Gas-discharge lamps, such as classic fluorescents and high-intensity discharge (HID) lights, have helped indoor gardens thrive for decades. Fluorescents typically come in long, tube-like bulbs in various sizes. These are perfect for plants with low to medium light requirements, as well as seedlings and plants in their vegetative growth stage. Remember that narrower tubes produce stronger light, so a T5 is brighter than a T8. As the name implies, HID lights are more powerful than other lamps, so they’re ideal for all stages of plant growth. The arc tubes of HID lamps can vary drastically, but the most popular for indoor plant growth are metal-halide and high-pressure sodium-vapor lamps.

LED, which stands for light-emitting-diode, is currently the most widespread type of grow light. These bulbs are extremely efficient and produce very little heat in comparison to their brightness. They can fit a variety of lighting equipment and keep shining for years. Because of their customizability and brightness, LED lamps are great for any kind of plant at any growth stage. Ceramic metal halide (CMH) lights are essentially high-pressure sodium HIDs that can operate more efficiently thanks to their ceramic tubes. They are a wonderful choice for general growing, but they excel during the plants’ vegetative and flowering stages.

Once you understand what kind of lights you can choose from, you need to figure out what your needs are. Think about the size of your indoor garden or grow room. If you need to light up a massive area, the bright CMHs might be your best choice. You should also consider the plants’ needs. Every species prefers different light levels, so if your home is full of unique greenery, highly-customizable LEDs will be ideal. Ultimately, it all comes down to your budget. Don’t just think about the upfront cost, though. Costs can add up quickly when you need ongoing electricity, maintenance, and regular replacements.

If you look at photos of other indoor gardens, you’ll see that some plants are practically kissing the lights while others are lit from a distance. In general, the higher the bulb’s wattage and the narrower the beam, the further the lamp should be from your greenery. Ideally, you'll calculate your specific needs, but there are some general rules. Most LEDs should be between 12 and 18 inches away, while HIDs should be about two to five feet from the top of your plants. Fluorescent bulbs can be as close as five inches. Additionally, lamps should be closer to flowering plants and further away from leafy ones.

Once you understand how far your lamps should be from the plants, you can look into hanging and mounting options. Most importantly, you should be able to easily adjust the height of your lights as the plants grow. Most grow lights come with a set of hanging cables, hooks, and other mounting equipment. You can also utilize rope ratchets, chains, and eye bolts for your setup. The simplest process requires looping a single light through several eye bolts or hooks. More complex setups might involve a structure that houses multiple lights and requires additional support wires. If mounting to walls or ceilings is an issue, consider all-in-one stations, such as grow tents.

Lighting your plants all day wastes electricity and actively harms your greenery. While every species is different, most plants require between 12 and 18 hours of sunlight. Seedlings typically need more light, while fully-grown plants need less. If you wish to make the light cycle process easier, just utilize some simple timers. Some people like the more complex timers that include temperature shut-offs, while others prefer simple, clock-like timers like those you'd put on a lamp by the window when you're out of town.

Not all light is the same. Different intensities will affect your plants in various ways. You might not need to make adjustments to your lighting intensity if you never swap out your plants. However, if you like to change your plants around, you might consider a dimmable lighting system. LEDs are by far the most customizable, especially in terms of intensity. You can dim other bulbs—like fluorescents—but it requires a far more elaborate setup.

Additionally, don’t forget about the spectrum of light that your lamps produce. Most vegetation needs both UV light and infrared light, depending on the stage of growth. Plus, blue light might improve nutritional values in some plants, while others benefit from a higher red ratio. Choose the bulb that has the best spectrum of light for your needs. Again, LEDs are the most customizable, while CMH has some of the widest spectrums.

When you're running lamps for upwards of 18 hours a day, your energy consumption jumps dramatically. LED lights are the most naturally efficient, especially compared to fluorescents. CMH lamps are more efficient than other HIDs but still fall behind LEDs. In terms of changes you can make to your system, focusing your lights more allows you to use lower-power lights without losing effectiveness. Add reflective material to one or more sides of your garden to bounce light back to your plants.

Indoor gardens come with a few safety concerns that traditional gardens do not. Your plants need water, but you have many wires running through the area. Make sure to keep your wires safe and dry at all times. Additionally, do not attempt to crowd outlets, daisy chain extension cords, or splice together electrical equipment. Beyond that, some lights put out an extreme amount of heat that can damage the surrounding area or even start fires. Always keep fire safety equipment nearby and regularly inspect your system for wear and damage.