Can Aquarium Plants Grow With LED Lights?

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As an aquarist, I enjoy growing foliage in my aquarium. However, quite frequently, I’ve been asking myself whether aquarium plants can grow with LED lights. The longer I experimented and researched the topic, the better understanding I got about the topic. Now, I am willing to share my conclusions.

Aquarium plants can grow with LED lights, as long as they are exposed to the right lightning intensity and color temperature; 6500 to 10000 Kelvins. Adjusting the LED system to the tank’s depth and surface area will allow the plants to perform photosynthesis by exploiting dissolved CO2 residues.

As we move forward in this article, I will share the right lightning intensities for the most prevalent aquatic plants. I will also present the precise LED lighting system that I use and explain how to maximize plant growth while avoiding unwanted algae.

Can LED Lights Grow Aquarium Plants?

LED lights can grow aquarium plants. However, while plants serve various purposes in a tank, they are among the more complex elements of an aquarium. That is especially true when it comes to keeping them alive. Lighting issues are incredibly confusing because of their connection to algae.

LED lights are supposed to simplify matters because they are affordable, flexible, and you can find them in various colors. That being said, you cannot pair your tank with any random LED light you encounter on the market, not without understanding the following:

Because LED lights are so diverse, most prominent aquatic plant species will grow under the right LED lights. People whose plants have died despite LED lights’ presence tend to match the wrong plants to the wrong lights. In most cases, it is a question of intensity.

That is to say; some plants require a lot more light than others. Before selecting and purchasing an LED lighting system, you should first determine whether your plants are low, moderate, or high-light.

Here is a convenient table that relates prevalent plants to their lightning requirements:

Low LightAnubias, Sagittaria, Java Moss, Java Fern
Moderate LightDwarf Sagittaria, Bacopa Monnieri
High LightRotala Wallichii and Macrandra
  • Low Light Plants

As their name suggests, low-light plants are easy to maintain. They don’t require that much light to thrive. They include Anubias, Sagittaria, Java Moss, and Java Fern. New aquarists are encouraged to experiment with low-light plants when they start because they are easy to care for.

  • Moderate Light Plants

Low-light plants will grow under moderate light conditions. However, because they don’t require that much light, moderate light will cause them to multiply at a rapid rate, eventually crowding your tank.

That is why you are encouraged to match the lighting to the plants. Moderate-light plants like the Dwarf Sagittaria and Bacopa Monnieri are better suited to moderate lighting conditions because they will grow at a more controlled pace. Naturally, they require more work than low-light plants.

  • High Light Plants

The most difficult species to maintain are those that require a lot of light. They include Rotala Wallichii and Macrandra. These species will develop beautiful and vibrant leaves under the right lighting conditions. But they also require additional components such as the injection of CO2. 

It should be noted that metal halides do a better job of nourishing high-light intensity plants. LEDs are more suited to moderate and low-light plants, though you can still pair them with high-light intensity species.

You can grow most plants under any lighting conditions you encounter in the tank. That includes high-light plants. They will grow in low-light conditions if you give them an abundance of CO2. However, you are better off matching the lighting conditions to the plants. Ultimately, your choice will depend on the amount of maintenance you want to do.

Why Using LED Lights for Aquarium Plants?

As was noted above, plants require light to grow. The sun is a decent source of light for aquatic plants. But as you now know, direct sunlight is a danger because it encourages the growth of algae. LED lights are a suitable substitute because they can mimic the light generated by the sun.

The sun burns at 5800 Kelvin. A 5800K LED light doesn’t burn at 5800 kelvin like the sun. However, it can produce a light whose hue mirrors that of the sun and is bound to deliver the same benefits.

Yet, you don’t need a 5800K light to maintain the health of your aquatic plants. Any lighting system that comes within 1200k of that figure will do. And fortunately, LED bulbs are available in a variety of ratings. 

They offer minute control over the lighting needs of your tank. Some have features that enable aquarists to either dim or raise the intensity of the light. Admittedly, those attributes are common in other types of aquarium lighting, such as fluorescent bulbs. 

However, LED lighting stands out because it is long-lasting, and it generates very little heat. LEDs enable aquarists to illuminate their tanks without exposing the water to unwanted spikes in temperature.

What Kinds of LED Lights Are Good for Aquarium Plants?

Practically speaking, aquarium plants will grow in the presence of most LED lights on the market, mainly if the lights in question are targeted towards aquarium plants. Naturally, some models will do a better job of enriching your plants than others. 

If you’re in a rush, I will say now that my recommendation is the NICREW ClassicLED Aquarium Light (link to Amazon). After years of experiments, that is the only device that kept the delicate balance between healthy plant growth and algae inhibition.

But for the most part, you can get by with most brands. Yet, I highly suggest taking certain factors into account when selecting an LED lighting system, for instance:

1. Tank Size

The tank size is going to affect the intensity of the light you choose. That is because the size will determine the LED’s ability to reach the plant life. Lighting enthusiasts will encourage you to take the PAR (photosynthetic Active Radiation) into account when purchasing an aquarium light.

The PAR measures the strength of a light source with regards to its ability to stimulate plant growth.[1] You can use it to measure the intensity of an LED. However, the PAR is irrelevant unless it is measured against the tank size.

For instance, a device categorized by its manufacturer as an intense light will create only moderate lighting conditions in a tank that is too deep. That is because only a small partition of the device’s light will reach the bottom plants.

On the other hand, a moderate light could create decent light conditions in a shallow tank because so much of the light it generates reaches the bottom. That is why so many LED light manufacturers are hesitant to publish the PAR figures of their products. 

They understand that the PAR number is only relevant when contrasted against the size of the tank. Therefore, I highly recommend checking how the particular LED model you are considering performs in tanks like yours.

2. Spread

This factor is concerned with the dispersion of the light. Simply put, it refers to the space in the tank the light covers when you switch it on. You need a light whose spread will guarantee that all the aquarium plants receive the light they need.

However, the spread isn’t that critical because you can invest in multiple lights to ensure that every single plant in the tank is covered. The tank size is also vital in this area because it will determine the number of lights you need, not to mention their spread.

Many aquarists prioritize LED light bars because they cover the aquarium’s entire length, guaranteeing comprehensive coverage. If you get one of those, make sure to put it in the middle of the tank’s cover to avoid neglecting certain areas.

3. Spectrum & Timer

People use the kelvin rating to determine the spectrum or temperature of an LED aquarium light. As mentioned before, the goal is to find an LED light close to the sun (5800K). A full-spectrum LED light fixture can be relied upon to enrich your plants.

I also suggest getting a light fixture with a timer. Fish tanks need consistency, and you cannot afford to switch the lights in the tank on and off at random. That might induce stress in your fish. They expect roughly 12 hours of daylight and an equal amount of darkness. 

The configuration of your aquarium lights has to suit the fish as well as the plants. A timer will enable you to maintain consistency in this area. As a beginner, you might have to experiment to determine the right number of hours your plants require to thrive. 8-12 hours should do.

Personally, I don’t own an LED lighting system with a timer. However, if I had to get one, it would definitely be the Hygger Auto On-Off LED Aquarium Light (link to Amazon). All you have to do with that system is to set your timezone. The device will then adjust white lights during the day and dim those into blue lights during night hours (all that is done automatically).

Why is Light Important for Aquarium Plants?

Before you can appreciate LED lights’ attributes, you need to understand the critical role that light plays in aquatic plants’ lives. To plants, light is a source of fuel. Without light, photosynthesis cannot occur. 

However, it would help if you found a balance. That is to say; if you give the tank too much light, your plants will grow at a much faster pace (and so will the algae). But if the light is too little, the health of your plants will suffer.[2]

You must provide light in quantities that will encourage your plants’ growth without causing the algae population in the tank to explode. That is why the sun is so problematic. Plants in a tank that is exposed to direct sunlight will thrive. But so will the algae.[3] 

That is why artificial lighting is all the rage. LED lights provide more accurate control over your tank’s lighting requirements. Using a timer, you can limit the amount of light your plants receive to a few hours a day. That allows your plants to thrive while limiting the growth of algae.

What LED Color is Best for Plants?

Overall, the color of the LED light doesn’t matter for plants’ growth, not where the health of the plant is concerned.[4] Aesthetically speaking, many aquarists use red, blue, and green to make the colors of their plants pop.[5] But when it comes to growing aquatic plants, the colors don’t matter. 

Some aquarists are drawn to soft white LEDs because they are suitable for plants, but they don’t promote algae growth. Others have a preference for actinic blue because it is associated with vegetative growth.[6] 

Red is supposed to make plants grow taller and stringier. But an aquarist can produce a healthy population of aquatic plants using any color that suits them. It is more critical to provide the right lighting intensity rather than a specific color.

Will 6500K LED Grow Plants?

6500K LEDs will grow plants, although there is no ideal Kelvin value for nurturing foliage. The PAR value determines the efficacy of the LED light (at a particular depth). Therefore, most LED lights in the range of 6500-10000K can properly grow plants.

Some believe that merely 6500K lightning systems can promote photosynthesis. However, this isn’t true. The K value merely reveals the hue of the light.[7] It will tell you whether the color tone of the light is white, warm, or bluish. That doesn’t tell you the strength of the light or its ability to promote plant growth.

Do LED Lights Cause More Algae in an Aquarium?

LED lights do not promote more algae growth than incandescent, fluorescent, halogen, or plasma lighting. Exaggerated algae growth mainly occurs due to excessive light exposure, and the source is of lesser significance.

You will occasionally encounter anecdotes from aquarists who are confident that their tank algae started growing at a greater rate once they installed LED lights. But few of those aquarists have presented evidence to eliminate the possibility that other factors (other than the LED light fixtures) could have caused the algae to overgrow.[8]

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Aquarium plants can grow under LED lights, although that depends on the lightning’s intensity. When choosing a lighting system for an aquarium, one must consider the tank’s depth and how well the light will spread across it.

If the tank is properly illuminated during the day, the plants will use the LED lights’ energy to perform photosynthesis. That is done by exploiting CO2 residues in the water. The light’s color is less significant for that purpose, and it can range anywhere between 6500 and 10000 Kelvins.