0 item(s) - $0.00
You have no items in your shopping cart.

Maximizing yield with LED grow lights

Gardening with LED Grow Lights rather than HPS or other outdated technology is proving to be one of the biggest advancements for indoor gardening in decades. Growing plants with LEDs is becoming increasingly common, but practical ways to get the best results when using this new technology are still being discovered and shared. Swapping out old HPS setups with LEDs is easy and, watt-for-watt, will out grow any other lighting technology such as HPS. Gardeners will find that very little changes from their usual plant care regimen when moving to LED for their indoor garden, but there are a few best practices and simple tips that will allow you to get the most out of your garden with Black Dog LED.

1: Use the Right Light for Your Situation

This is your "sunshine in a bottle". Without sunlight, almost all life on earth would go extinct. Without using an optimum LED grow light, you will waste energy and your garden will suffer. Spectrum, intensity, and coverage are fundamental factors when deciding on which light to use. Select an light powerful enough to provide light for the space and plants it will grow. Black Dog PhytoMAX LED grow lights come in 5 different sizes to best suit your space and light requirements; see our guide to the perfect led grow light setup to determine what is best for your situation.

2: Spectrum

The spectrum of an LED grow light is arguably the most important factor when it comes to how well your plants grow. Plants require certain wavelengths of light to live and thrive; each colored LED emits light in a fairly narrow wavelength so many must be combined in the proper proportion, intensity, and pattern before it will grow a plant. Therefore, using a light with a complete spectrum is critical. Most LED grow lights rely on a light spectrum adequate to keep plants living, but lack spectra outside this bare minimum. Premium LED grow lights such as Black Dog LEDs integrate additional wavelengths to their spectrum allowing plants to flourish, from seed to harvest. No other LED indoor grow light company uses as many distinct wavelengths of LEDs to create the perfect mixture of light generating a truly complete spectrum.

3: Temperature

When using LED grow lights for indoor plants, the growing area needs to be kept warmer than if you were using other grow lights. In general, the air in your room should be 83-85 °F when the lights are on (daytime). In a standard HID light setup, 75-76 °F is typical when not supplementing with CO2.

4: Fabric / Cloth Pots

In non-hydroponic grows, many gardeners are now using fabric or cloth pots instead of plastic pots. Fabric pots have the advantage of being able to let your roots "breathe" and air-prune, encouraging roots to spread and develop a favorable "fish bone" structure. While these advantages are well known, we have found them especially beneficial in LED gardens. In a standard HPS setup, the undesirable infrared heat evaporates water from your soil, however quality LED grow lights do not emit this heat, so having pots that "breathe" allows for more regular feeding and reduces the chances of overwatering. If you are still growing in old plastic pots, switching to fabric can boost growth and yield. You can see more details and purchase original SmartPots here.

5: Reflective Surroundings

Surrounding your grow area with reflective materials helps to get more light to your plants and distribute it more evenly, so that leaves or plants on the outer edge of the lighting footprint grow more like the ones in the center.

Reflective materials aren't a strict necessity but they are one of the cheapest, easiest ways to boost your yield.

What we think of as being the best reflective surfaces (mirrors and mylar) aren't actually reflecting as much light as you'd think; we see reflected images in these surfaces because the surface is "throwing away" light that isn't bouncing back at the right angle to form an image. Flat (not glossy) white surfaces reflect almost all of the light that hits them, regardless of the angle it comes from. Orca film is the best reflective material for growing, followed by flat white paint, then Panda film and finally mylar. While Orca film is a little more expensive up-front, it is much sturdier and easier to clean than any of the other options, and lasts many years longer than any other reflective material we've ever tried. It is also light-tight if you're trying to make sure your garden doesn't have any light leaks.

6: Light Movers

Moving an LED grow light even a few inches back and forth above your garden allows light to reach parts of the plant that would normally be shaded if the light was stationary. While this is true for other indoor grow lights, due to ducting, reflector size, and heat, light movers have become harder to implement in many standard HID gardens. Using Black Dog LEDs, you do not have these issues, making them easy to hang and move. We offer heavy-duty Light Rail 3.5 light movers here.

7: Nutrients / pH

Use nutrients designed for your garden. Make sure the nutrients you use are intended for your type of garden. Nutrients rich in organic materials would not work well in an aeroponic garden, and nutrients designed specifically for hydroponics could cause problems in an all-organic garden. Nutrients should be applied at the recommended strength, changed out regularly in reservoirs, and adjusted according to the stage of the plant's life (veg/flowering). Properly adjusting and monitoring the pH of water and nutrient mix is another key to success. For most plants, a pH around 6 is good, although there are exceptions. Plants cannot uptake nutrients if the pH is too high or low. You can read more about pH here, including the 3 key steps to properly adjusting pH in your water and nutrients.

8: No Pathogens

Keeping pests and disease at bay is essential in a successful garden. Pathogens can infiltrate a garden by arriving on cuttings or other plant material from outside sources, such as trading clones ("sleeping around") or hitchhiking on clothing, skin/hair, and especially shoes. Washing your hands, changing clothes/shoes, and sterilizing equipment are important practices. A clean garden is a happy garden. When using grow lights, wearing specialized LED Grow Glasses will help you to find any issues early, before they get out of hand.

9: Consistency

Maintaining consistency in you garden is vital. Changing the light, temperature, nutrients, or any other variable will have an effect on your garden, good or bad. Without consistency, if a problem (or advantage) does develop, figuring out what caused it can be impossible. Another aspect of inconsistency many gardens have suffered from is what we like to call "Mad Scientist Syndrome" and while I'm sure we are all guilty of this at some point, just because you have a bottle of something that says it's good for plants doesn't mean you need to use it. Especially for those just getting into indoor gardening, selecting a nutrient program and following the manufacturer's schedule is highly recommended.

10: CO2 and Air Movement

When all other aspects of your grow are dialed in, yields are consistent, and environmental conditions are tuned, the addition of supplemental CO2 can make a big difference in growth and yield. Carbon is responsible for the majority of weight in dried plant material, and is only taken in by the plant through the air/atmosphere. Supplementary carbon dioxide can be supplied by a variety of sources including CO2 tank and regulator setups, CO2 generators/burners, and to some degree CO2 "bags" and "pads". A concentration of 1350-1500 ppm CO2 is ideal for most plants. CO2 should only be added when the lights are on (daytime), never at "night", and should be discontinued 7-14 days before harvest.

11: Growing Styles and Techniques

Manipulating the structure and/or size of plants can be very beneficial in a LED garden. S.C.R.O.G (screen of green), and S.O.G (sea of green) are common techniques to manage the shape and height of plants so that the light coverage is even, intense, and not wasted. Training plants laterally across a trellis allows many apical meristems (tops/colas) to grow, rather than just a few large ones. For this technique, trellis netting is installed horizontally above the plants, often at the beginning of flower, with more levels of netting installed above as needed. As the plant grows, it is woven through the mesh netting. There is no right or wrong way to trellis or "scrog", for example a garden could have 100 - 8" plants, or in the same space one large, trellised plant; both methods will produce very similar amounts. Regardless of the method, the goal remains the same, to maximize the production from the space and light.

12: Water Amount and Temperature

The temperature of the water or nutrient solution should be between 68° and 72° Fahrenheit. Using water chillers or heaters may be necessary to maintain this temperature. Water plants only when they need it. To see if they are dry, check the weight of the container, or feel down 2-3" for moisture. Only watering when needed will encourage good root development and avoid problems associated with overwatering. When the plants are ready to be watered, use enough water to saturate the media, ideally with about 20% runoff, every time. Do not let water sit in saucers or trays, any stagnant water can be a breeding ground for disease.

9 thoughts on “Maximizing yield with LED grow lights”

  • Chris S.

    Stay Cool, Stay Green, and Stay Inspired...

  • Jason P

    Thanks for putting this all together in one concise area! There is one other element I hear a lot of discussion about, maximizing photon absorption. What research have you guys found or done about the true necessity of reflective sides or flooring and the different materials that are out there like Mylar, Panda, and Orca films?

    • Kevin

      Our experience has shown that reflective materials on the floor and especially the walls has a huge impact in growing, not only in the total amount of light your plants get but also how it is distributed. Surrounding your grow area with reflective materials helps to get a more even distribution of light through the plants, so that leaves or plants on the outside of the lighting footprint grow more like the ones in the center.

      While reflective materials aren't a strict necessity, they are one of the cheapest, easiest ways to boost your yield.

      What we think of as being the best reflectors (mirrors and mylar) aren't actually reflecting as much light as you'd think; Orca film is the best for reflecting light, followed by flat (not glossy) white paint, then Panda film, then mylar. While Orca film is a little more expensive up-front, it is much sturdier and easier to clean than any of the other options, and will last many years longer than any other reflective material I've ever tried. It is also light-tight if you're trying to make sure your garden doesn't have any light leaks.

  • Khalil Naim

    Can some one tell me how high above the plant tops a LED light should be at? I have the BD450U I bought from Costco. Currently, I have about 6-8 inches of space between my light and the top of my plant. Is that too close? This light generates more heat than my other LED light which was very weak.

    • Kevin

      Our lights are a lot more powerful than most LED lights. For the BD450-U, we recommend hanging the light 25 inches above the tops of the plants for vegetative growth, and 18 inches above the plants for flower. At 6-8 inches you're not going to get the full footprint width, and may start to see signs of too much light with leaves turning white. Back it up to 18 inches above the average top of the plants and everything will grow better.

      Each model of our Universal Series lights have different recommended hanging distances to achieve the full flowering or vegetative footprint. These heights are given on the page describing each model light, just under the footprint diagram, so click here and choose your light model to see the recommended hanging heights.

      Please note that these are recommended heights and if you are using a light mover or adjusting the light intensity (for more or less light) the heights should be adjusted accordingly. Hanging the light higher will decrease intensity and give a larger footprint, and hanging the light lower will increase intensity but decrease the footprint. Please call us with any specific height questions for your own setup.

  • jon

    Will black dog leds flower on a moving light rail?

    • Kevin

      Absolutely! We recommend using light movers and we offer the Light Rail 3.5 with our lights. Light movers help eliminate shadowing of lower leaves and provide more even lighting to all leaves, increasing your yield.

  • Jake

    Can anyone tell me why your room or tent should be running at 83-85 F when the LED lights are on? Is there something different about the LED spectrum that requires it to run hotter than hps? Many grow guides advise against going above 80F in your grow space. Am I missing something here?

    (3: Temperature
    When growing with LED grow lights, the air in your room should be 83-85 °F when the lights are on (daytime). In a standard HID light setup, 75-76 °F is typical when not supplementing with CO2.)

    • Kevin


      With our Phyto-Genesis Spectrum™ the leaves aren't being warmed up by colors of light that plants can't use efficiently, causing the leaves to remain cooler. Plants need their leaves to be within a particular temperature range to metabolize most efficiently; they really don't care about the ambient temperature except in how it affects the leaf surface temperature itself.
      So with our more-efficient plant lighting spectrum, you need to run 9-10 °F warmer than you do with "white" light for the plants' leaves to be the same, ideal temperature. We have a lot more information on this in our leaf surface temperature study here.

Leave a Reply