The hanging heights and dimmer settings of led grow lights at different stages

Choosing the right light distance 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 your grow light's height, please never forget the central goal: Provide optimal light penetration withoutburning your plants. 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 Plants' preferred light intensity. Most significantly, you need to check the photosynthetic photon flux density (PPFD).

The ideal amount of PPFD for plants depends on their stage of development. For quick reference, here are the recommended PPFD ranges for plants:

  • Seedling: 100 - 300 μmol/m2/s
  • Vegetative: 400 - 600 μmol/m2/s
  • Flowering: 800 - 1,000 μmol/m2/s

Take a look at the estimated numbers at different heights on your manufacturer’s PPFD maps. You could add these scores and divide them by the number of ranges you collected to get an average PPFD.

Just be sure the central PPFD estimates don't exceed 2,000 μmol/m2/s.


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 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 plant 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 plant strains could benefit from ~ 2,100 PPFD.


So, What Are The Light Distance For Non-Dimmable LED Grow Lights?

The perfect height for your LED grow 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 production, try lowering LEDs to 16" during flowering.

Please use these height suggestions as a general guideline. The intensity of your LED grow light may alter how close you can position these diodes to your plants. And make sure the Plants leaf temperature is below 30 Degree Celsius.

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 Light Distance 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. While you switch energy and save electricity, you don't have to compromise on intensity and quality.

Dimmers are particularly useful during the seedling and vegetative stages. During these early stages of growth, plants are more sensitive to light waves than during flowering. By contrast, the full intensity of Mars Hydro's LEDs helps stimulate extra production once plant buds emerge.

Here's a general LED hanging height guide for common dimmable LED grow lights (if you're not using Mars Hydro) 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.


Mars Hydro Recommended Light Hanging Height and Dimmer Setting

If you're using a Mars Hydro dimmable LED grow light, the first thing you need to know is that the percentage on your dimmer corresponds to the max PPFD. For example, if you put your LED grow light at 50 percent, the total PPFD score will be 50 percent. Please factor this into your PPFD and DLI calculations at different stages of growth.

For people who use Mars Hydro's TS, FC, or FC-E models, we'd suggest placing them ~ 6" higher than the recommended height (in the below chart pics). This extra space will prevent the risk of burning your seedling as you experiment with the ideal PPFD. You could move these lights down to as close as 12" during flowering as long as your leaves can resist.

People with a Mars Hydro SP Series LED grow light should start at 20" and only work down to 16" by flowering.

We'd encourage growers to stick to the following dimmer settings for different stages of development:

  • Seedling to pre-veg: 25 - 50 percent
  • Vegetation to pre-flowering: 50 - 75 percent
  • Full flowering: 100 percent


Mars Hydro LED Grow Light Distance Chart And Dimmer Setting

The above are tips to hang and dim most of the grow lights on the market.Mars Hydrois also a LED grow light manufacturer, so here we’d offer the Mars Hydro LED Grow Light Distance Chart and Dimmer Setting Chart.

Please note:The hanging heights and dimmer settings in the charts below are the optimal levels where the PPFD numbers will be the best and most evenly distributed. However, if you are a first-time user, please follow the above "What does Mars Hydro recommend for its dimmable LED grow lights?" section to reserve some distance for your plants to acclimate to the light distance setting and for you to prepare a compatible environment. However, if you're familiar with Mars Hydro LEDs, please feel free to try the best distance and dimmer settings.

mars hydro ts series led grow light distance and dimming setting

mars hydro sp series led grow light distance and dimmer setting

The mars hydro fc hanging height light distance

mars hydro fc-e series led grow lights hanging height and dimmer settings


Why Dimmable Mars Hydro LEDs Are Always Worth It!

You could argue that dimmers aren't "necessary" in LED grow lights. However, once you try a dimmable Mars Hydro LED grow light, you'll be amazed at how much time, money, and aggravation this feature saves you. A dimmer will provide customizable light penetration andpull less energy to save electric bills. 

To learn more about why Mars Hydro's dimmable LEDs are worth your money, read through this previous blog.