Grow lights are one of the crucial components to growing indoors since you cannot get enough natural light to sustain and produce flowers. There are three primary kinds of grow lights that growers rely on that provide reliable results for growing cannabis flowers: High-Pressure Sodium (HPS), (Ceramic) Metal Halide ((C)MH), and Light Emitting Diodes (LEDs). You can also grow with fluorescent or incandescent but don’t expect great results when growing with cannabis – these bulbs simply do not give off enough useful energy. We’ll talk about when to use a grow light, the differences between these grow lights, how far to hang them, how high your light intensity should be, and what the spectrum should be for each growth stage.
When to use a grow light?
As a cultivation expert, understanding when to use grow lights is essential for successful indoor gardening. Grow lights play a critical role in providing supplemental lighting to plants, especially in environments where natural sunlight is limited or unavailable. Here are some key insights into when and how to use grow lights effectively.
1. Lack of Natural Light:
Grow lights are indispensable in indoor gardening setups where plants do not receive an adequate amount of natural sunlight. This is particularly common during the winter months or in locations with limited sunlight exposure. In such cases, grow lights serve as a reliable source of artificial light to support plant growth and development.
2. Seed Germination and Early Growth:
During the seed germination stage, providing consistent and adequate lighting is crucial for ensuring successful sprouting and early growth. Grow lights can help simulate ideal light conditions, promoting robust seedling development and preventing issues such as elongated stems or leggy growth due to insufficient light.
3. Vegetative Growth Stage:
During the vegetative growth stage, plants require more intense light to support healthy foliage development and robust growth. Grow lights with appropriate spectrum and intensity can stimulate photosynthesis, encourage lush green foliage, and promote strong root growth. Adjusting the duration and intensity of grow light exposure during this stage is essential for optimizing plant growth.
4. Flowering and Fruit Production:
As plants transition to the flowering or fruiting stage, their lighting requirements change. Grow lights with specific spectrums, such as red and blue wavelengths, are commonly used during this stage to promote flowering, fruit set, and overall reproductive development. Properly timed and controlled lighting schedules are critical for maximizing yields and quality during the flowering phase.
5. Supplemental Lighting:
In addition to providing primary light sources, grow lights can also serve as supplemental lighting to complement natural sunlight in outdoor gardening settings. Supplemental lighting can extend the photoperiod, provide consistent light levels during overcast days, or compensate for shaded areas, ensuring uniform plant growth and development.
Conclusion:
In conclusion, knowing when to use grow lights is essential for optimizing plant growth and productivity in indoor gardening environments. Whether for seed germination, vegetative growth, flowering, or supplemental lighting, choosing the right type of grow lights and implementing appropriate lighting schedules are crucial for achieving successful outcomes. By understanding the specific lighting requirements of different plant stages and adjusting grow light usage accordingly, growers can create optimal growing conditions and maximize the potential of their indoor garden.
The difference between these grow lights:
These days, most growers will opt for purchasing HPS or LED fixtures. CMH/MH fixtures remain a distant third to these two, and perhaps unfairly because CMH does indeed provide a full enough spectrum for a full growth cycle, but MH bulbs do not – they are great for the veg stage but not for flowering because the spectrum they produce is mainly blue light. CMH does a great job but for our purposes, we’re going to examine just HPS and LED. Let’s take a look at how they compare.
Whether you decide to use HPS or LED or CMH/MH lights, is up to you. When you do, there are recommendations for light. Let’s take a look at light height according to wattage.
Light Height for HPS/CMH/other HID type lights:
| Watts | Height (inches) |
| 150w | 36” (seedling) / 24” (veg/flower) |
| 250w | 36 – 40” (seedling) / 30 – 36” (veg/flower) |
| 400w | 48” (seedling) / 36 – 42” (veg/flower) |
| 600w | 54” (seedling) / 36 – 42” (veg/flower) |
| 1000w | 60” (seedling) / 48 – 54” (veg/flower) |
Light height for LEDs:
| Growth stage | Height (inches) |
| Seedling | 24 – 30” |
| Veg/flower | 18 – 22” |
What is the ideal spectrum for each stage of growth?
Great question! We have a handy chart to give you the perfect answer. When purchasing your light, consider the light spectrum and which parts of the spectrum your light emphasizes – that will determine if your light is suitable for the various stages of growth. Our goal is to maximize the production of THC and we can do that by providing different “colors” at different stages of growth.
In this graph, you can see that there are two “points” that are higher than the rest. These peaks show that this coloration of light is more needed for photosynthesis and the creation of chlorophyl and sugars plants utilize to develop. Blue light is utilized by plants to build structures, such as leaves and stems; red light is used to build flowers. This graph is ideal and what you’ll want for your light if you want a full spectrum light. If you want to emphasize either blue or red, look for spectrum charts that do just that.
We hope this has been a useful primer for your growing journey! Good luck and come back for more info!
More Information about Light Distance and Light Intensity:
How Far Away Should My Grow Lights Be?
How Far should Seedlings be from Grow Light ?
What’s the Best Grow Light? Unveiling the AeroLight Revolution by Vivosun
What You Need to Know About Grow Lights?
As always if you have any questions you can message our Instagram or Facebook and we’ll be glad to help you out! We’re happy you’re on this journey and we want to help in any way we can.
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