To grow the biggest, strongest plants possible, you need to put together the ultimate grow light setup.

It may appear to be common sense that the better your grow lights, the better your plants will turn out.

However, it's not that as simple as finding the most expensive light and throwing it in your grow tent.

We first need to define what the "best grow light setup" is. Then, you need to understand what this means with respect to your growth in particular.

Basic Lighting Principle for Growing Weed

The idea is quite simple, really:
Hang a high-output, full-spectrum LED grow light or HPS grow light above the plants

Hang a lower-output, blue-spectrum light source to the side of the plants.

The plants get most of their light from the overhead HPS or LED light.

This is supplemented by the blue light source, either from an MH bulb or a cold (5500K and up) fluorescent bulb or LED equivalent (bar lights like these are excellent for this).
This secondary light source hangs about a third of the way down from the top of the canopy, in the rows between the plants.
The intense light from above feeds the plants and promotes fast growth and strong bud production.

But with only overhead light, especially the reddish light from an HPS bulb, plants tend to grow tall and thin.

This leads to poor production on the lower parts of the plant.
The supplemental blue light encourages thick growth on the lower parts and signals plants to increase bud production further down.

You get the best of both worlds with this grow light setup.
Red light promotes the production of buds and flowers and decreases maturation time, while blue light promotes more leaves, better bud quality, and tighter, sturdier growth.
Plus, with overhead-only lighting, the lower parts of the plants are usually looser and less lush than the canopy.
With this setup, the blue light is delivered to an area of the plants where it can have the biggest impact on yield and quality.

How To Optimally Place Your Grow Lights

How Grow Lamps Function
Except for the top and bottom of the arc tubes where obstructions are located, the construction of grow lamps enables light to go in every direction. Artificial light production is brought about via agitation of the chemicals, which occurs in a high-voltage vacuum tube. The glowing of these chemicals allows light to come from its source at 360 degrees.

This obstruction blocks light, meaning that just half the light is coming out at the end as compared to six inches to the side. This is determined with a light meter. This is caused by particles that are near the glass arc tube at the time of agitation.

Reflecting Light Correctly
The reflection of light is very important for creating an ideal environment for your plants to grow. Therefore, the location of the wall that creates this reflection is also of great importance. A reflective wall is necessary for capturing the growing area's light when your room space is bigger than your growing space - otherwise, you would need to light up the rest of the room as well as the walkways. This is clearly a waste of electricity. You can use Myler or other silver, shiny products for your reflective wall, but a reflective white paint is favored by most professionals. Make sure to downoad my free grow bible at this link and grow like a pro!

For ebb-and-flow gardens, it's important to set up your reflective walls just 6 inches away. Because the width of ebb-and-flow tables is usually four feet, putting up reflective walls at this distance still allows for airflow, as well as the bushing out of your plants. You'll need to set up your reflective walls a bit differently if you would like to grow plants that are bigger. Do it at five-foot centers per 1000 watts. For example, use a single light if it's 5×5 feet, 10×5 feet should have 2 lights, 15×5 feet should have three, 10×10 should have four, etc.

The air-cooling of such lights allows for hot air's removal, taking it away from the growing area. At the same time, a loss of light is avoided because of the reflective, white-colored walls.

Maintaining the Efficiency of Your Lighting
You should make sure there's an equal cover of light across your entire garden to properly set up your lights. You can use a light meter to ensure that no hidden hot spots exist.
Another easy way to test the intensity of your lights is simply through feeling with your hands. Leave your bare hands where you plan on placing your plants. If you're unable to keep your hands there for long due to the excess heat, it's a good indication that your plants also would be uncomfortable with such lighting. To put it simply, as a rule: Whenever you're uncomfortable in the grow area, so are your plants. This includes temperature, humidity, ventilation, and so on. If you don't correct this, you will definitely have a smaller yield.
One important fact to note is that some light (10%) can easily be lost simply by choosing to burn your lamps horizontally. The lamp also can lose 25% of its lifespan, meaning that to achieve the highest light output, lots of growers will simply change the light after just 75% of one year's usage.

For horizontally placed lamps, two-thirds of the lamp's light emissions bounce off the reflector, while just one-third goes straight to the plant canopy. Losing light because of the quality of the reflector's material can also occur; if it's 92% reflective, you're losing even more light - 8% in addition to the two-thirds already lost. Reflectors with built-in glass lose a further 3–5% of light.

For more specific numbers: 100 watts would be lost per 1000 watts (10% loss), and 666.66 watts of light (two-thirds of 1000 watts) are being affected. Therefore, losing 8% and then another 3% means an 11% loss of 666.66, which is 73.33 watts. Adding the original 100 watts to that means that, in total, 173.33 watts of light are being wasted. In other words, nearly one-fifth of the yield is ruined simply because of the orientation of your lamps.

Wave cancellation is another factor that can cause light loss due to horizontal lighting. Wave cancellation causes the loss of light when it is bounced back at itself. It can be confusing because the light seems to be continuous, given the fact that its bandwidth is extremely small (only nanometers), and its creation is at time intervals invisible to the naked idea.
Although we know that there is a clear light loss when it is redirected into itself, we do not know exactly how much this is. Another factor is the elements used in lamps, where their agitation from electricity (especially salts) occurs. Simply put, expensive artificial light should not be wasted. This gives a high value to light meters, as well as the optimal positional of lamps.

How Much Light Does Your Grow Room Need?

To establish the correct amount of light for your crop, you need to multiply your grow room length by its width to obtain the growing surface, then multiply the obtained figure with your desired PPFD level.

If your grow box is 250cm long and 80cm wide, your grow space will be 2.50m × 0.80m = 2m². If you aim for a flowering plant canopy of around 2 square meters and you want to experiment with a PPFD level of 500μmol, you simply need 1,000μmol/m²/s. This result should then be divided by the PPFD per watt of light to ascertain the wattage needed.

Conclusion
If you're thinking about starting an indoor garden this year, you need to get the best advice possible.

You'll find plenty of experienced growers willing to give you some advice. Get recommendations on the best equipment brands and avoid making the same mistake novice gardeners make in their first season.

There are dozens of grow lights out there to choose from. However, only a select few provide the best grow light for your garden. Make sure you select a device that suits your gardening needs and your budget.