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How to Increase Cannabis DLI for Bigger Yields

DLI for cannabis

What is DLI for cannabis? Below, we will find out by looking at all aspects of cannabis DLI. Plants need light units for photosynthesis, described as DLI (daily light integral). DLI affects the yields, and learning how to optimize it improves your harvest’s quality and quantity.

Increasing DLI for more and quality yield

Picking superior genetics for your grow is a no-brainer. Proper preparation from the soil, aeration, water supply, fertilizers, to lighting follows. Nonetheless, many first-time growers invest more energy and time following the plants’ growth and monitoring the changes per stage while paying little or no attention to light, one of the essential nutrients.

Plants require DLI, described as photosynthetic active radiation (PAR) per area in a day. PAR is the light wavelength range supporting a plant’s photosynthesis, measured in nanometers ranging from 400 to 700 nm. Your cannabis plants require 35 to 50 DLI units for healthy growth. Determining the optimum DLI considers several aspects, including light intensity, source, lumen spread, and hours.

Increasing DLI improves photosynthesis, resulting in higher yields. Nonetheless, your plants won’t automatically produce bigger buds just because you placed the grow lights closer and cranked them all the way up. Too much can even harm the yield. The trick is to understand how DLI is measured and how to increase it accordingly for optimum plant health.

Measuring and optimizing DLI

The two essential terms you must know to help you accurately measure DLI are micromole and PPFD (photosynthetic photon flux density). Micromole is the unit measurement of PPFD. It measures the unit reading over a square meter each second. PPFD is the plants’ light intensity, measured in micromoles per square meter per second. DLI is the PPFD per day, measured in moles/square meter/day. PPFD drops with an increase in distance. It means the further your grow lights are, the lower the PPFD.

Don’t scratch your head so hard. If math is not your cup of tea, invest in PAR light meter, also known as a quantum PAR sensor or PPFD meter. It takes the heavy lighting out of the equation, allowing you to know and adjust the DLI for bigger yields.

You know how to calculate DLI, but how do you optimize it? Cannabis needs light throughout its cultivation stages. Nonetheless, what works during infancy is not the best for vegetation and flowering. Knowing the DLI best matches a certain stage lets you streamline and optimize grow for maximum yields. Here is a glance at the various stages and recommended DLI.

Cannabis DLI for flowering stage
DLI for cannabis in the flowering stage.
  • First weeks: The first three to four weeks determines how strong your plants get as they grow to cross to the vegetative stage. 15-19 DLI units, this is, 200-300 PPFD for 18 hours is ideal.
  • Vegetative stage of cannabis: This is the most demanding stage, not just considering DLI. You are at odds on many fronts since it is the make-or-break phase. Twenty moles is ideal, but following your cannabis strain and plant size, you can increase. Most cannabis takes upwards of 35 units during the vegetative stage. The plants demand more energy, making it critical to increase the DLI without overlooking concerns like the potential heat, ensuring they hit maximum growth potential.
  • Flowering: The flowering cannabis stage determines the yield to expect. You want the optimal lighting to ensure they flower as they should. The DLI at this phase averages 40 to 60 units per day.

How to increase DLI

Improving DLI is easier than you expect. Among the top measures include:

Eliminate obstructions

If you didn’t consider it, especially when growing outdoors, obstructions need to be removed. They affect plants’ exposure to sun rays. Clear the space, allowing the plants to get the sun’s full gifts, but be careful if the area receives extremely hot days or growing in-house. The fewer the obstructions, the better the lighting, increasing your canna yields.


You’ve established the sun isn’t getting to your crops as much as you desire; how do you improve the lighting? Installing grow lights around the plants is the straightforward answer. However, when illuminating the area, ensure optimal light positioning to avoid excessive heat, especially with those cheaper options. Improving aeration helps keep the heat accumulation at a minimum.

Stronger grow lights

When growing indoors, you solely rely on the grow lights. Here, you must consider the PPFD concentration to ensure optimal DLI. Follow the general rule; go bigger or go home. Buying cheaper lights only limits the light quality. Invest more dollars; the high and quality yields are worth it. The best LED grow lights feature innovative measures. You get to adjust the lighting per phase, ensuring the plants get the right intensity and exposure per day for healthy growth.

More time

How long do you leave the lights on? Keeping the lights on for a longer period increases DLI. The more hours the plants get the right per day, the higher the DLI. Nonetheless, the debate on whether 12, 18, or 24 hours is the best is flexible. This mostly relies on the strain, environment, and phase. For instance, leaving the lights on 24 hours is ideal if the growing area is cold, keeping the space warmer. It helps if you place the lights further from the plants if you feel the DLI is too high.

Increasing DLI improves the yield, but it is not as simple. You still need to ensure the plants are in a good environment, well-nourished, and healthy. Increasing the DLI when the plant is unhealthy only worsens the situation. When in the right setting and with proper nutrients, the increased DLI translates to a rise in photosynthesis, hence a more significant yield. Moreover, increasing DLI beyond what the plants can handle risks harming them. Higher intensity than your cannabis plants can take also gets them maxed out faster, meaning more of your effort goes to waste.

Light plays a critical role in plant growth. The right DLI means bountiful yields, whether grown indoors or outdoors. The plants need photons for growth, and while the limits are negotiable, you need to be keen to ensure optimal lighting. Overdoing it, while less likely, especially with the best LED grow lights, is possible. Be on the lookout for signs like yellow leaf tips or light burns.

Picture of Taylor Christianson

Taylor Christianson

Taylor is an indoor expert. Through their writing, they offer a masterclass on growing cannabis indoors, maintaining a productive growing environment, and guiding growers through all the stages of growth both indoors and outdoors. Combining multiple fields of expertise allows for Taylor to give in-depth insights into overall cannabis growing. About this Author

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