefore fruit.

In other words, if your goal is simply to grow seedlings, leafy greens, or roots, you only need higher spectrum bulbs. If you want to grow flowers, marijuana, or any other fruit-bearing plants (cucumbers, tomatoes, peppers, lemons, etc.), you will also need low-spectrum bulbs. You can some types of bulbs are available in full spectrum shape, however, simplify things.

Types of grow lights

There are three main types of grow lights.

Full-spectrum fluorescent lights — either of the tube or standard CFL variety — are an excellent choice when starting seeds indoors. PHOTO: By Falcona /

Fluorescent grow lights

The standard fluorescent bulb, commonly referred to as a T12, produces decent grow light for indoor plants, starting seeds, supplementing natural light from a window, and other situations where lighting needs are modest. However, their light intensity is quite low and must be placed a few centimeters from the foliage to have a significant effect.

, which are narrower in diameter than T12s (but still widely available wherever bulbs are sold), have a much higher light intensity, making them suitable as a sole light source for sun-loving plants. Compact fluorescent light bulbs (CFLs) are an option for small spaces, or if you don’t like the look of long rectangular fluorescent fixtures, CFLs screw into a regular incandescent fixture.

Find specialists full spectrum fluorescent grow lights (like that Where that fits into a standard outlet) to provide the right balance of light for flowering plants.

led grow lights

Although considerably more expensive than fluorescent bulbs, LEDs use half the electricity and last five times longer, more than they pay for themselves in the long run. The average hardware store LED bulb isn’t designed for plant growth, though – you need special a relatively new technology that is increasingly available from horticultural suppliers.

LED grow lights are capable of much higher light intensity than fluorescent bulbs and are available as a full spectrum. A simple rule of thumb: fluorescent bulbs are often used when growing a handful of plants; LEDs are better for large quantities because you can get higher light intensity per square foot. Another advantage of LEDs? They produce very little heat compared to other bulbs – an issue that can become problematic when you have a lot of lights in a small space.

HID grow lights

Before the advent of LED grow lights, were the main option for large indoor plantings. They are extremely powerful, but expensive to purchase, use electricity inefficiently, require special light fixtures and give off a lot of heat. That said, they are very effective and are still widely used. If you want to grow tall plants like tomatoes or lemon bushes, HIDs are a good bet because the light penetrates farther into the foliage than with other bulbs.

There are two types of HID bulbs. High pressure sodium (HPS) bulbs are best for flowering (low spectrum), while MH (metal halide) bulbs are needed to support vegetative growth (high spectrum); the two types are often used together. Unfortunately, each type requires its own fixture.

How to install grow lights

Installation requirements vary greatly depending on the extent of your indoor garden and the type of bulb used. But here are some basic steps to get you started.

Determine the number of bulbs you need.
Most edible plants require at least 30 watts per square foot, but fruit-bearing species (like tomatoes) generally won’t produce bountiful, high-quality crops without 40 to 50 watts per square foot. The wattage is always indicated on the bulb packaging. Simply multiply the square footage of your growing area by the number of watts you plan to supply (between 30 and 50); then divide by the number of watts provided by the bulbs you plan to use.

Design a lightweight support.
You will need a way to support the bulbs above the plants at the correct height. And unless you’re growing something that will stay more or less at the same height throughout its lifespan, you’ll also need a way to elevate the light stand as the plants grow. grow. This is usually accomplished through some sort of pulley system or by hanging the fixtures with a metal chain – this way you can easily adjust the height by changing the link from which the fixture is home. are also available for purchase online.

Add the necessary accessories.
He is Generally wise to plug your lights on a timer to ensure they get the right amount of light and get it at the same time each day. are available for indoor cultivation, although a standard also works. If your lights bring the temperature above about 80 degrees in your growing area, install a ventilation system to avoid heat stress. Aficionados use reflectors and all sorts of other grow light props to achieve optimal results.

How long should I leave grow lights on?

Plants grown indoors require more hours of light than those grown outdoors. 14-18 hours of light per day is recommended for most edible species when grown under artificial light. Don’t be tempted to leave the lights on 24/7 – at least six hours of darkness a day is essential for plant health.

As the plants grow, raise the fixture accordingly to maintain the optimum distance, which varies depending on the type of bulb used and its wattage (the higher the wattage, the farther the bulb can be). Here are the basic settings:

Fluorescent grow light: 3 to 12 inches

LED Grow Light: 12 to 24 inches

HID Grow Light: 24 to 60 inches

Happy planting!