Total Spectrum Control LED Grow Lights + UV-B for Your Marijuana Plants

Early last year I got a California LightWorks 1100 LED grow light, along with an optional controller unit, and an optional set of UV-B T-5 fixtures that attach to the main grow light unit on each side. All this gear is manufactured by California Lightworks (CLW), one of the top LED grow lights manufacturers based in North America.

This gear acquisition was part of my decades-long project to find the best grow lights for cannabis. My project has so far tested nearly two dozen HID (high intensity discharge), LED, and plasma grow lights. I do individual testing and side-by-side comparison testing using uniform clones and other controls to ensure grow light effects are the only variables being measured.

I only have a couple of premium LED brands left on my grow light testing bucket list, including the highly-lauded Fluence LED line-up. Of all the grow lights I’ve tested so far, the California Lightworks 1100 LED ranks in the top three. In some categories, it’s the best grow light I’ve tested.

Note that the CLW 1100 is part of a series of lights the manufacturer offers, called the Solar System series, which includes smaller, lower-power lights targeted for grow phase, propagation, bloom phase, or small spaces. This company astutely recognizes the needs of growers in various situations–from grow tent to large commercial space–and makes top-rank LED grow lights to match.

My favorable view of CLW grow lights isn’t just based on the impressive performance testing with my cannabis plants. It’s also because California Lightworks uses high-end design, engineering, electronics and materials.

The company describes the CLW 1100 as the most powerful grow light in their product line, a start-to-finish powerhouse that equals or beats the yield, growth rate and performance of 1000 watts of single-ended HID lighting with far less electricity draw.

It runs very cool, the coolest of any comparable wattage grow light I tested. Even when the light is at maximum output, it only draws 800 watts. The CLW 1100 has a casing and body made from aluminum, which is probably the most efficient heat sink material grow light companies can use. The company’s engineers told me their heat sinks are much larger and more effective than in other grow light brands, and that they use way more high-quality aluminum than most grow lights manufacturers use. The unit only weighs 26 pounds, which is light enough for most light stands and light movers.

Heat sink effectiveness leads to cooler operation and longer unit life, as there’s less heat to degrade components and LEDs. California LightWorks guarantees at least 40,000 hours of operation with little or no drop-off in light quality or output. I’ve spoken to commercial growers who’ve run their California Lightworks lights almost continuously for tens of thousands of hours with zero failures of any kind. This reassuring reliability and longevity are reasons that well-made LED grow lights are a much better investment than HID grow lights. Using HID, you have to replace your bulbs every crop cycle or two. Over time, using HID costs a lot more than using LED.

California Lightworks uses 5-watt Osram diodes; industry experts put Osram above all other premium diode makers (Cree and Philips) in terms of efficiency and light output, and 5-watt Osrams are said to put out twice as much light as 3-watt chips with half the heat and electricity waste. California Lightworks was founded by and is owned by engineers; the founders’ engineering background is shown in their products’ superlative design features, such as specialized circuit boards and other electrical and structural strategies that minimize heat and optimize performance and longevity.

One of the nuances about LED grow lights that impact how useful the lights are involves the angle of the light dispersal physics, and whether the manufacturers have placed lenses or other materials to interface between LEDs and plants. The angle that LED clusters are set into their frame makes a difference in coverage.

Some manufacturers put magnifiers or directional lenses on diodes to narrow, focus and concentrate the angle and/or intensity of light. This greatly impacts coverage area and usefulness, with some units so narrowly focused or intensified that they have to be elevated very high above plants to avoid leaf burn. Some units have a dispersal area that’s too narrow, others are too wide, or there are hot spots and dark spots caused by how the diodes are arranged in the unit. In the active area that this light covers, illumination is perfectly even, with ample blending of the three color bands to create an attractive bluish-white tone.

So the CLW 1100 doesn’t have any magnifiers or other apparatus on its diodes, and its footprint is mildly rectangular, with uniform dispersal. The unit is approximately 18 x 18 x 4 inches by itself. When you’ve added the optional T-5 UV-B fixtures that attach to either side of the main unit like wings, the total size is approximately 23 x 23 x 4 inches. The unit has cooling fans on top, rather than passive cooling, but the fans are the quietest I’ve ever heard from an LED grow light.

Speaking generically, because every grow room and set of plants is different, the CLW 1100 coverage area for grow phase is 17-23 square feet, and for bloom phase it’s 13-17 square feet.

Why such a broad and approximate range for coverage areas? Because the CLW 1100 used with its controller gives you the ability to incrementally and independently adjust intensity and ratio of all three color bands (red, blue and white), starting at zero and going up to full power, which is denoted on the controller as 99. The fact that you can vary the light’s intensity impacts how high you can place the light above your plants and how much radiation is generated by the light. These affect coverage area.

I can assure you that in the coverage area under the California Lightworks 1100, all plants receive even, mixed spectrum lighting at optimal intensity levels. Light distribution is incredibly even and uniform. This isn’t the case for most grow lights.

Customizing Light Wavelengths for Cannabis Plants

The ability to infinitely adjust color band intensity and ratios is for me the most useful but not the only superior, proprietary feature that puts the CLW 1100 near the top of the ratings charts for grow lights.

To understand why using the CLW controller to micro-manage your color bands is so useful, know first that radiation delivered by grow lights can go from ultraviolet all the way to far infrared, with the normal visible spectrum in between. Many grow light companies talk about photosynthetically active radiation (PAR). Of course PAR is important, but grow lights such as the CLW 1100 generate radiation that beneficially affects plant growth rate, health, and yield, separate from just stimulating photosynthesis.

HID grow lights are especially primitive when it comes grower control over the range, intensity, ratio and targeting of radiation wavelengths. With HID, you’re limited to using metal halide or high pressure sodium bulbs, or offshoots of them such as ceramic metal halide. HID bulbs come with a preset range of wavelengths the grower can’t alter. In my research, I’ve found no HID bulbs accurately engineered to provide a spectrum ideal for cannabis. Most of them have big spikes in red, orange, and middle-blue spectral output. This old school approach wastes electricity and doesn’t maximize plant potential.

Indeed, HID’s lack of grower radiation control cripples your ability to precisely use light as plant nutrition. Plants “eat light” through their leaves, as they eat mineral elements through their roots. Mineral elements affect plant growth, metabolism, floral structures, and production of cannabinoids and terpenoids; that’s why there are two different base nutrients categories for cannabis: one for grow phase, one for bloom. That’s why there are phosphorus and potassium boosters for flowering phase, but not for grow phase.

Too much fertilizer nitrogen at the wrong time creates tall, gangly plants. Too much red/orange grow light spectrum does too.  High pressure sodium grow bulbs commonly used in bloom phase are predominantly red and orange in their wavelength spectrum. Metal halide bulbs used in grow phase are predominantly blue. They both often deliver wavelength ratios that run counter to what promotes your high-yielding, high-potency bud goals.

I hoped to see some science to back up the specific spectrum choices designed into HID bulbs, but when I asked the leading HID grow bulbs manufacturers to show me research proving their light spectrums optimize cannabis growth rate and structural integrity in grow phase, and optimize budding and resin production in bloom phase, they admitted they don’t have any research to show me.

My years of personal photobiology research indicates that almost all HID grow bulbs have too much red and orange and not enough blue. The red-orange part of the visible light spectrum is important for cannabis, but I’m convinced that bloom phase stretch is partially a consequence of overly red/orange HPS (high pressure sodium) HID bulbs delivering the red-orange wavelengths that promote long internodes. More blue, less red, is what is needed. But despite their spectral deficiencies, HID grow lights might still give you large, gooey harvests because they overdeliver on intensity. HID effectiveness comes because a massive dose of photons is thrown at the plants. This overdose comes at a high cost: massive electricity consumption, waste, air conditioning and venting to get rid of HID heat.

Only with total spectrum control like you get with the CLW 1100 can you have mastery over light wavelengths in a way that shortens crop time while increasing yield and potency per watt.

Premium LED grow lights generate way less heat and are more energy-efficient than HID grow lights, but many LED grow light brands mimic HPS, so they have a pink, red, or orange tint to their light output, and unlike the CLW 1100, they don’t have a controller that allows you to customize light wavelengths. They’re not optimized to deliver the exact radiation spectrum that best drives your plants to give you their heaviest harvests and the most trichomes per watt. Many brands of LED grow lights are great for grow phase, but not adequate for bloom phase. Fortunately, the California LightWorks 1100 doesn’t have that problem. It can be expertly customized to deliver ideal light wavelengths for grow and bloom.

The CLW 1100 is $200-400 less expensive than units from other manufacturers that are in the same prosumer class. The company offers a solid 5-year warranty. I’m very impressed by their technical support staff, who were crucial in helping me as I experimented with the controller to set a wide variety of spectral outputs.

The company provides generic guidance about light intensity settings for red, white, and blue, broken down by plant life phase (seedling, veg, pre-flower, peak bloom, finishing). They have presets built into their controller too. They provide guidance about using their optional UV-B fluorescent lights, and using the controller. I’m a low-tech guy, so I only use the most basic controller functions, but the controller has a vast array of highly useful options and settings. Its programmability is truly astounding.  Also, if you’re running more than one CLW grow light, you can daisy chain the lights and use one controller for all of them.

My main use of the controller is to incrementally adjust white, blue and red diode channels. This brings me back to the company’s recommended light dosage recipe for various stages of crop growth. My experience with this grow light and its recommended wavelength recipes is the same as with using hydroponics nutrients: the manufacturer’s recommended dose may or may not be perfect for your plants in your grow room.

Lots of factors affect how much and what spectral mix of radiation should be delivered to your specific plants at different stages of growth. Marijuana genetics, whether plants are seedlings, clones, or older, the type of growing system (deep water culture versus soilless mix, for example), how well the grow room is climate-controlled, vented, and humidity-controlled, vertical grow room space, and other factors make generic light dosage recommendations only a starting point. Using the CLW recommended dosage for seedlings and clones, for example, I overlit the seedlings and clones, driving their morphology downward and horizontal because there was too much light for them.

Please note that the CLW 1100 is so efficient and powerful that it’s easy to burn or overlight your plants unless you properly set intensity and height. My experiments showed I needed to use the light 40-48 inches above clones and seedlings until they’d developed strong, robust root systems and 3-5 sets of true leaves. Not only did I have the lights so high above the plants, I also scaled back intensity to about 65% of CLW’s recommended dose.

During grow phase, I continued my scaled-back intensity, and kept the light rather high above the canopy. The good news is that because I have adjustable light hangers and the CLW controller, I’m able to micro-adjust grow light height and spectral output many times per day if I want to. Do your own controlled experiments, in consultation with the manufacturer’s tech support staff, but err on the side of caution because these lights are very efficient and potent.

The adjustments I make to my grow light height and spectral output are partially based on observing the condition of my marijuana plants’ leaves. If leaves are burning, bleaching or showing other signs of light/heat stress, it’s obvious I have to reduce intensity, raise the lights, or both.

It’s easy to burn and bleach leaves using professional LEDs. Why? Because the lights run cool, you can stand under them and not feel the searing heat and burn warning easily detected if you get too close to an HID bulb, and because some LED grow lights are delivering targeted radiation that leaves aren’t used to receiving, especially in an indoor grow op.  The symptoms of LED leaf burn are hard to detect at first, and often mimic the look of nutrients problems.

I like to see healthy leaves that are “praying,” which means that they’re elevated slightly upwards rather than hanging down or parallel to the ground. When I see leaves arching towards the light rather than away from it, but not in a way that indicates they’re experiencing a light intensity deficit, I’m happy.

The point I’m making is an advanced grow light system such as the CLW 1100 and its controller isn’t a simplistic, amateur-level plug and play system.  Serious growers know you always have to closely observe coverage area and plant effects with any grow light. When you love marijuana growing and are a perfectionist about maximizing crop inputs including light, this awesome unit is a powerful tool you use to craft the exact radiation spectrum for your set of cannabis plants.

You could use the generic light intensity and ratio guide recipe provided by California Lightworks for each phase of growth, but to get the full benefits of this amazing LED grow light, it’s best to do personalized experiments. For example, I found research showing that standard dosages of red/orange spectrum provided by most LED and HID grow lights create negative crop outcomes such as long internodes, so I deviated down from the manufacturer’s recommended red channel dosage, increased blue and white, and shrunk my internodes and bloom phase stretch.

A diligent grower will pay close attention to distance of grow lights from plant canopy, and make adjustments whenever needed. Plants get taller; their light requirements change. With the CLW controller, I micro-adjust intensity and spectrum. With my light hangers I micro-adjust height. Height, intensity, and spectrum determine how well my grow lights and marijuana plants work together. Using the CLW 1100 properly set and placed, I increase growth rate, crops are ready for flowering faster, buds develop and mature faster, and harvest comes sooner. This translates into more crop cycles per year, which means more buds, more profits.

By the end of grow phase, the grow light was at least a foot closer to the plants than at the beginning–about 26 inches from my canopy or a little higher than that. Penetration was sufficient, especially because my blue-dominant handcrafted spectrum creates shorter, stockier plants that have more bud and less stalk and stem.

I activate side-mounted CLW UV-B fixtures for the last three light cycle hours of each day during peak bloom and late bloom. UV-B is generally accepted as a radiation stimulant for resin production. Research shows that marijuana plants given added UV-B just before a dark cycle build more cannabinoids and terpenoids than plants given added UV-B followed by continuing illumination. CLW UV-B lights draw virtually no electricity. I’m planning to test the effects of running UV-B for a few hours during the lights-off cycle, after hearing from a research scientist that this too increases cannabinoid and terpenoid production.

Comparative yields testing is difficult in real-life grow situations unless you do grow tents or isolated grow rooms using identical clones with identical inputs and environment. In those kinds of tests versus other LED brands and the top HID brands, the CLW 1100 consistently gives me close to a gram per watt if not more. The buds are stickier, denser, with more resin glands and less leaf, stalk and stem, compared to buds grown under HID, including double-ended.

Given that its total operating costs are 30-50% less than operating HID lights, its harvest weight outcomes are comparable or minimally lower than HID, and the cannabinoid and terpenoid percentages are higher, the CLW 1100 system is for sure a worthwhile replacement for 1000-watt HID lights.

The CLW 1100 would be overkill in a grow tent or any grow space with limited vertical height. There are other lights in the CLW line-up that work better in those situations. For professional or commercial production using full-size photoperiod marijuana plants or photon-hungry sea of green, the California Lightworks 1100 is an ideal choice. The ability to tailor its output so you give your plants exactly the spectrum mix they need is a great way to curtail electricity costs and exploit how cannabis responds to different intensities and wavelengths of light energy.

Because I’m the kind of person who wants total control over every aspect of my cannabis plants’ performance, the CLW 1100 and its controller are the perfect technology for me. No other grow light option, especially HID, offers you such precision control over the radiation you feed your plants.

As with any professional LED, these lights cost more than a 1000-watt HID reflector, bulb, and ballast. But they last a minimum of 40,000 hours, they’re cooler and quieter, and the savings you get in wattage consumption and reduced air conditioning costs pay for the lights within a few crop cycles. These grow lights are elegant, state of the art cannabis cultivation tech, and they’re fun to own and operate.

Contact the good people at California Lightworks and ask them to explain how their proprietary, USA-made, premium technology can improve your grow op. These impressive marijuana grow lights are also available for European growers via LED by Passion. Check them out today!

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