Over the past several years we have observed that the kind of indoor grow lights used to grow plants are constantly evolving. While a few years ago HPS lights were all the rage, growers are increasingly moving to LED grow lights - and even in LED grow lights there have been a number of changes in trends. Some people are quickly moving to fanless quantum boards from old-school LEDs while there are some who vouch for COB lights benign way better than SMD LEDs.

Why is Light Important for Growing Plants?

Plants need light for practically all their growth. Be it for the green leaves that you see on your plants or be it the flowers that come out of it. Even the growth of their branches and roots have a lot to do with the light that they get! The most basic function of light, however, is to help in the preparation of 'food' for the plants with the help of photosynthesis, where the light gets converted into energy which helps break down sugars for the plants. In addition to that, sunlight also carries lights of different wavelengths which have different functions such as improving root mass or improving the spacing of branches. Grow lights also help with the formation of chlorophyll which is very important for the plants to grow.

When your plants are growing outdoors, they have access to the natural sunlight which carries just the perfect lighting. However, when you grow indoors, you need an artificial source of light that can replicate the sunlight. This comes in the form of grow lights which are created in a way to provide your plants with the perfect indoor lighting experience. These lights combine full-spectrum lighting where you can ensure that all the required wavelengths of light are reaching your plants even when you grow them indoors.

There are a number of different types of grow lights available out there, but LED grow lights are the latest and the most popular ones. Here's a closer look at why LED lights are considered better than other forms of lighting.

SMD LED lights vs COB LED lights

SMD stands for Surface Mounted Devices, while COB stands for Chip On Board. In the case of an SMD grow light you will have chips that are fused onto a PCB (Printed Circuit Board). Interestingly, this is the technology that is used in the LED notification lights on smartphones, or on light strips, or on many similar platforms. SMD LED grow lights usually produce between 50 to 100 lumens per watt. The most common notion of "LED grow light" is an SMD grow light. An SMD system allows the growers to have three diodes per chip. Red, Blue, and Green diodes are put on these chips - when you adjust their output levels, you can mix them up to practically create any color!
With COB LED grow lights, the focus moves towards improving the efficiency of the energy. COB lights tend to have a much higher number of diodes per chip than compared SMD lights. While SMDs can have a maximum of three diodes per chip, COBs generally have a minimum of 9 diodes. Their circuit design too is much simpler when compared to the SMD lights which look quite complex and crowded. COB lighting also offers a much better lumen per watt ratio when you compare it against standard SMD lights offering a minimum of 80 lumens per watt on average. The most popular example of a COB light is in the flashbulbs of cameras.

King COB 360 Watt COB LED Grow Light

Features:
The King COB COB LED Grow Light offers a full, even spectrum of light. The limited wattage ensures the 360-watt professional series COB grow light from King COB will always stay cool, producing a full spectrum of light without the risk of heat damaging your plants. Unlike some other high-performance LED grow lights, the King COB professional series grow light uses just 360 watts of power. This increases the energy efficiency of the King COB professional series grow light, resulting in lower operating costs. It offers decreased heat generation and increased lumen output when compared with a traditional LED. The King COB 360 watt grow light has 6 moveable light bars which can be adjusted to provide the best level of coverage for your plant setup.
PowerInput: 85V-265V AC
LEDQuantity: 54x Ultra-Efficiency COB (Chip on Board) Diodes
ChipWattage: ~6w per diode
Spectrum: 3000K
PowerConsumption: 360W
LensAngle: 60°
Housing: Full Aluminum Housing
Dimension: 35in (L) x 23in (W) x 4in (H) (90x 60x 11cm)
Waterproof: IP65 (water resistant in humid, indoor growing environments - not waterproof [i.e. not to be submerged in water])

Optic 4 Gen4 Dimmable COB LED Grow Light 370W (UV/IR) 3000K & 5...

Features:
The LEDs in the Optic 4 fixture are equivalent to a 600-watt HPS bulb in terms of their output. Both the COBs and the supplemental diodes have the power to penetrate deep below the canopy. Secondary lenses focus the light even further and increase the PAR output by up to 200%. The recommended hanging height during flowering is 18–30 inches. During vegging, it is 30 to 36 inches. For seedlings, hang the light at 36 inches. This gives you a 3.3 by 3.3 coverage area during flowering and a 4 by 4 area during vegging. The COBs and the Samsung diodes deliver a full-spectrum white light that is great for all stages of growth, The CREE supplemental LEDs add red and blue to give plants even more of the wavelengths they need the most. They also add UV and IR wavelengths.
Actual Wattage: 370 watts
Input Voltage: 100v to 265v AC
Spectrum full spectrum plus IR and UV
PAR : 1035 umol/m2/s 
Coverage Area: Veg: 4 by 4 ft; Flower: 3.3 by 3.3
Operating Frequency: 50 Hz to 60 Hz
Thermal Management： 4 internal cooling fans; heat sinks
Dimensions： 18 by 18 by 4 inches
Product Weight： 24 lbs
Recommended Height Above Plants： 24 inches for flower; 24 to 36 for veg

Advantages of COB LED Grow Lights

Improved Electrical Efficiency
For grow lights, efficiency is measured in µmol/j or, more simply, the amount of photosynthetically active photons that are produced per watt consumed at the wall. This can also be interpreted as µmol per watt.
Improved Lifespan

High-quality LEDs have hands down the highest usable lifespan of any grow light technology available. Even if the initial investment is higher, a quality LED fixture will last AT LEAST 30,000 hours. So it'll pay itself off over time.
Based on manufacturer literature, double-ended HPS lamps have a life expectancy of 10,000 hours to 90% survival, or 1.65 years when used an average of 16 hours per day or 6,000 hours per year (traditional mogul-base lamps have industry-reported life expectancies of 10,000 to 17,000 hours, to 90% survival, and cost about $40).

The cost of a 1000W, double-ended replacement lamp is about $140, which averages to $28 per year if we assume a lamp will be replaced once in the first five years. Lamp replacement cost increases to $30 to $35 per year when the labor to replace the bulb is included, but this is small compared to the approximately $600 per year annual electric cost to operate the fixture. Adding the cost of lamp replacement increases the five-year cost of operation by about 5%.

By comparison, when operated at favorable temperatures, individual LEDs generally have a predicted lifetime (to 70% of the initial light output) of 50,000 hours, about 8.35 years when used an average 16 hours per day or 6000 hours per Year.​

Improved Light Quality

One of the main reasons that COB LED grow lights have made their way so quickly into many grow rooms is because of their HIGH Color Rendering Index (usually over 80) and broad-spectrum.

CRI stands for Color Rendering Index and describes how the color of a light source changes how an object appears to the human eyes and how well subtle variations in color shades are revealed. The higher the CRI, the more realistic things look.
This means no purple, or extreme orange, or red or yellow but high-quality white light showing realistic colors.​

Better Light Distribution

HIDs and COBs are both single-point light sources. But since COBs are comparatively easy to handle and position, we have a very different situation.

Instead of using one single light source, COB LEDs can be spaced for better uniformity in order to avoid hotspots or low-intensity areas in the grow room.

A practical example would be that instead of having one big 600W HID fixture that would create a hotspot, we could have 6 COB LEDs producing the same amount of light while consuming less and providing a way better spread.​

Superior Thermal Performance

This is a tricky one but bear with me. A 500-watt fixture will produce 500 watts of heat, period. Regardless of whether it is an HID, a CFL, or an LED. There's a common misunderstanding that 500 watts of LEDs are cooler than 500 watts of HID, and while that is usually true, it's not for the reasons people think.

The reason is mostly Infrared radiation. Far infrared is radiant heat, it's the same as the feeling of warmth from the sun on your face and the heat from a coal fire. It is even the same form of heat emitted by your own body. And LEDs (unless specifically designed to do so) produce very little infrared light, now compare that spectrum to an HPS and you'll soon understand why HPS lamps are always so hot.​

Conclusion

The COB LED Grow Lights are produced for commercial greenhouses, indoor grow facilities and research applications. Be sure about the purpose you need it for like the kind of plant cultivated and the photoperiod required. I wish you a happy planting experience.