Updated at: 27-10-2022 - By: Sienna Lewis

In the greenhouse, do you know how to utilize a growth light properly? Plants can only create energy and food if light is available to trigger photosynthesis.

Greenhouse hobbyists may utilize an artificial light source in order to provide a source of light for their plants. Known as “growing lights,” they can be found in a variety of shapes and sizes all around the world. These lights, on the other hand, necessitate careful consideration of several elements and considerations before they may be installed.

While it’s preferable to have direct sunshine in a greenhouse, when is it appropriate to utilize a growth light? We’ll talk about when a greenhouse grow light is a good idea in this article. To get the most out of your growth lights, be sure to follow all of the guidelines listed above.

Types Of Growing Lights

Three principal types of growth lights are classified by their primary role, which is to augment or completely replace sunlight in urban farming. Let’s have a look at the different varieties of greenhouse grow lights first.

Fluorescent growing lights

CFLs or Compact Fluorescent Lights (CFLs) are the most common form of these growing lights. Vegetables and herbs grown indoors can benefit from the bright light provided by these bulbs How effectively light is distributed among plants is directly related to how far away fluorescent lights are from the plants.

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HPS lights

High-pressure sodium, or HPS, lighting is only for the most experienced electricians. These yellow, heat-emitting bulbs have been around for over seven decades. They’re on the market, but they’re difficult to set up and inefficient at producing a steady, reliable light source.

LED lights

The most popular type of light source is an LED. In comparison to its two competitors, they use less light and produce less heat. These bulbs are excellent at directing light and emitting low to no heat. CFLs, on the other hand, are more affordable, but their efficiency is limited to a narrow range of wavelengths.

Growing Light For Your Greenhouse

The best time to employ different kinds of growing lights is now that you’ve learned about them. In this section of the blog, we’ll go over what to look for and what precautions to take before turning on your greenhouse lights.


Fast weather changes and an uncertain environment mean that the amount of sunlight we receive may be irregular. Plants in greenhouses need a lot of light to generate their food, and this inconsistency could harm their growth.

Growing lights are efficient when sunlight is inconsistent or unavailable, especially in the Northern areas during long and dark winter days. Although sunshine isn’t always available, these artificial devices can encourage the growth of your florae and provide them with the proper amount of photons.

Indoor greenhouse

There are some people who choose to keep their greenhouses indoors all year round. As a result, they rely on growing lights to provide light to their plants.

You should utilize a growing light system if your greenhouse will be indoors or in a location where it will not receive enough natural light. Your greenhouse would be more efficient if you continued to grow plants.


If you don’t know how to use something, you can’t benefit from it. Before putting these growing lights to use, consider what your greenhouse’s plants need based on the parameters listed above.

The spectrum of visible light is made up of all the hues of the rainbow. In order to boost their growth, plants make use of the red and blue ends of the spectrum. You need more than a simple lamp to mimic and minimize sunlight for your plants to grow.

Use blue and red light bulbs instead of white or yellow ones since they are more efficient.

Keep track of the time your plants spend under the growing lights because they are artificial. For the most part, most flowers and vegetables require 12 to 16 hours of light each day to thrive. The plants’ respiration cycle is dependent on darkness, thus going above that limit could throw their cycle off.

Equipment such as these must be set up correctly to ensure that the greenhouse receives adequate light. Growth will be slowed and development will be enhanced if the plants receive insufficient photons.

Finally, utilize lights that don’t generate a lot of heat in your greenhouse. Your plants’ vitamins and nutritional content could be affected by extreme temperatures, according to scientific findings. LED lights, which emit almost no heat when turned on, would be beneficial.

How To Use A Growing Light?

If you don’t use a growth light in a greenhouse correctly, your plants won’t grow properly. In this section, we’ll go through how to get the most out of a growing light.

#1 Use a light timer

Light in your greenhouse doesn’t have to be on 24 hours a day, seven days a week, no matter how many plants you have. It is recommended for you to use a light timer to control your lighting system’s on-and-off cycle.

#2 Position the lights properly

One to three feet is a good rule of thumb when using low-intensity light discharge growing lights. Lights with a higher luminosity should be set at least four to six feet distant from each other. For your florae’s benefit, evaluate and adjust the lighting to meet their specific needs.

Remember to put the lights in a way that ensures an even distribution of light. As a result, if you have a larger greenhouse, you’ll need a bulb that has higher wattage and provides more light for your plants.

When To Use A Growing Light In A Greenhouse Correctly

Supplementation needed

If a greenhouse is to be successful, it must offer the right amount of light for plants to undergo photosynthesis. Cornell Information Technologies says that in some cases, natural sunshine is sufficient for greenhouses. However, in rare situations, this might lead to temperature issues that negatively impact plants.

Because of this, greenhouses employ cooling equipment and lower lighting levels to maintain a constant temperature. Another issue that may arise as a result of this is a shortage of light. The plants will benefit from a growing light in this situation.

During the winter, a greenhouse’s need for an organic light becomes even more apparent. When it’s cloudy, light can’t get into greenhouses in the Northeast and Northwest of the United States. This is where a growth light will come in handy.

Young plants vs. mature plants

You’ll utilize a growing light in your greenhouse to help your plants grow to their full potential, as the name suggests. It’s important to keep in mind that the nutritional needs of various plants and vegetables vary. It was even noted by Michigan State University that light has an impact on fruit production.

When your seedlings begin to sprout, you’ll see how light levels affect their development. It will be feeble and have thin stems if the plant doesn’t get enough sunlight. There is no guarantee that the stem will thicken if it lives to adulthood.

In order to ensure that all of your plants’ leaves receive the same amount of light, you may need to increase the intensity of your growing lights. In addition, the sort of plants you’re growing in a greenhouse will have an impact on the amount of light you’ll require. Plants in the fruiting or flowering phase will require a growth light during months when there is less sunlight.

Tomatoes typically begin producing in North America at the end of October, which necessitates the usage of growth lights. Plants cultivated for their vegetative components may not necessitate the use of a growing light because they are already in this growth phase and will continue to do so. Even yet, the low light levels of winter may necessitate the use of a growing light to maintain plant development.

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How Long Should You Use A Growing Light In A Greenhouse?

The amount of light required by various plants varies, as previously indicated. A greenhouse grow light’s lifespan is determined by the plants it’s used to support. In order to make light scheduling easier, you might divide your plants into long and short-day groups.

When the day is long and the night is long, long-day plants will thrive, while short-day plants will thrive when the night is short. There are plants that flower even in the fall because of this. An organic light can also be used for short-day plants like herbs, which are grown for their vegetative phase.

Your greenhouse’s success is largely determined by the amount of light it can produce. Be aware of your crops’ specific lighting requirements while also keeping an eye on their other necessities. It’s also important to keep in mind that inadequate crop spacing can reduce the amount of light reaching your crops.

Can You Have Too Much Light In A Greenhouse?

A greenhouse must be kept at a constant temperature in order to avoid overheating and damaging the plants. When it comes to a successful greenhouse, light and temperature play an important role. Cooling systems, evaporative cooling, and shadings can be used to regulate greenhouse temperatures when too much light is present.

How to use grow lights for houseplants: What are grow lights?

Plants require light to grow, but not all light sources are the same. In every temperature, any time of year, you can grow gorgeous indoor plants thanks to growing lights! Grow lights come in a variety of shapes and sizes, all of which are designed to stimulate photosynthesis and encourage plant growth.

Science basics: What is photosynthesis?

Do you recall studying the process of photosynthesis in science class in the eighth grade? Let’s go back to the basics for a moment, shall we? Plants carry out a process known as photosynthesis. Plants can employ the chemical energy that is produced when light is converted into energy for growth. The process of photosynthesis differs among plants.

In order to thrive, plants need a variety of light wavelengths. Depending on its design, grow lights can either emit a spectrum similar to that of the sun’s or emit only the wavelengths necessary to support the growth of indoor plants. Foliage can benefit from blue light, whereas root and flower production benefit from red light.

What’s the difference between grow lights and traditional lights?

Grow lights and conventional lighting are not interchangeable, so how can you tell them apart? Wavelengths and heat. If your plants don’t get the correct amount of light, they won’t be able to perform photosynthesis. The heat produced by conventional lights can very easily scorch and burn plants.

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While grow lights help photosynthesis by providing a wide range of wavelengths and specialized lighting to meet your plant’s demands, fluorescent lights only provide a single wavelength. Grow lights, on the other hand, use less energy and do not produce heat, making them safer for your plants to use.

What are the different types of grow lights?

Grow light selection might be a challenge because there are so many varieties to choose from. Incandescent, fluorescent, LED, and HID are the most common types of grow lights.

1. Incandescent grow lights

These are the most common and least priced light bulbs; they can be purchased from a hardware or supermarket shop.. In a lamp, you’d find them to be the most common type of light bulb. Despite this, they aren’t the best option for a grow light because they produce a lot of heat that could burn your plants, and they aren’t particularly effective at conserving energy or lasting a long time.

2. Fluorescent grow lights

If you’ve ever seen a spiral bulb, you’ve probably seen a fluorescent light bulb in the form of a long tube. These bulbs are safe for your plants because they don’t produce a lot of heat. Additionally, the light they provide is pleasant to the sight.

Warm light for flowering and cool light for vegetation can be produced by using fluorescent lights. Fluorescents are generally more expensive than incandescent bulbs. Because they are long-lasting and energy-efficient, they are a good investment.

3. LED grow lights

The term “LED” refers to lights that use light-emitting diodes as their source of illumination. For the most advanced grow lights to date, these produce a wide spectrum of wavelengths while emitting very little heat.

Additionally, they are energy-efficient and can be modified to provide the exact hue light your plant need. They also don’t consume a lot of electricity. All of my grow lights are LED, and I couldn’t be happier with them.

4. HID grow lights

For a variety of reasons, high-intensity discharge (HID) lights have become a popular form of grow light. Most commercial growers use them because they produce more light than any other bulb and mimic the sun better than any other bulb. As a hobbyist, you probably don’t need these.

Bright light is produced by the chemical reaction that occurs when electricity travels from one electrode to the next in a HID. Metal Halide and High Pressure Sodium are the two most common forms. Both emit light, however the former emits blue and the latter emits yellow.

What color grow lights do houseplants grow best in?

The numerous sorts of bulbs have already been discussed, so now let’s talk about the various hues of light they produce. Most likely, you’ve noticed that some horticultural lights are purple, while others resemble ordinary household bulbs.

Cool 400nm–500nm

Cool colors include violet, blue, and green. In most cases, violet light is only useful when paired with red and blue light. Color, taste, and fragrance can all be enhanced by using it.

Blue light, which is absorbed by chlorophyll, is critical to plant growth since it is a major component of photosynthesis. The majority of green light is reflected back by plants, making it less effective for plants to utilise (which is why plants are green). There must be some green light for your plant to grow properly.

Warm 580nm-700nm

Red, orange, and yellow make up the warm end of the color spectrum. The combination of red and blue light is essential for plant growth. As a result, red light encourages greater plant growth and even encourages flowering.

In addition to promoting germination and regulating flowering, far-red light can also be used as a signal. Even while orange and yellow aren’t quite as effective, they’re still critical to the growth process overall.

The best of both worlds: Full spectrum

Growing your plants under full-spectrum grow lights is the most similar to having them exposed to natural sunshine. Even the invisible ultraviolet and infrared radiation emitted by the sun is visible to the naked eye.

Why should I care about other wavelengths if blue and red light are the most crucial for plant growth? You are weakening your plant and possibly stifling its growth if you exclusively use red and blue light.

A wide variety of wavelengths and intensities is required for plant growth, which is why grow lights should emulate natural sunshine as closely as possible. So it’s ideal to use a full-spectrum grow light to get as close as possible to the natural spectrum.

Grow bulbs vs grow light fixtures

The most convenient and economical solution is to use grow light bulbs. It’s as simple as replacing the bulb in an old light or fixture with a specific grow bulb. All types of light bulbs, including incandescent, fluorescent, and LED, are compatible with this.

When used in a communal space like the living room, this LED bulb is ideal for growing indoor plants. It’s easy to install and emits the correct wavelengths for your plant while yet being pleasant to look at. However, if you only have one bulb, you won’t be able to light several plants.

If you have a lot of houseplants, a lighting fixture is a better choice, although they are more expensive than a bulb. All of your plants will receive the right amount of light thanks to the special features of grow light fixtures. They don’t produce heat and have a wider color spectrum than standard incandescent bulbs.

Lighting fixtures are pricey and take up a lot of room, which is why I don’t use them. LED strips are a less expensive alternative to traditional lighting fixtures. Affordable, easy to set up, and capable of illuminating a wide range of plants, these LED Grow Light Strips from Mosthink are a great option.

How to set up single grow light bulbs

When it comes to installing grow lights in your house, the options are nearly limitless. Seed beginning or growing smaller foods like lettuce benefit greatly from a functional approach. Or, like I do with my greenhouse cabinet and hanging bulbs, you might try for a combination of form and utility.

Before we go any further, let’s have a look at the benefits of using individual grow lights. Using single bulbs is an option if you only have a few plants to illuminate. My plants in the darkest parts of the house benefit from a few hanging from the ceiling. A long line and small cup hooks put into the ceiling are all I need to hang these.

Make sure your grow lights are set to timers, as plants shouldn’t be exposed to light 24 hours a day. To avoid forgetting to switch off the grow lights, I use these smart plugs to set a timetable. 8 hours a day is the maximum time I leave them on, and they don’t have brightness dimming capabilities.

How to set up grow lights on shelving or in a cabinet

After that, we’ll talk about how to place grow lights on shelves or in a cabinet, respectively. Select a solid shelf or cabinet for your books. Using a wire shelving unit is a terrific option because it’s easy to find at your local hardware shop, it’s reasonably priced, and it’s simple to clean.

Fabrikor, an Ikea glass cabinet, is what I ultimately chose. My entire Ikea glass cabinet assembly post is available here. With its glass windows and glass shelves, it’s a lovely decorative cabinet that lets in plenty of natural light. Ikea has a wide variety of reasonably priced greenhouse cabinet solutions.

It is time to choose the location of your grow lights. A longer grow light is likely to be required for a larger shelf, such as a wire shelving unit. Fluorescent tubes are an excellent choice because they consume 75% less energy and last 10 times longer than incandescent bulbs. S-hooks can be used to attach these to a shelving unit.

The shelf or the grow lights will have to be raised as your plants get taller. I used double-sided tape to affix these LED strips to the top of my greenhouse cabinet because they don’t require fasteners. I can grow my plants near to them because they don’t emit any heat.

Your grow lights should be set to run on a timer. In my greenhouse cabinet, I utilize LED strips with timers of 2, 4, and 8 hours. I set it to turn on for 8 hours at full brightness and then turn it off. In the end, it worked best for my plants after a lot of experimentation.

How close should grow lights be to houseplants?

In order to simulate the sun’s rays, grow lights should be hung from the ceiling. Putting grow lights at an angle could cause uneven lighting. The plant’s growth will be tilted if the light doesn’t reach the complete surface area.

Your plants should be at least two feet away from incandescent grow lights because they produce a lot of heat and can harm the foliage. As your plant grows, make careful to adjust the height of the grow light to keep it at least one foot away from your plants.

Because LED lights produce so little heat, houseplants can grow up to six inches away from them without fear of burning. In such places as shelving or greenhouse cabinets, LED lights fit perfectly. To eliminate any uncertainty, I only use LED lights in my home.

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How long should I leave grow lights on for?

The length of time the grow lights are left on and their wattage are equally important as proximity to the plant. In the presence of light, plants are hard at work converting carbon dioxide into glucose. Consequently, if you overexpose your houseplants to the sun, you risk damaging their foliage, preventing them from blossoming, and drying them out.

Plants, on average, require at least eight hours of darkness each day. It is during the hours of darkness that a plant draws on its reserves of energy to expand and bloom.

Flowering plants, on the other hand, may require as much as 12 hours of direct sunlight every day. Consistency is most important to plants. Your plants will thrive if you use a timer on your grow lights to provide them a regular light cycle.

What I do with my grow lights…

Depending on the plants you have and the grow lights you employ, this becomes more of an art than a science. How did I go about figuring this out? Here’s how:

  • To begin, all of my lighting is powered by LEDs, so there’s no guesswork involved and no risk of overheating or causing burns.
  • As a second step, I leave the lights on for eight hours a day at their maximum intensity.
  • My plants are first set back at least two feet and then brought closer as I see how they respond to the light. To avoid burning out your plants, you can start with low-intensity lights and move them closer to the plants as you see fit.

Stick with what works best for your plants and your location! Extra light will make your plants thrive, allowing you to lengthen the growing season and improve the health of your houseplants.

Recap: Grow lights I’ve personally used

Here are some of the grow lights I’m currently utilizing, either hanging from the ceiling or tucked away in a cupboard. Before I bought my greenhouse cabinet, I utilized the strip grow lights on DIY open plant shelf.

  • LED Grow Light Strips by Mosthink
  • Led Grow Light Bulbs, 9 Watts, Full Spectrum, from GE
  • An LED Grow Light Strip by Sondiko

Final Words

There are times when we need to rely on technology created by humans and machines. You now know when to use a greenhouse growth light, thanks to this post.

You’ll grow as a gardener if you do things correctly and always adhere to your plants’ needs throughout time.