LED grow lights

 

Whether you’re starting with growing plants indoors or you’ve used grow lights before, LED grow light is something that could help you. 

LEDs are rapidly becoming the most popular grow light in the industry. The benefits of LEDs are better energy efficiency, longer life-time, less heat output, and control over the spectrum. Recently they have started to become much more affordable as well. 
 
We’ve compiled this article for people at home, so you’ll have a basic understanding of LED grow lights for plants at home. If you’re a commercial grower you might like to check out our professional resources.
 

In this article:

1. What are LEDs?
2. Are LEDs right for you?
3. What types of grow lights are out there? 
4. Managing plant growth with LEDs?

1: What are LEDs?

Takeaways

• LEDs are Light Emitting Diodes which are electrical components that emit light. They can vary in size, color, and intensity. 
• Solid-state lighting (SSL) is another name for LED lighting.
• LED lighting can save growers around 50% on lighting electricity costs.
• LED Grow Light fixtures do not generate as much heat as HID fixtures. Therefore plants can be much closer to the LED fixture compared to HID fixtures and save space.
• Special spectrum LEDs can stimulate better plant health and growth
• Grow lights with the right spectrum enable growers to manage plant morphology, flowering, and influence flavor, and color.

 

What is a Light-Emitting Diode (LED)?

LED stands for “Light Emitting Diode”. In short, it is a semiconductor that is emitting light when an electrical current passes through it. LEDs are available in all sorts of sizes. It can be tiny such as 3mm or 5mm. These LEDs are mounted on a printed circuit board (PCB) which is assembled in a light source (e.g. lamp) or case or housing (e.g. lighting fixture). 

 
The brightness of an LED and the color that is emitted by the LED is dependent upon its power and specification within the electromagnetic spectrum. Note that humans perceive white light as very bright. This is because it contains a relatively large amount of green and less blue and red. Plants however require other colors. So light that are bright for the human eye are not necessarily bright for plants and vice-a-verse.
 

What is solid-state lighting?

A light-emitting diode is solid-state lighting. An SSL emits light from a piece of solid matter. Previously light was emitted from a vacuum-like incandescent bulb or in a gas like a high-pressure sodium bulb. LEDs do not use a hot wire to generate light or gas. LEDs use an electrical way of generating light and are therefore more energy efficient.
 

The energy-efficiency benefits of LED lighting

If you're using grow lights or have some experience with it, you might know that lighting can take quite some energy. LED lighting can save growers up to 50% on lighting electricity costs. There are two main reasons for this. The first reason is that LEDs consume a lot less energy to generate the same amount of light compared to traditional lights. For example, in a tungsten light source, the wire is made hot and when it is hot it illuminates light. LEDs don't need to generate heat as a requirement to make light, hence they are more efficient. The second reason is that LEDs can be made with a certain spectrum. Using a spectrum that is relevant for plant growth (photosynthesis) will help to make sure that energy is used effectively for plant growth. 
 

The lower heat output of LEDs

Incandescent lights or HID lights generate heat as a by-product of making light. But LEDs won't generate the same amount of heat, therefore, saving you costs of HVAC. Moreover, the LED light beam is cold which allows you to place the light very close to the plant. Whereas the light beam from HID might be warm, hence HID fixtures often need to be placed at a distance to avoid plant stress and tip burn. The LED fixtures will generate some heat, because the diode dissipates heat onto the heatsink in the lamp or fixture. Most of this heat is dissipated upwards, but if you’re placing grow lights very near plants the plants may still perceive some warmth. 
With LED lights you can save space and HVAC costs.
 

The optimized spectrum of LEDs

LEDs enable manufacturers to develop special spectrums to stimulate biochemical pathways. For example lighting can be optimized for plant growth and supporting the photosynthesis. Or it can be optimized to support plant development such as rooting, germination, morphology. It can also be optimized to elongate plants or manage the flowering for short-day plants and long-day plants. In plant tissue culture it can help to improve the multiplication, rooting and growth. e.g. Banana researchers worked with HortiPower to improve rooting in banana plants and have a 30% better growth.
 

The benefits of flexible-spectrum LEDs

Flexible spectrums enable growers to manage plant photosynthesis, plant morphology, flowering, flavor, color, and many other factors. Vegetable growers use flexible spectrums to improve the flavor and color of their produce. Flower growers can use the light spectrum to manage flowering time. E.g. long day plants can flower earlier and short-day plants can flower later so they can grow taller and become more desirable.
 

The benefit of quality lights

LEDs can offer a more consistent light output and quality than fluorescent and HID lights. With this improved performance and consistency, commercial growers and scientists see better results and higher quality plants. 

Improved crop quality

Vegetable growers appreciate the improved crop quality under LED fixtures. They report that flavor, color (and marketability) or shelf-life can be improved with good LED lighting. Using the right lighting can also speed up the turn times, enabling you to harvest more than you would without LED grow lights.
 

2: Are LEDs right for you?

Takeaways

• LED grow light gives you possibilities to improve crop growth all year round
• You can grow micro-greens, leafy greens, herbs, berries and many other plants all-year-round with the right grow light
• Fruiting vegetables need a lot more lights as they are light-loving crops
• Choosing the right power and spectrum is important, ask for help if you need
• There are flexible spectrum lights and there are also all-purpose grow lights. Choose what will work best for you

 

Choosing the right lighting technology

Choosing a light source is an important decision for indoor growers. 
There are three big types of lighting that you have to choose from:

1. LED (HortiPower)
2. High-pressure sodium (HPS or HID)
3. Fluorescent

As mentioned earlier, LED grow lights offer many more possibilities with regards to the spectral mix of the fixture to improve crop growth and grow all year round. Other lighting technologies like high-pressure sodium, metal halide, and fluorescent have a fixed spectrum. LEDs themselves also have a fixed spectrum, but they can be tailor-made and with light scripts from HortiPower you can make a unique light spectrum.
 
A HortiPower grow light provides a more balanced growth spectrum with a lot more blue and red light compared to an HPS or fluorescent fixture. Plants generally do well under HortiPower lights and can grow much stronger with better color, better roots, and generally healthier. HPS and fluorescent lights waste electricity by providing a light output that isn’t as effective for plant growth. This is because they are primarily made to help people see (light) instead of helping plants to grow. Moreover, HPS fixtures have an infrared spike which adds a large heat load and can cause plants to grow thin. 
Fluorescent lighting provides a relatively good amount of blue for crop growth. However, it is lacking in the red region which is also very important for photosynthesis.
 
HID and fluorescent lighting also contain mercury. When the light breaks it can release vapor that can be inhaled. Therefore it is considered hazardous waste. LEDs do not contain any mercury.
 
Where to use grow lights?
You can use growth lights to grow microgreens such as cress; herbs such as mint, basil; leafy greens such as baby spinach, lettuce, kale; berries such as strawberries, blueberries; propagate fruiting vegetables such as cucumber, tomato, bell pepper, and more. The exact type of grow light and the quantity you’ll need depends on your crop and where you’ll grow. 
 
Generally, it is recommended to use grow lights indoors in a dry environment. If you have some windowsill where you can put grow lights or a shelf with grow lights that would work well. A garden greenhouse would work great as well especially if you’re growing light-loving crops such as tomatoes. Typically in the garden greenhouse, you’ll need a high intensity to grow light. A grow tent is also a great environment to grow without any natural daylight.

How long should I use grow lights each day?

This depends on the crop and purpose, in general you should use them around 12hours a day, just like the sun. This enables plants to grow during the day and rest at night. 

3. What types of grow lights are out there? Can you grow with 600W lights and USB grow lights?

There are a lot of different grow lights out in the market. So here are some notes to help you.

Takeaways

• The type of grow light you’ll need depends on what you are growing and your goal.
• You can grow herbs, microgreens, leafy vegetables, berries, and more with the HortiPower Nurser range.
• Fruiting vegetables grow up well under grow lights but need high-intensity light for flowering and fruiting
• USB powered grow lights often emit too little light to support plant growth
• High power 600W grow lights are an option for grow-tent users and tech enthusiasts.
• White LED lights will give a good visual effect for people, but plants need other colors
• Use grow lights with plant-spectrums that are focused on giving you good plant growth and health

 

Grow herbs, microgreens, leafy vegetables, berries, and more

For propagation of plants such as herbs, microgreens, leafy greens, and berries you might need a fixture that can be placed at around 20-40cm distance with a micromole of up to 80 μmol/m²/s. μmol/m²/s is the intensity of light that is relevant for plant growth. It is the amount of light that reaches a surface (such as a plant leaf). The HortiPower Nurser 1 and 3 are perfect products for this. They are long (1.00 or 1.20 meter) and you’ll be able to place seedling trays or a hydroponic installation underneath. These lights are about 20 watts and you’ll be able to extend them or place multiple pieces next to each other. If you’re growing microgreens you might use 2pcs of HortiPower Nurser 3 together with the stand. If you’re growing leafy greens you might even go with 3pcs.
 
If you’re only having a tiny bit of space, the HortiPower Bloomer 2 might be a good choice. It is made to illuminate one plant at a 50-20cm distance. 
 

Fruiting vegetables

For fruiting vegetables such as tomato, bell pepper, and cucumber you can use grow lights to germinate and grow young plants. These crops are light-loving crops and if you’d like to have them flower and fruit as well, you’ll need a lot of light. These grow lights are typically more sought after by commercial growers. If you’re growing them fully indoor without any natural light you could use 15pcs of Nurser 3 on a 1.2m x 1.2m grow tent. This will give a lot of light more than 300 μmol/m²/s. If you have a garden greenhouse you can also grow the young plants indoors during wintertime and plant them in the greenhouse during spring and summertime.
 

USB powered grow lights

These USB lights look cute, but oftentimes the light output in μmol/s is just too little to make a meaningful impact on your plant growth or production. Normally a USB cable is about 5V, and the low voltage makes it difficult to generate a decent amount of plant-centric light. The HortiPower grow lights operate at 24V and the Nurser 3 has 100-240VAC input, which can drive more watts to the LEDs so they'll work harder for you and your plants have more light. 
 

High-power 600W grow lights

High power 600W grow lights are popular in grow tents, most of these are still traditional HID and sometimes LED lights. These lights consume a lot of energy and can make economic sense if the energy is free (e.g. with your solar panels) or you’re using these lights to produce commercially. Some of these lights are used in grow tents in cannabis production. Depending on which jurisdiction you are in, that might be a possible use-case. For most home growers that grow veggies and fruits, there might be better options available than a 600W grow light.
 
For commercial growers, HortiPower has a Grower that is 190W which is great for in the greenhouse. However, installation should be done by a licensed electrician and home growers might find the control options and the many possibilities to adjust the light more than you need. But if you're a scientist or a tech enthusiast you might love these even in a grow tent.
 

What about white-colored grow lights?

Some shops promote fully white ‘grow’ lights, but these lights are not special grow lights, they are white LEDs that are also used in normal home lighting or commercial lighting and marketed as grow lights. The price is relatively cheap but they might lack e.g. deep red and the full plant-spectrum that you might need. Chances are that if the light is made for people, the lighting distribution and other quality of light factors are also suboptimal for plants.
 

What about purple-colored grow lights? 

Purple grow lights are what you’ll see with our human eye and it is often a mixture of blue and red which makes purple. The first generation grows lights often contained blue and red and didn’t include other LEDs to cut costs. Today technology has evolved and with other colors, the plants grow even better. 
 

Flexible-spectrums

The HortiPower Nurser 1 has Deep Red, Green, Blue, White, and Far Red which can be independently adjusted. According to a report made in collaboration with Wageningen University, this dynamic spectrum can enhance yield and quality. This has also been confirmed by growers that use HortiPower commercially to cultivate banana, pineapple, and strawberries.
 

What about red?

For plants, deep red is very important. The red light that plants would need is different than the red light that is normally used in a color-changing bulb at homes such as the Philips HUE or LIFX. The red that plants are called deep red and a bit more expensive to produce than normal red LEDs. So when you're purchasing grow lights make sure you’re getting the right plant-centric red light.
 

All-purpose growth

If you’re looking for a plug-and-play light source you might like to check out HortiPower Nurser 3. This spectrum contains Deep Red, Green, Blue, and White that is generated with special spectrum LEDs. With this grow light you won’t need to adjust the spectrum since it is made after years of research and pilot projects in the various plant labs with amazing results.
 
Think of grow light as nutrition, more balanced nutrition will be better for health and wellbeing; it is the same with grow lights, a balanced spectrum will help your plants to grow better and happier. And yes, young plants need little light and they would like more as they grow up.
 

Lighting considerations

Here are some considerations:
Planning: based on your goals as a grower

1. Are you looking for grow lights that help you grow without any natural daylight or supplemental lighting?
2. What crops are you growing?
3. Are you propagating plants (for production of e.g. vegetables) or are you growing them more to maintain health (decorative)

Installation: safe and proper installation

1. Do you have electricity where you’d like to grow?
2. Lighting support structure (something to mount or fix the lights on)

Other growth factors: 

1. Temperature (Heating and cooling)
2. Nutrients
3. Humidity
4. CO2

Production: evaluate and tell us

1. Monitor crop quality
2. Collect data on cycle times and yield
3. Are you happy? Any feedback from your customers or friends and family? 

By the way @moestuin_avontuinier made an amazing comparison that I think you'll like to see:

4: Managing Plant Growth with LEDs

Takeaways

• Growing greens and herbs with LED lights can be beneficial for both energy saving and plant production and plant health. 
• With LED grow lights, you can save a tremendous amount of energy, they’re another tool for you to manage plant growth, and they enable you to get more consistent growth. 
• You can manage plant morphology (short and bushy vs tall and skinny) with growth lights, and you can also influence nutrition and taste

Growing greens and herbs with LED lighting

Some factors to consider when growing greens and herbs with LED lighting:

• Light quality can give an increase in flavor, antioxidant levels, darker leaf color, and plant morphology manipulation. It can also help to prolong the freshness during shelf-life (e.g. after cutting the greens).
• Plant morphology: light influences the size of the leaves, the height of the plant, the compactness of plants, and the root mass.
• Temperature: LED lights will reduce the ambient temperature compared to HID lights and it allows for less evapotranspiration and water consumption. 

• Nutrient mix: concentration levels remain similar to those when using traditional lighting. If you’re increasing your light intensity to boost photosynthesis the plants may need a bit more nutrients as well.  

What else can be improved by managing light quality?

Manage hypocotyl lengths

• With different light spectrums you could influence the heights and leaf curling in plants e.g. with different red and blue ratios.

Increase health-promoting phytonutrients and taste

• Adding relatively more blue light toward the end of the growth phase increases the phytonutrients that are available in the plant.
• Get deeper colors 
• Get higher quality plants (longer roots, more compact, crunchier)
• Manage flowering time (get an early harvest, get extra harvest)
• Optimize spectrum for biomass and morphology (e.g. lettuce)

The ability to adjust grow lights to the plant needs and grower's goal offers great potential for growers, who can customize crops for specific customers, and purposes. Experiment with what works for you and learn how that control takes place!
 

To recap this article, LEDs grow lights offer:

• Energy bill savings from both fixture efficiency a reduced heat load and reduced maintenance costs
• Ability to grow plants all-year-round including herbs, leafy greens, berries, and young fruiting vegetable plants 
• With the light you’ll be able to optimize for crop growth and crop health with special grow lights through all-purpose spectrums such as HortiPower Nurser 3 or fine-tune light with HortiPower Nurser 1
• Ability to get healthy plants with lots of roots, strong meristems, healthy colors, good taste, and more

For Home users check out these grow lights.

For Professional users check out these grow lights.