Ultimate Guide To How To Choose The Ideal LED Grow Light Setup

Ultimate Guide To Selecting Proper LED Grow Light

When Considering Which LED Grow Lights To Buy, You Must Take Many Factors Into Consideration. First Consider The Grow Area, Type Of Plant, Budget, Understand and Define Your Goal, How Much Light Your Specific Plant Requires. Find Out More at eXtremeledgrowlights.com

By: eXtreme LED Grow Lights


So you are considering indoor gardening or maybe you are just considering upgrading your old HPS & MH Grow Lights to the latest energy efficient LED Grow Lights available at eXtreme Led Grow Lights today.

Regardless of the reasoning, follow this guide when selecting your grow lights and you can rest assured you will purchase compatible indoor grow materials that are compatible for the grow you target.

Consider the following factors when choosing the perfect LED Grow Light Setup:

  • Plant / Garden:
    • Demand of Light
    • On & Off Cycles or Phtotoperiod (ie. 12/12, 16/8, etc)
  • Area of you indoor grow:
    • Size
    • Shape
  • Understand and Define Your Goal:
    • Vegetative (VEG), Flowering (Bud) Or Full Cycle
    • Micro Grow or High Yield Grow
    • Active growth vs. maintenance

By selecting the ¹appropriate footprint coverage using light found on extreme led grow lights, you can rest assured that your goal Grow can be successfully achieved.

Grow Light Intensity and Duration

Grow Light Intensity Scale at ExtremeLEDGrowlights.com

Know your plants requirements as different plant types require different amounts of light for optimum growth. Keep in mind that plants require more light intensity during flowering stages (budding stage) than they do during the first phase which is the vegetative phase.

You can determine the total amount of light a plant has received in a day by both light intensity and the duration of the plant’s exposure to the light. This means that is a plant has had six hours of light per day, it would only take three hours for a light with twice the light intensity to create the same amount of light.

Make sense? Now we are going to get a little more technical, don’t worry though follow along and we promise you will be able to properly setup your indoor garden with proper LED Grow Light Selection. 

There is a DLI range for every plant that will optimize maximum growth and yield. Anything under this range will result in less than optimum growth and yield or even worse, no growth at all. Anything over the optimum DLI will be a total waste as it’ll cost more than it’ll make additional or could even be harmful or fatal to your plants. It is somewhat a task to determine the optimum DLI range and it depends on the

  • Plant Type
  • Growth Stage
  • Temperature
  • Humidity
  • Nutes
  • Oxygen
  • Light Spectrum

Confused? Well once again it gets more detailed as there are three categories in which you can divide plants into.

Short Day Plants– These plants flower when the night hours are greater than their critical period and without this change these plants will remain in the veg cycle.

Examples of Short Day Plants: 

  • Marijuana
  • Cotton

Long Day Plants– These plants flower when the night hours falls below their critical period.

Example of Long Day Plants

  •  spinach
  • radishes
  • lettuce
  • iris’s

Day Neutral Plants – Day neutral plants do not begin flowering due to a change in daytime or night time hours . They rely on some other stimulus such as reaching a particular size or age, or period of cold or drought.

Examples of Day Neutral Plants:

  • Auto-flowering or Auto-Budding Marijuana
  • peppers
  • tomatoes
  • cucumbers

Note: that some plants still require a dark period each day, even if they are day-neutral, short-day (vegetative stage), or long-day (flowering stage). For example, tomatoes grown under 24/7 light will get chlorotic leaves and grow poorly. Giving plants a 4-6 hour resting period each night is generally beneficial both to your crop and your wallet.

To the extent allowed by plants’ night-length constraints, you can increase the DLI by keeping the light on longer each day, without having to increase light intensity. For short-day plants like marijuana,  it is particularly necessary to have high light intensity during the flowering stage, as the DLI cannot be increased by extending the daylight hours.

LED Grow Light Intensity and Coverage

Each LED Grow Light uses LED’s to create light. The average light output per LED is the same as the number of Watts each LED in the grow light. Example; 3w led outputs 3w of light intensity. A 400W LED Grow light that has 5w led’s in it will have 80 led’s to make up the 400W LED Grow Light unit. Therefore it would produce 400w of light intensity. 

Ideally, you want to purchase a LED Grow light that evenly distributes the intensity over the entire footprint.

The intensity of the light within the footprint and the size of the footprint are controlled by how high you hand the LED Grow Light Unit above your plants.

If you were to move the light closer to the plant tops, it will decrease the size of the overall footprint but will increase the light intensity because you are spreading the same amount of light over a smaller area. So moving the light further increases the footprint but decreases the light intensity.

Make sense?

Regardless of the size light you are using, you can get an equivalent percentage increase in DLI by increasing the number of hours the light is on or by shrinking the footprint area.

example; increase DLI by 25% by shrinking the covered footprint by 25% or increasing the hours the light is on by 25%.

Getting simpler, right?

Indoor Garden Grow Aarea Shape

Most LED Grow lights incorporate a square footprint area, but you can still use them in a rectangular grow area. You have three options for covering a non square area:

  1. Use a light big enough to cover the longest dimension:
  • For a slight rectangular grow light coverage that can be the least expensive option. Use reflective material such as Mylar which is on most indoor gardening tents. Mylar helps the plants obtain the same amount of light. If your grow area longest side is more than 1.5x the length of the shortest side,  you should use the 2nd or 3rd option.

  2. Use multiple lights:
    • By hanging two or more lights side-by-side you can create a rectangular footprint. For example, two PhytoMAX 200‘s hung 2.5 feet apart (on center) will cover a 2.5 x 5 foot rectangular area, using our maximum recommended flowering footprint for photoperiod-sensitive Marijuana.
    • In a partial combination with option #1 above, these same two lights could also cover a 2.5 x 4 foot area, a 2 x 5 foot area, or even a 2 x 4 foot area.


  3. Use a light mover to “stretch” the footprint shape:
    • Hanging the light from a light mover will change the shape of the light’s effective footprint. The actual footprint is still square, but by moving this square footprint back and forth in a line, it is effectively transformed into a rectangle. Often the cost of an appropriate larger light with a light mover is less than the cost of two smaller lights without a light mover, making it the most economical choice for many rectangular growing areas.

Incorporate Light Movers To

Light Movers For Larger Grow Areas

Two reasons light movers are beneficial:

    • By moving a light back and forth in a line, light movers “stretch” the effective footprint of a light into a different shape, as long as you keep the effectively-covered footprint area the same.
    • For example, a PhytoMAX 800 can normally cover a 5 x 5 foot area (25 square feet) when it isn’t on a light mover, but moving it back and forth can make it cover a 4 x 6.25 foot area or a 3 x 8.3 foot area (both 25 square feet), although each setup requires a different light hanging height above the plants. When on a light mover, the light should ideally be hung at the appropriate height to get a square footprint as wide as the shortest side of the effective rectangular footprint area. For example, to cover a 4 x 6.25 foot area, the PhytoMAX 800 hung from the light mover should be hung at the appropriate height for a 4 x 4 foot footprint (24 inches above the average height of the canopy). This square footprint is moved by the light mover to create the rectangular effective footprint.
  1. Increasing light distribution to raise yield
    • When a light is hung overhead in a static (un-moving) manner, plants will naturally orient their leaves to catch as much light as possible. This often results in upper leaves shading out the lower leaves and flowers of the same plant. To some extent, this issue can be overcome by increasing the intensity of the light, but by simply moving the light back and forth and mimicking the sun’s natural daily traversal of the sky, light can be more evenly and efficiently delivered to all leaves on the plant. We’ve seen 10-20% increases in yield when a light is on a light mover covering the same size area, even when the light isn’t being moved very far.To some extent, hanging multiple un-moving lights provide many of the same benefits; having the light come from many angles helps to nourish more of the lower leaves. However, placing multiple-light setups on light movers will still increase light distribution and yield.

Considering how inexpensive light movers are to purchase initially, and how little electricity they take to run (typically less than 5W!), light movers are often the most economical way to squeeze extra yield out of a grow light.

Large Areas

Consider ease of plant access when setting up larger indoor grow areas. You should always be able to reach the plant to take care of it. You’ll also want to be able to access them when harvesting time rolls around. At eXtreme LED Grow Lights we like to recommend a maximum 3.5′ reach to access any plant in the grow area. An easy way to ensure this on larger grows is by incorporating aisles.

The perfect world scenario setup on a larger grow operation is to minimize aisle space while still allowing ease of access to each individual plant. If you have any questions about proper grow room setup, rather it be large or small, feel free to contact us at eXtreme Led Grow Light and ask us. Our manufacturers, as well as ourselves, combined add up to over 30 years experience in setting up indoor gardening grow rooms. We can surely help you solve your grow room questions.


Your Goals

Stages of Marijuana Growth extremeledgrowlights.com

The ideal LED grow light setup for your situation depends on what you want out of your grow, for example:

  1. Growth phase use: vegetative, flowering or both? If you want to use the growing area for only vegetative or flowering, you only need to consider the lighting intensity for that growth phase. When using the area for both phases of growth, it is best to design for the most light-demanding phase (usually flowering).
  2. Economize vs. maximizing yield: once the plants’ minimum lighting requirements (DLI) have been met, increasing the DLI will increase yield. Up to a point, increasing the DLI by a certain percentage will increase yield by a “linear” equivalent percentage; for example increasing the DLI by 10% may increase yield by 8%, and increasing DLI by 20% would increase yield by 16%. When you start giving the plants as much DLI as they can handle, this yield return on increased intensity starts to fall off and is no longer linear; for example if you’ve got a very high DLI to begin with, increasing it by 10% may only give a 4% increase in yield. Past a certain point increasing the DLI will not increase yield at all, and may even hurt it if the plants are being harmed by too much light.

The Ultimate LED Grow Light Area

Buy LED Grow Lights at ExtremeLedgrowlights.com

Here are some basic configurations to generally go by, based on budding day-sensitive marijuana plants. Four configurations are given for each :


  1. Minimum: At this DLI configuration, we’re sure you’ll be happy with the results; plants will grow and flower vigorously with dense, high-quality flowers. Yes, you can go below this a bit (increase footprint size and hanging height) and still get decent results, but they won’t be up to our standards.
  2. Medium: At this DLI configuration, we’re sure you’ll be thrilled with the results; quality may go up slightly and yield per square foot will go up.
  3. High: At this DLI configuration, you’re still going to see an increased yield per square foot roughly equivalent to the increased DLI, although by “overdriving” the plants with so much light you may need to pay a lot more attention to your plants to ensure they’re happy. Maintaining proper watering, fertilization, pruning and support becomes more critical as the DLI increases, so we would not recommend this level for beginning growers. Increasing DLI beyond this point will probably not result in a linear rise in yield, and the grams per watt yield will probably start to decrease, and costs go up.
  4. Extreme: At this DLI configuration, you’re probably maximizing yield per square foot, but in terms of yield per watt of electricity used (grams per watt) you’d probably be better off spreading the light out over a larger area or more plants. We would not generally recommend raising DLI above this point as it is most likely going to be wasteful, although every growing situation is different, and unique growing techniques may make use of all this light!



Grow Terms 


A lighting footprint, or light footprint, is the area that a particular light fixture is capable of illuminating. The term is more frequently used in indoor gardening situations where artificial lighting must be used.



Photosynthetic Active Radiation (PAR) designates the spectrum or range of colors of light from 400 to 700 nanometers that plants are able to use for photosynthesis. PAR measurements are usually expressed as photosynthetic photon flux density (PPFD) in units of μmol m-2s-1 — how many micromoles of photons (602,214,150,000,000,000 photons) within the PAR wavelengths of 400nm-700nm that go through 1-square-meter each second, though most devices that measure PAR do it only at a single point, rather than over a whole square meter. 


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