Marijuana Lighting Guide Part I: Basics Of Lighting

While sunlight is always best for your marijuana plants, growing them indoors means you’ll need to buy marijuana growing lights.

You’ll have a lot of options from which to choose your marijuana grow lights. Beginning growers often find their menu of lighting choices bewildering. What’s more, your marijuana plants will develop more effectively using certain types of lights at various stages of growth. The good news is that most of the lights for growing marijuana aren’t expensive. In this guide, you’ll learn the basics behind each type of bulb you can buy. We’ll also explain what those bulbs do and offer a few tips for using them for maximum results.

Types Of Marijuana Lighting

The first choice you’ll need to make is deciding between fluorescent lights and High Intensity Discharge (HID) lights. Fluorescent lights aren’t nearly as powerful as HIDs; 20 40-watt fluorescents will put out less light than 2 400-watt HIDs. You can expect them to generate approximately 39 lumens per watt. You might want to consider using them when you’re first beginning, because they’re less expensive than HIDs. But, you’ll want to graduate to HIDs after gaining experience. Your marijuana plants will grow much better.

HIDs are available in 2 primary types: metal halide (MH) and high pressure sodium (HPS). Metal halide lights will last for 10,000 hours of use and can generate 125 lumens per watt. High pressure sodium lights will last about 18,000 hours and generate 140 lumens per watt. In Part II, we’ll explain which of these grow lights are best during the vegetative and flowering stages.

If you’re going to use fluorescent lighting, consider buying compact fluorescent lamps (CFLs). They use less power to generate the same amount of light as normal tubular fluorescent lights. You can also use incandescent lights, but only for the seedling stage and only if you’re growing 1 or 2 plants. They generate a much lower lumen output. We recommend that you invest in HIDs if you can afford them.

Marijuana Grow Light Tips

- If you have the budget, buy both metal halide and high pressure sodium lights. While each type of bulb is more effective at certain growth stages, using both simultaneously is even better.

- Use a 250-watt bulb if you only need to cover a grow area of 2.5 ft. by 2.5 ft. A 400-watt bulb will cover a 4 ft. by 4 ft. space and a 600-watt bulb should be used to cover up to a 5 ft. by 5 ft. space. If your grow area measures 6.5 ft by 6.5 ft., use a 1,000-watt HID.

- Be wary of the heat generated by HIDs. A 250-watt bulb should be kept 2 feet above the top of your plants. A 400-watt bulb should be kept 3.5 feet above their tops. Position a 600-watt bulb 5 feet above and a 1,000-watt bulb 6 feet above. Those distances will keep the heat from impacting your marijuana plants.