How Far Should LED Grow Lights Be From Plants

There are various ways to take care of your indoor plants. One way is to use LED grow lights. However, using these lights does not have the same effect when using traditional light sources, such as the sun. Though, they have in common that there should be a specific distance between the plants and the lights.

Whether you’re new to using grow lights or want to deepen your knowledge on operating them, you’ll need to learn how far LED grow lights should be from plants. Fortunately, we’ll be sharing all of that, along with other tips and mistakes to avoid, in this article.

Why Distance Is so Important For Indoor Plants

What’s the big deal with distance? Does the distance of the lights to your plants affect plant growth and performance? The answer is yes. Think about it. Indoor plants aren’t getting natural sunlight outdoors, so the indoor light must emulate natural lighting during the growth cycle.

However, the intensity and distance have an impact on the plants’ overall health. Therefore, the lights need to be at the proper distance. Otherwise, you either won’t encounter any growth or experience bleached/burnt leaves on your plants.

The Different Types of LED Grow Lights

Before we consider how far away from your plants the lights should be, let’s look at the different types of grow lights available.

Purple Lights

These are the standard LED grow lights and are widely available on the market. This type of LED light contains several hundreds of small-medium wattage LEDs. The biggest benefit of this type of LED light is that they’re budget-friendly. However, they can sometimes be unreliable and, due to popular demand, you’ll need to research the best brands and products to avoid lower yields.

COB Light

Next, this type of LED light consists of hundreds of small LEDs within one chip, unlike multi-coloured LEDs with chips spread throughout the entire fixture. More efficient than LEDs, COBs provide excellent penetration into the plant and offer a light spectrum for healthy and efficient growth. But, on the other hand, this type of light can be fairly expensive.

Spread-Style LED

Finally, spread-style LED lighting has an abundance of small LEDs spread throughout the panel and is often used in commercial greenhouses. The biggest advantage of this type of LED light is its energy efficiency, which means you can obtain a lot of light for the wattage that you use. However, the type of light can also be expensive.

How Far Should LED Grow Lights Be From Plants?

As a general rule, you should position your LED grow lights between 12 and 30 inches from the top of your plants. However, as your plants grow, you may need to adjust the height to prevent them from touching the LED lights or burning the leaves.

However, the main consideration you should make when deciphering the distance from plants is the wattage. The higher watt your LED lights, the further away the plants will need to be. On the other hand, lower-watt lights can be placed closer to your plants.

If this seems a little confusing, here’s a rough guideline for the distance from the top of the plants to the grow lights.

  • 200–399 wattage: 12–20 inches
  • 400–599 wattage: 20–27 inches
  • 600–799 wattage: 30–38 inches
  • 800–999 wattage: 32–42 inches
  • 1,000+ wattage: 36–46 inches

Different Distances Depending on the Stages

With that being said, you may need to manoeuvre and adjust the LED grow light distance during the different stages of growth.

Seedling Stage

During this stage of growth, position the LED lights between 24–36 inches above the plant.

Vegetative Stage

During the vegetative stage, the grow lights will need to be positioned closer to your plants. This is because this stage requires about half the light as the final stage.

Flowering Stage

For the flowering stage, move the LED grow lights to their closest point to your plants. You’ll also want to increase the lighting intensity as you adjust from the vegetative stage to this stage of growth.

Signs of Burn on Your Plants

Although LED lights help your plants grow, it’s still your responsibility to check on the daily growing process. This ensures that you know your plants are getting enough light, or in the worst-case scenario, they’re getting too much light and becoming burnt. Here are some signs to look out for in this case.

If your plants have light bleaching and damage, their leaves will become to point upwards. You may also notice bleaching in the form of leaves that turn yellow while having veins that appear green. But this colour contrast is an apparent indication of light damage.

Additionally, the plants’ leaves might begin to curl up or thin outlines on the leaves’ exterior. Aside from moving the lights farther away from the plants, you can also improve ventilation in the room.

Common Mistakes When Using LED Grow Lights

Grow lights are a great way to grow indoor plants, but that doesn’t mean that everyone can use them. Take into consideration some common mistakes people make when using grow lights.

Not Adjusting Your Lights

We briefly mentioned earlier that you’d need to adjust the distance of the lights throughout the different flowering stages. But it’s a common mistake for people to forget to do this. So instead, you can end up with high-intensity light too close to your plants, leading to the symptoms above. You’ll also need to rotate your plants to ensure that no leaves are stretching towards the light.

Not Using Enough Lighting

Just because you have LED grow lights, it doesn’t mean that that’s enough to make your plants bloom without you doing anything else. Insufficient lighting is one of the most common mistakes when using grow lights. To prevent this from happening or to resolve a current situation, consider the number of plants you currently have and calculate an appropriate number of LED lights to light them appropriately. Make yourself aware of the light intensity, too. As an example, a 300W grow light will provide a yield of around 150 grams. Therefore, you’ll need to ensure that you have the perfect balance of lights without too much light intensity or not enough.

Using the Wrong Light Spectrum

Another common mishap that plant growers make is using the wrong light spectrum, such as using a blue spectrum when you need a full spectrum. For plants to grow to their best capability, they require different types of lighting throughout different growth stages. Fortunately, full-spectrum lights make this achievable. However, if you use them in the wrong setting at the plant’s wrong growth stage, you won’t experience the best growth that you could. As an example, during the vegetative stage, plants grow better with a blue spectrum. So, if your grow lights emit a red spectrum, it’ll impact the plant’s growth.

Not Taking Care of Your LED Grow Lights

LED lights require maintenance and proper care for them to perform at their best. Partake in general caring, such as using a glass cleaner to remove any dust or debris that’s stuck on the surface. We also recommend setting up a power stabilizer to connect to your LED lights to create an equal incoming voltage. Doing this will help to protect the chip inside of the LED lights.

Not Taking Into Consideration Other Factors

Looking after LED lights isn’t just about focusing on how the grow lights operate. It would help if you also considered external factors, such as the room temperature, soil, nutrients, airflow circulation, and much more. There are several factors to keep in your mind when growing indoor plants, and these can affect the amount of light that your plants need at any given time.

Tips for Using LED Grow Lights

Now that we’ve talked about common mistakes people make with grow lights, let’s consider using grow lights properly with these tips.

Keep Your Eye on the Temperature

Fortunately, LED lights don’t emit heat as other lights do, but they do produce some. So it would help if you managed this temperature because the room’s temperature can fluctuate at any time, affecting the LED lights’ temperature as a result. The best scenario is to have a programmable thermostat in your home that automatically adjusts the temperature in your home for optimum comfort. But if you don’t have a thermostat, you may need a manual thermometer in the room near the plants to keep your eye on the temperature. You can then take action accordingly when needed.

Create a Schedule

We mentioned earlier that you’d need to adjust the light intensity and the distance of the grow lights to your plants, and the best way to keep on top of managing that is by setting a schedule. Having a schedule and routine to follow that your plants experience the same amount of light since the light towards the middle of the LED lights is more intense, so you’ll need to rotate them often. However, if you don’t know how often the plants need rotating, we recommend doing this once a week.

Check the Water Every Day

Plants need water to grow, but it’s so easy for people to make the mistake of giving their plants the incorrect amount of water. Not giving your plants enough water means that the soil will dry out quickly, and, as LED lights let off some heat (albeit not a lot), a grow light can also affect the soil’s moisture levels. In addition, your indoor air conditioning or heating unit will also have a part to play in the overall humidity levels. When it’s winter, the air in your home will become drier, contributing to the soil drying out more. To ensure your soil has the correct moisture levels, you need to monitor the soil’s consistency daily. Doing this will also give you some clues on how your habits, such as switching up the thermostat, can affect your plant’s moisture levels. The key is consistency.

Invest in a Timer

Growing indoor plants require a lot of hard work and investment in your time. But you can make the process easier for yourself by investing in a timer. Plants don’t need to be lit 24/7, and, like other living things, having a moment to rest is a good thing. Aim to keep your plants in darkness for around six hours a day to mimic the natural lighting of day and night. A timer means that the lights automatically switch on and off at appropriate times without you having to manage that manually.

Growing Seedlings Using LED Grow Lights

Beginners make some common errors when trying to grow seedlings, such as giving enough lighting, placing the lights too far from the seedlings, switching off the leaves too early, and not allowing enough light.

Amount of Light Required

The first thing you’ll want to consider is how much light they need. Although the notion behind how many light seedlings need might be complex, the overall goal is to provide 120–150 micromoles of PAR (photosynthetically active radiation) to your seedlings.

Fortunately, you don’t need to work out formulas to get your answer because you can remember that, for LED bars, keep the grow light 8–12 inches away from the seedlings. Or 5–6 inches for T5 fluorescent lights.

Light Coverage

The next important factor to consider is the amount of LED grow light coverage you’ll need for your seedlings. For LED bars, keep each light 8–10 inches away from each other, and for T5 fluorescents, four to five inches apart from one another. Following this structure ensures an equal amount of light intensity across the entire tray of seedlings.

Do You Have Any Tips for Grow Light Distance?

Now that you’ve heard from us about what you need for proper plant growth and how far LED grow lights should be from plants, you should do your research and ensure that your plants are getting the care they need.

We’d love to hear any feedback, tips, or recommendations you have on using an LED grow light system or general advice on caring for your indoor plants. Share what you know in the comments.

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