MarsHydrofactory
Well-Known Member
What Are The Hanging Heights For My LED Grow Lights?
— The Perfect Grow Light Height For The "Highest" Weed—
— The Perfect Grow Light Height For The "Highest" Weed—
Choosing the right height to hang your LED grow lights isn't straightforward. Even though manufacturers will give you a "general guide" for hanging LEDs, you have to consider many factors before making a decision. Most notably, you must determine how your hanging height will affect your LED grow light's intensity.
As you review our strategies to determine you grow light's height, please never forget the central goal: Provide optimal light penetration without burning your buds. While it may be tedious to tinker with your LED grow light's height and intensity, these efforts will pay off with healthy and bountiful buds.
Before Hanging An LED, Consider The Perfect PPFD
The first step to figuring out your LED grow light's hanging height is to review weed's preferred light intensity. Most significantly, you need to check the photosynthetic photon flux density (PPFD).
The ideal amount of PPFD for cannabis depends on its stage of development. For quick reference, here are the recommended PPFD ranges for marijuana:
- Seedling: 100 - 300 μmol/m2/s
- Vegetative: 400 - 600 μmol/m2/s
- Flowering: 800 - 1,000 μmol/m2/s
Just be sure the central PPFD estimates don't exceed 2,000 μmol/m2/s.
If you'd like to learn more on PPFD scores, read this previous Mars Hydro tutorial.
Side Note: Does CO2 Exposure Alter The Ideal Height For LED Lights?
Since we just mentioned CO2 supplementation, it's worth noting both the PPFD and DLI scores should be higher with extra CO2 exposure. When you give your cannabis plants more CO2, they can handle more intense light and heat. If you don't ramp up the light intensity in your space, you won't be enjoying the benefits CO2 provides.
From a height perspective, you could hang your grow lights lower to increase PPFD scores. Some cannabis cultivators who use CO2 supplementation say it's OK to start as close as 16" with grow lights and even move as close as 8". At max, most cannabis strains could benefit from ~ 2,100 PPFD.
It would help if you read this previous Mars Hydro post for a detailed explanation of using CO2.
So, What Are The Height Recommendations For Non-Dimmable LED Grow Lights?
The perfect height for your LED grows light is dependent on multiple factors, including the light's average intensity and your plant's maturity, as well as the temperature of the plant leaves.
Thus, the LED grow light hanging distances for a non-dimmable LED are as follows:
- Hang your LED grow lights between 20" - 30" above seedlings.
- As your plants reach vegetative growth, move your LEDs down to about 18".
- To improve trichome production, try lowering LEDs to 16" during flowering.
Look at the LED manufacturer's recommended heights for the best advice when setting up your grow room. If possible, you should also test your LED grow light with a PPFD scanner so you can calculate the average PPFD your plants will receive throughout your space.
Will Hanging Heights Differ For Dimmable LED Grow Lights?
LED grow lights with a dimmer have more leeway than non-dimmable LEDs. Since growers could adjust the light intensity with the flick of a switch, you could fix your light’s hanging height and save more electricity bills.
Dimmers are particularly useful during the seedling and vegetative stages. During these early stages of growth, cannabis plants are more sensitive to lightwaves than during flowering. By contrast, the full intensity of Mars Hydro's LEDs helps stimulate extra trichome production once cannabis buds emerge.
Here's a general LED hanging height guide for dimmable LED grows lights for the first time:
- Hang your LED grow lights at 18" - 24" at 25 percent intensity for seedlings.
- Bring your LEDs to about 18" during vegetation and set the dimmer to 50 percent.
- Keep your LEDs at 18" and turn them to full intensity.
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