How to Calculate Grow Light Coverage

Straining your eyes? You can listen to this automated AI version of the article here:

Setting up a high-quality grow room for the development of healthy, well-producing plants can be time-consuming. Not only do you have to purchase a grow tent, pots, trays, and nutrients, but you also have to purchase grow lights. 

It’s easy to assume that you can pick any old lighting setup and have it function as it should, but that’s not always the case. You must ensure that the number of lights you purchase is suitable for the coverage area. To improve your chances of success while also speeding up the setting-up process, consider this helpful information below. 

Measure Your Plant Canopy – Not Your Grow Room

You might think that the best way to ensure you have enough grow lights for your growing setup is to measure your grow room and purchase lights designed to provide adequate illumination. In reality, your grow room size isn’t always an accurate reflection of the lights you’ll need. 

Rather than measuring your grow room, take measurements of your plant canopy footprint. For example, you might have a 4-foot by 4-foot grow room, but your plant canopy only takes up a three-foot by three-foot area. In this situation, purchasing grow lights for a 4x4 grow tent in NZ would be excessive. 

Surprisingly, you don’t have to be a mathematical genius to purchase adequate grow lights for your setup. There are only two steps for buying what you need: your plant canopy measurements and their lighting requirements of watts/square feet. 

What About Watts?

Working out watts can seem complicated, but just as you don’t have to be a mathematical genius to calculate your grow room space, you don’t have to be an energy expert to determine the wattage. 

In most situations, flowering plants grow at their best with approximately 20-30 watts per square foot. Performing this calculation can be crucial for avoiding providing your plants with too much light and heat. 

Plants harvest energy from the sun, with assistance from photon-capturing molecules like carotenoids and chlorophyll. If the plants are exposed to too much sun, the molecules absorb more energy than they’re capable of handling, generating a reactive oxygen species that can potentially destroy your prized plants. 

But what if you’re using LED grow lights?

Calculating your lighting coverage can be a little different if you’re using LED grow lights. Some manufacturers display two wattage specifications because LED grow lights are efficient. You’ll often see the display wattage, equivalent to HPS grow lights, and how this compares to the actual power draw of the LED lights. 

This would mean that if you had a growing space of five feet by five feet, requiring 320 to 480 watts, you’d want to ensure that your LED light kit featured an actual power draw/wattage of the same perimeters. 

How to Make Your Grow Light Coverage More Efficient

Power draw is a significant concern for many growers, especially with sky-rocketing power prices throughout NZ. However, there are ways you can make your light coverage more efficient to save money. 

Consider using multiple small grow lights rather than fewer large ones. You might also purchase wing-style reflectors, rather than a hood reflector, to spread the light efficiently and increase coverage. Some people also buy automated light movers as they believe these increase light coverage by up to 25 percent. 

What Are the General Coverage Guidelines for HPS Grow Lights?

If you’re purchasing HPS grow lights, you’re likely curious about the wattage you’ll need based on the plant canopy you’re working with. Here are some helpful guidelines. You can also contact our expert team if you need further assistance. 

Do I Need Grow Lights?

It’s the million-dollar question: Do I need grow lights? The answer is yes if you want to enjoy some of the following benefits. 

• Less energy usage than other lighting options – some sources report that grow lights use 17% less energy than other lighting types
• You can grow plants in any climate
• Full control over light coverage – ensuring your plants get the right amount of light and darkness to mimic the natural environment 

You also have a variety of different grow light options at your disposal, such as LED, HPS (high-pressure sodium), and MH (metal halide). Each of these options has pros and cons for you to weigh up. 

Ask the Experts for Help

You might be a plant expert, but that doesn’t mean you’re a growing light expert. If you need a helping hand choosing the best grow lights in NZ for your unique growing setup, don’t be afraid to reach out to Indoor Grow for help. We stock a wide range of LED, HPS, MH, and fluorescent light options to ensure you have the best of the best for optimal plant health.