How to Grow Cannabis Plants with CFL Bulbs?

Growing cannabis is easy, but it can be challenging when you want to set up a nice indoor grow room. You browse online for some recommendations but leave more confused than ever, especially when the cost of purchasing a nice grow light seems like it could burn a hole in your pocket. 

Nah, I’m going to stick to buying buds, you tell yourself and go on about your day. However, it doesn’t have to be that complicated. Look at our forum, for instance. Most growers aren’t spending a lot and are still yielding high-quality marijuana. This is because they know where to look, and have a lot of experience already. 

Remember, problems arise when you make it super complicated. Cannabis has flourished easily in some of the most challenging regions of the world, so growing it at home shouldn’t be too difficult. 

In this article, we are going to help you understand that you don’t need to spend your month’s paycheck on grow lights even if you’re a beginner. You can get started with cheap CFL grow lights that produce decent results for the price you pay for them. Yes, they aren’t as effective as LEDs, but for beginners, they are perfect. 

We will cover various aspects of CFL grow lights, including the right color temperature, the number of CFLs to use, the best training methods, etc, and you should be able to start immediately. 

What are CFL Grow Lights?

CFL stands for compact fluorescent lights, which produce light with a combination of mercury vapor and argon gas. When these gasses are exposed to electrical current, they generate UV light, which is invisible. So, the bulbs use a fluorescent coating within the tube to turn it into visible light. 

CFL bulbs were designed to replace incandescent bulbs, which were known to be not so energy efficient. As a result, CFL bulbs are comparatively much more energy efficient and they also last 10 times longer while generating less heat — perfect qualities for cannabis grow lights. 

Of course, LED lights have taken the cannabis industry by storm and replaced CFLs; the former is way more energy efficient, lasts for years, and produces better light. But that doesn’t mean CFLs no longer belong in cannabis grow rooms. 

CFL grow lights still have a place in many cannabis grow rooms. They are suitable in a few instances, such as:

• You intend to grow only a couple of plants and don’t have a lot of space 
• Growing cannabis is just a hobby and you want to be sure you can do it before diving into it or exploring expensive alternatives
• You’re a beginner
• You want to save as much money as you can 

In such cases, CFLs make sense. However, you should know that CFLs won’t work for you if you expect a yield of more than a few ounces, don’t have time to tend to your plant, or grow anything over 2-3 plants at a time. In such cases, it’s better you go for HIDs or LEDs. 

What are the Advantages of CFL Grow Lights?

CFLs are not usually the first choice unless you are a novice hobby grower, but that doesn’t mean they are not worth checking out. They come with several benefits that make them worth the investment and attention. Here are some reasons why you should consider using CFL lights.

1. Easy Availability 

One of the significant benefits of CFL grow lights is just how easy they are to get your hands on. Remember, these are the same lights that are used in homes, so you can find them in general stores across the world, even in the most remote regions. Sure, some of them may not grow lights per se, but as long as they work, it shouldn’t matter. 

2. Affordability

Since CFL lights are literally a household item, they are super cheap to buy. In fact, you wouldn’t even feel bad if you purchased extras or used them as disposable lights because they are so cheap. So, even if you are growing two plants, you can purchase a set of CFL lights without thinking too much about it. 

3. Energy Efficiency

CFL grow lights are nowhere as energy efficient as LED grow lights, but they are still quite energy efficient. They can easily give HIDs and other grow lights a run for their money since they save electricity while producing bright light. For example, even if you require 800 watts of energy to light our grow lights, you will only spend a couple of dollars every day with CFL lights. 

4. Heat Efficiency 

One of the biggest drawbacks of traditional HID grow lights is that they tend to heat up a lot. This can especially be a problem for smaller gardens, where the plants are in close proximity to the lights and the setup isn’t as elaborate to contain fans or coolers to keep the temps down. 

This is where CFL grow lights offer tremendous benefits. Since CFL grow lights don’t produce a lot of heat, you won’t have to worry about adding additional fans and coolers to the grow room to keep the temperatures down. Your plant will be safe from CFL lights even if you place it 2 inches from the bulb — although you shouldn’t. 

5. Uniform Light Distribution 

Another excellent benefit of CFL grow lights is the light distribution pattern, which is quite uniform. Given the construction of these lights and how they produce light, these CFL bulbs emit light in a uniform manner, minimizing the light hot spots on your plant’s canopy. However, you’d need several lights to achieve this. 

6. Versatile

We have mentioned that CFLs need to be replaced frequently due to their spectrum as a disadvantage below. However, if you’re ready to change the lights according to the growing stages, you’re going to find CFLs amazing in terms of versatility. 

They come in various color temperatures, allowing you to use them for various stages of your plant’s growth. For instance, you can use cool white CFLs during the vegetative stage and switch to warm white bulbs during the flowering stage. While the bluish-white light produced by cool white bulbs will help the plants develop lush foliage, warm white bulbs will encourage more buds and help the plants transition easily from their vegetative stage to the flowering stage. 

What are the Drawbacks of CFL Grow Lights for Cannabis?

Like anything else, CFL grow lights also come with several drawbacks. Here are some of the most common drawbacks of CFL grow lights for cannabis that you should know about. 

1. Frequent Replacement 

CFL grow lights need to be changed during each growth stage, which is not the case with LED grow lights that last the entire lifetime of the plant. This is because CFL grow lights can only produce one spectrum of light, which is not ideal for every growth stage. 

For example, your cannabis plant needs 6500K light during the growth stage and a warmer 2700K light during the flowering stage. These spectrums of light ensure the best plant growth in the respective growth stages.

Similarly, CFL grow lights don’t last very long. Most of them have a life of around 10,000 to 15,000 hours, so you will only get through a couple of seasons before they die on you. But that’s alright; CFL lights are so cheap, you wouldn’t mind replacing them frequently. 

2. Less Powerful

One major drawback of CFL lights is that they are not as powerful as HID or LED grow lights. So, CFL grow lights only work for small cannabis operations with a couple of plants, and you also need to prune and train your plants to maximize their light exposure when using CFL lights. 

3. Low Yield

CFL grow lights are the worst kind of lights if all you are looking for is a massive yield. These lights produce average yield since they produce the bare minimum of light that’s required by your cannabis plant. For extraordinary yields, you should check LED or HID grow lights. 

4. Low Light Intensity

CFLs have low-intensity light compared to high-intensity lights like HPS or LEDs. CFLs emit light in several directions, so the intensity reduces as the distance from the bulb increases. Therefore, it’s pretty challenging for CFLs to penetrate into the canopy of cannabis plants. As a result, the lower branches don’t get as much light as the upper parts of the plant, resulting in less growth and less yields.

Cannabis plants love high-intenisty light, especially when they begin to flower. This is because they need more light to produce thick buds packed with resin. Low intensity light also produces buds but they are not as big as those under high-intensity lights. Also, you may find that the buds aren’t as potent either because the plants don’t have the support to produce strong buds filled with lots of cannabinoids.

In addition, CFLs don’t offer much coverage. If you want to get a good coverage area where all plants get equal light, you’ll have to use multiple bulbs, thereby adding more complexity and costs to the setup. This is why many growers opt for one high-intensity light rather than using several low-intensity CFLs. Yes, CFLs are more energy efficient, but high-intensity lights produce more photons that enhance photosynthetic activity and lead to higher yields. 

Things to Keep in Mind When Using CFL Grow Lights 

CFL grow lights, surprisingly, are easy for you since it’s almost impossible to give your cannabis excess light with these bulbs. LED and HPS lights can easily burn your plants, but that’s not the case with CFLs in most cases. But that doesn’t mean you hang a CFL over your plant and call it a day. You need to keep a few things in mind.

1. Get Enough CFL Lights 

When growing cannabis, if you are only growing a single plant, you should start with 150 watts worth of CFL grow lights — they produce enough light to sustain a single plant. So, for a single plant, a good starting point is to get a couple of 40W daylight CFLs and a couple of 40W soft white CFLs. 

Additionally, try using smaller lights. CFL’s light penetration is poor, so multiple smaller lights are often more effective than a couple of big ones. So, instead of using a single 200W bulb, use smaller 40W bulbs (around 4) that produce the same result as the former but offer much better light penetration. 

If you are using CFL bulbs in a smaller setup, like a space bucket, you should stick to 20 to 30-watt bulbs. And if your plant grows taller than a foot, 40W lights will be enough. Remember, this is just a general guideline and the right CFL setup for your cannabis plant may vary depending on the strain you are growing. 

Here are a few setup examples to get you started:

1. Recommended: 2 x 42 6500K CFLs and 2 x 40W 2700K CFLs
2. A combination of 3 x 23W 6500K CFLs and 3 x 26W 2700K CFLs
3. A combination of 1 x 62W 6500K CFL with 2 x 65W 2700K CFLs

Don’t hesitate to mix and match here until you find a combination and number that works best for your cannabis plant. 

2. Color Spectrum

When you use LED grow lights, you can tweak the color spectrum they produce, which is very handy, but such grow lights are expensive. Unfortunately, CFL grow lights don’t have the same feature, so you have to be mindful of the color temperature of the CFL lights you choose for growing cannabis. 

CFL grow lights come in different color temperatures or spectrums; some are more yellow or orange (warm) others are almost blue (cool), and some are bright white light daylight. 

Honestly, all types of CFLs work for growing cannabis, but it’s always better to go the extra mile and choose CFLs with the right color spectrum based on your plant’s growth stage to ensure the best results. 

For a vegetating cannabis plant, you should stick to cool white CFL lights with a rating of 6500K. These lights produce the right kind of light that cannabis prefers during the vegetative stage, which helps it grow bushy. CFL bulbs with cooler color temperatures emit a light that closely resembles natural sunlight during spring and summer. 

Cannabis plants prefer more blue light at this point. Thus, this spectrum promotes vegetative growth and the plant starts developing leaves, stems, and branches. Do note that you may still have to use some training methods for optimized results. 

On the other hand, if your cannabis plant is flowering, you should choose warmer CFL lights with a temperature of 2700K. They produce a light that mimics autumn sunlight. This spectrum is well suited for the flowering stage of cannabis plants as it encourages bud development and facilitates the transition from growth to flowering.

If you don’t want to think too much, you can simply mix different spectrums of CFL lights; for example, you can use two cool white lights and two warm ones. 

3. Light Optimization

CFL grow lights have excellent light spread but the light penetration isn’t so good. This works as a double-edged sword because a lot of the light produced by the bulbs can be wasted on the surrounding area of the plant. 

So, it is always a good idea to optimize light throw with the help of reflectors. These reflectors help minimize the light loss in your cannabis grow room by redirecting the wasted light back to the plant’s canopy. 

Some of the best reflectors you can use here are flat white paint, panda film, mylar film, aluminum foil, etc. These are cheap solutions that work wonders for reducing light wastage and the result would be a bushier plant that gets light from multiple directions, so even the lower branches can grow well. 

If you are short on space and want an easy route, we recommend using a grow box. These grow boxes are designed with cannabis plants in mind and come with all the attachment points for lights and fans, and in this case, they also include a reflective material on the inside. 

What Kind of Yield Can You Expect from CFL Grow Lights?

In short, you can expect a yield of around 0.25 grams per watt of CFL grow lights. 

This is a general rule, so take it with a grain of salt. Depending on your cannabis plant, its strain, and other environmental factors, you may get a yield that’s more or less than 0.25 grams per watt. Also, this estimation factors in CFL lights true watt, not any equivalent wattage that some companies use to upsell their products. 

So, if you use 150-watt CFL lights to grow cannabis, you can expect a yield of around 37 grams or over an ounce from one cannabis plant. If you want to increase this number, you can try adding more CFL grow lights and train your plants well. 

The importance of training your plant cannot be understated while using CFL lights to grow cannabis. This is going to make the biggest difference. So, you need to spend some energy to ensure your plant gets optimal levels of light penetration from the CFL lights. 

How to Use CFL Lights to Grow Cannabis?

Cannabis is a really vast subject and as such, there are a ton of correct ways to do everything. Using CFL grow lights is no different since there are many ways to use them. But for the sake of simplicity, we’ll list down a guideline that you can use as a starting point for growing cannabis with CFL lights. 

1. Research and Gather Knowledge

Before you start growing cannabis with CFL lights, it is recommended that you gather as much information as you can about your cannabis strain and the best way to grow it. This won’t take more than an hour but you’ll understand exactly how much light your cannabis plants need along with other requirements. 

Essentially, you want to research as much as you can about your plant’s growth stages, its environmental requirements, expected height and width, expected yield, best training methods, common problems it may face, etc.

2. Gather Your Supplies 

The next step is to gather all the supplies that you’ll need for growing your cannabis plant, including CFL lights. Your shopping list should at least consist of seeds, a light-proof growing box (tent, closet, buckets, etc.), CFL lights, a growing medium, a pH meter, nutrients, and an electrical timer. 

3. Prepare Your Grow Space

Once you have everything at hand, you need to start setting it all up. If you’re using a closet to grow cannabis with CFL lights, the process is very easy. You can place your plants under the CFL lights and let them grow — this is a rudimentary setup but there isn’t much you can do in a closet, anyway. 

On the other hand, if you are using a grow tent, you can follow the manufacturer’s recommendations to set it up. Make sure you add the right number of CFL lights that fit in the grow tent along with your container and fans. 

4. Seedling Stage

Once you have everything set up, you can start growing your cannabis, and the first step would be to sprout or germinate the seeds. In this case, it is recommended that you use CFL grow lights on an 18/6 schedule, ie., 18 hours of light and 6 hours of complete darkness. 

To make the entire process easier, attach your CFL grow lights to a timer so you don’t have to constantly worry about switching the lights between on and off. Once the plant has grown a few sets of true leaves, you can transplant it into a container. 

5. Vegetative Stage

Once your cannabis plant starts growing, it is in the vegetative stage, and here is where it will require a lot of light. During the growth stage, your plant will put on a lot of weight so it needs a lot of water, nutrients, and light. 

As for water and nutrients, make sure you give it enough of both but not too much. On the other hand, you need to be careful about the CFL placement. Ideally, your CFL grow lights should be within 4” of the plant at all times, so adjust when required. Don’t let the plant get too close to the light as it can cause burning. 

A good way to check this is by using the hand test. Place your hand just above the canopy of the plant for half a minute; if it feels warm to you, it is warm for your plant, too. If that happens, move the CFL lights up until it no longer feels warm on your hand. 

Since you are using CFL grow lights, you may also have to train your plant to optimize light penetration. CFLs don’t have the best light penetration. If your plant is in its early growth stage, you should start bending (low-stress training) to create a wider canopy. You can also try other training methods on your cannabis plant, but stick to low-stress training for starters, like bending, pruning, ScrOG, etc. 

Once your cannabis plant reaches half the expected final size, you can switch the CFL lighting schedule to 12/12 from 18/6. This will force your cannabis plant to switch to the flowering stage.

6. Flowering Stage

Once your plant has entered its flowering stage, you need to be vigilant and keep an eye on the plant’s growth. In the first couple of weeks, the plant will experience a flowering stretch, so ensure you move the CFL grow lights accordingly. 

At night or during night hours, ensure that your cannabis plant does not get any kind of light — light leaks are a nuisance and can significantly hamper your cannabis plant’s growth. In worst cases, it can even push your cannabis plant to re-vegging. 

Once the buds start developing, make sure you have moved your CFL lights as close as possible to the plant without burning them. Flowering cannabis requires a lot of light, so you must keep the lights closer. Do make sure that the lights don’t heat the plant too much and avoid training your plant at this stage. 

Summary: How to Grow Cannabis Plants with CFL Bulbs?

Exploring cannabis cultivation through CFL grow lights unveils a world of possibilities for beginners and hobbyist growers. Despite the allure of high-tech alternatives, CFLs offer easy accessibility, affordability, and efficiency. While they have limitations in yielding massive quantities, the uniform light distribution, energy efficiency, and minimal heat emission make CFLs a viable option.

Remember, optimizing light distribution, selecting the right spectrum, and employing proper training techniques can unlock the full potential of CFL grow lights in nurturing cannabis plants.