CFL lights are the “Tom Cruise” of grow lights: ubiquitous, efficient and perfect for short spaces (up to 4’). Another Tom Cruise-like attribute is that they are considered the ideal candidate to take up the “Mission Impossible” of growing in confined spaces.

In the old days growing marijuana under fluorescent (CFL) grow lights was pretty useless as they had low output for a large size. However, the new CFL (compact fluorescent lights) grow lights that between them cover the full visible light spectrum have made them a viable alternative.

But what exactly are CFLs?

CFL Pros and Cons

Pros

They can be found anywhere : CFLs are obtainable in every hardware and grocery store ( WalMart, Sears etc.). There are also huge offers to be found on Amazon and Alibaba;

: CFLs are obtainable in every hardware and grocery store ( There are also huge offers to be found on and Cheap as chips;

Ideal solution for your makeshift PC tower grow box, cupboards and similarly confined spaces;

They run at considerably cooler temperatures than traditional light fixtures. That makes them considerably safer due to lower fire hazard;

Their chiller temperatures also mean that they do not need too much external cooling to stay at normal levels.

Cons

Not particularly strong. HID light fixtures are considerably more powerful, so consider these if you are after bigger grows;

Unsuitable for larger grows.

People who should go for CFLs

People who want to grow a plant or two for personal use;

People who have turned their obsolete PC tower or their grandma’s commode into a grow room;

People who want to try growing a plant but don’t want to spend much.

A little bit of science

Wattage and the Kelvin Scale

Warm white bulbs offer the red-yellow spectrum of light, which is ideal for the flowering stage.

offer the red-yellow spectrum of light, which is ideal for the flowering stage. Cool white bulbs produce more blue spectrum light and are good for the vegetative state.

Vegetative Stage - 5000K / 6500K

Flowering Stage - 2700K

Some Great CFL Models

Agrobrite T5 4' 4-Tube Fixture - EnviroGro

Specs

High efficiency specular aluminum for maximum reflectivity;

Can be hanged in three ways: overhead, vertical or horizontal;

10' grounded power cord;

Includes 4 fluorescent 6400K, T5 tubes, that make this fixture ideal for the flowering stage of your plants;

5-year Ballast Warranty, 1 Year on material and workmanship.

Apollo Horticulture 5-Pack of 2' T5 Bulbs - 2700k and 6400k

Specs

Package Includes 5x T5 Light Bulbs of 24W Each;

Size: 23.5” x 4.6” x 2.6”

Color Temperature - 2700 K;

Lumen - 2,200lm;

Dimensions: Length - 22.12" / Diameter - .62".

Dayspot 26W, 6400K Bulb - Hydrofarm

Specs

26W – 6400K bulb, equivalent to a 130W incandescent lamp;

Lumens: 1600lm;

Lifetime: 10.000 hours;

Size: 6 x 2.5 x 2.5”.

Sun Blaster 26W, 2700K Bulb – Future Harvest

Specs

26W – 2700K bulb, equivalent to a 100W incandescent lamp;

Lumens: 1700lm;

Lifetime: 10.000 hours;

Size: 2 x 1.2 x 0.3”.

How to Use CFLs for Cannabis Growing

The Basics

Reflective Material

Foylon

Mylar

Matte white paint

Panda plastic

Orca Grow Films

Supplies

Things to take into account

CFLs’ light penetration is poor, so, many smaller CFLs are more effective than a few big CFLs . Their light can be spread more easily (although you should cover your grow space with reflective material beforehand). 4 x 40W CFLs (160W) will get bigger yields than 1 x 200W CFL.

. Their light can be spread more easily (although you should cover your grow space with reflective material beforehand). 4 x 40W CFLs (160W) will get bigger yields than 1 x 200W CFL. CFL bulbs under 40W are usually a waste of money. On the contrary, 40W+ CFLs are ideal for small scale growing (up to 250W).

At this scale, power is more important than Ideally, you’ll want to combine the two (and frankly, that is not too difficult to do). Getting more juice should be your top priority. However, learning one or two things about spectrum along the way can’t hurt, so we will expand upon this subject in the following parts.

Set Up

Closet/Drawer

PC Tower

Grow Tent

Seedling

Germinate your seeds and plant them, or just plant your clones;

your seeds and plant them, or just plant your clones; At this stage, your plants should follow an 18/6 light cycle (that means 18 hours of light, followed by 6 hours of darkness). You probably do not want to do that yourself so get a timer for your CFLs;

(that means 18 hours of light, followed by 6 hours of darkness). You probably do not want to do that yourself so get a timer for your CFLs; Water your plants adequately (DON’T water them too much) and watch them reach the vegging stage.

(DON’T water them too much) and watch them reach the vegging stage. Pro Tip: CFLs are awesome for the first weeks of life of a grow, especially seedlings. Regardless of their setup, many experienced growers prefer to use CFL in the first few weeks, so that they can reap the maximum rewards of CFLs.

Vegging

Water it regularly (do not DROWN it);

Adjust your CFLs so they are within 4" of plants (try not to burn them though). The rule is: if it’s too hot for your hand, it’s too hot for your plant !

(try not to burn them though). The rule is: ! Give nutrients (but not too many of them);

(but not too many of them); Train your plants to use as much space as possible . You can find extensive tutorials here;

. You can find extensive tutorials here; Again: don’t overwater or overfeed your plants;

Don’t panic! – most plant problems are easy to fix.

Tips for efficient CFL vegging in a nutshell

Plant Training;

Adjust CFLs Regularly (daily if possible);

(daily if possible); Keep CFLs Close - 4" away from the top of your plants should do it ( remember the hand/plant theorem!) . Try to manage your space so that all parts of the plant are within 8-10” of a CFL bulb;

- 4" away from the top of your plants should do it ( . Try to manage your space so that all parts of the plant are within 8-10” of a CFL bulb; No part of your plant deserves to be in the shadows. Be sure that light is distributed equally;

Try not to move your plant around a lot;

More Watts=More Light=Better Results.

Flowering

Give your buds all the light you can – CFLs can work wonders at this point. Just keep them as close to your buds as possible (without burning them) and watch your plant yield like crazy;

CFLs can work wonders at this point. Just keep them as close to your buds as possible (without burning them) and watch your plant yield like crazy; Keep the temperature at adequate levels – If you read our tutorials, you probably know that temperature control is one of the cornerstones of proper growing. However, the flowering stage requires a bit more attention. Be a little more careful and, if possible, have a small fan blow gently on top of them.

If you read our tutorials, you probably know that temperature control is one of the cornerstones of proper growing. However, the flowering stage requires a bit more attention. Be a little more careful and, if possible, have a small fan blow gently on top of them. Training is over – This is not the right time to train your plants. Generally, you should do that in the vegetative period.

CFL Compared to Other Light Types

CFL v HID Lights (HPS, MH)

CFL v HID in a nutshell

In both cases, you will need some kind of ventilation for your grow room. It is worth mentioning, however, that fluorescent lights will make do with a simple 70CFM fan ;

; HIDs are more powerful but take up more space, so they are not as versatile as CFLs;

Although they are not as hot as HIDs, CFLs are not designed for gardening, meaning that they might cause unexpected problems;

Many growers use them in conjunction to improve their results.

CFL v LED Lights

CFL v LED Lights in a Nutshell

LEDs are a newer piece of technology . As such, they are more efficient and they tend to get better yields for the same amount of electricity;

. As such, they are more efficient and they tend to get better yields for the same amount of electricity; LEDs do not require constant re-adjustment like CFL bulbs;

HPS lights run blazingly hot. CFLs runs moderately warm. A good quality LED with built-in heat sinks, will run cooler even than that ;

lights run blazingly hot. runs moderately warm. ; LEDs need quite a lot of overhead space, so CFLs still remain a better option for shorter grow rooms . LED grow lights must be kept at 12-18" above the tops of plants. CFLs can make do with 4”;

. LED grow lights must be kept at 12-18" above the tops of plants. CFLs can make do with 4”; LEDs will last about 8 times more than CFLs (that amounts to 50,000 hours of use) before they need replacement.

Shopping List and Costs

CFL Grow Lights (obviously);

A grow room/space (2’x2’x4’ and above);

Electrical timer;

Proper Reflective Material (for your grow space);

A growing medium of your choice;

Proper nutrients;

pH Test Kit.

40W CFLs for vegging (daylight) $35

42W CFLs for flowering (soft white) $45

Sockets, Reflectors & Adapters $45

As you probably know by surfing the internet and this website, MH ), LED etc., are competing for a place in your grow room and every one of them has an ace up its sleeve. CFL stands for (Compact Fluorescent Light). Chances are that you have already come across a forum debate that outlines the pros and cons of each lighting type. We too are going to attempt a comparison between the different lighting options, but for now, let’s just focus exclusively on the CFLs.Like everything else in marijuana growing, it all comes down to your personal needs and preferences. There is no one stopping you from installing an HPS lamp in a 2’x2’x4’ closet (good luck with that!), but this is the consensus among growers from all over the world., if you are looking for massive yields and a more automated growing setup, steer clear of CFLs. The rule of thumb here is that, you are better off with some other type of light. We have a whole section for you to choose what suits your needs best!There are a lot of variables to consider when choosing grow lights. Grow light science can confuse you a little bit at first, but after a while, you should know what you are looking for.. If you believe that you are fairly knowledgeable about the facts below, you can skip this part and go straight to the shopping list. The rest of you, take a deep breath and follow us to the exciting world of lighting science.Your objective when buying CFLs should be to purchase thethat is the highest possible for your grow area. Usually, more wattage means more power, which in turn means more light, and thus, more food for your plants. If you want to determine the suitability of the lights, you will want to also check theto understand their output.Generally,. So if a standard CFL bulb gives off 2,500 lumens, you'd need 4 or more of those, until you reach the desirable levels.. Four 42W CFLs use 168W and emit 10,800 lumens. More powerful CFL lamps maintain a similar Watt/lumens ratio, so you get the picture.Remember, CFLs are more suitable for small-scale operations.But that’s not all; this is where thecomes to play. For those who skipped our lighting tutorial (shame!),. Marijuana plants love red and blue light, so you are basically looking for bulbs that are as close to that as possible. Interestingly enough, HPS lamps emit light that is mostly in the yellow spectrum (meaning that most of it goes to waste). And this is where the CFLs shine (pun intended):. As we have repeatedly written in this website, different growth stages require different light spectrums.Bulbs on the lower side of the Kelvin scale, like the 2700K, are more suitable for the later stages of plant growth, while 6500K ones are better for vegging. If you use the in-between spectrums, then you get a nice and balanced result by modifying the rest of your bulbs accordingly. Every indoor growing light ever. The sun also produces green, and orange rays, but cannabis plants do not use them.Bulbs that are more blue are called "Cool white" or "Daylight" colored and are listed with a Kelvin of 5000K / 6500K.when your plants naturally need more sunlight.Bulbs with a more yellow/red tint are listed as "soft white" colored with a Kelvin of 2700K.when your plant thinks that winter is coming.Here are some of our favorite CFL models and their specs. Although there is no reason to be overly picky with your bulbs when growing with CFLs,This model comes two sizes: 2’ (23” x 13.5” x 3”) and 4’ (48.5” x 15.5” x 4.2”) and five patterns (2, 4, 6, 8, 12 tubes), offering you a wide range of customization.These tubes come(bloom)(growth), so you can pick whichever suits your needs, according to your plants’ stage of development.This CFL spiral bulb provides you with all the light you need, while at the same time reducing energy costs.The SunBlaster 26W CFL light bulb was designed with growers in mind. They will fit in almost any light fixture and they their output is equivalent to that of a 100W incandescent light bulb. Thespectrum, means that they are aIf you still believe that CFLs are what you need, then we are assuming that you have a limited space to work with. Therefore, the following tutorial will be focused on growing. In reality, this is a short tutorial on growing small with CFLs, but there are some useful lessons along the way.Go on, we'll be waiting.Back already? Assuming you have done your homework (or at least have grown -basically any- plant before), you know that houseplants need three things in order to survive, in this order. Marijuana plants go throughthat are universally acknowledged among cannabis growers:, and. All these transitional phases are determined by distinct patterns in the lighting cycle In reality, there are many transitional periods that are also important,(at least for now). You can find more on marijuana grow phases here. Cannabis plants have no pre-determined sex. Therefore, you should make sure that the conditions you provide promote the development ofplants (the ones who provide you with smokable buds). More on that here In order to make the maximum use of the light from your CFLs and reduce light leaks,These will distribute the lighting more evenly across your plant, ensuring that no corner will be left in the dark. Even the best of grow lights can not penetrate the whole of the plant on its own, so some reflection is needed. Mainly, you’ll be looking at these options:Durable, easy to maintain, 90-95% reflectionPopular, cheaper, 92-97% reflection (2mm version)Cheap, can be found anywhere, 80% reflectionEasy to clean, perfect short-term solution, 80% reflectionMold resistant, easy to clean, expensive, 95% reflectionAll of these options are readily available online or at home improvement stores. However, consider opting for the easy solution, which definitely a grow tent . It comes as pre-built setup and it will be already insulated and coated with reflective material. If you are impatient or not quite the handyman, check out the offers by Dealzer and Superlcoset . Grow tents are(contrary to grow boxes) andHere is where things get interesting.. Although you can play around with the lighting, the optimal CFL arrangement would be. You are welcome to experiment, but this is the foolproof approach!We started this article by stating that CFLs are the masters of growing in confined spaces. So, here is a list of grow rooms that CFL bulbs would thrive in.Any old furniture will do if you have the patience and skill to turn it into an adequate grow room. Just be sure to properly insulate it. More info and how-to’s here As the era of tower PCs is drawing to a close, it would be wise to find a new use for your old friend, with whom you spent hours of playing Quake 3.(more info on how to turn one into a grow room here ).Cheap, flexible and reliable, grow tents are by far the. Check out our friends at Dealzer and SuperCloset for some really cool models! Just be sure to stay around the 2’x4’ range if you want to start small.This is where things start to get serious. Your plant is basically just a baby at this point, so treat it like one! At this point, the plants need more daylight and thereforeorcolored bulbs, that run at 5000-6500K.Remember that plants are growing rapidly at this stage, so give them a bit of leeway so they don’t grow directly into the lamps. A good all-round solution is to train them.. Training is a big part of a successful grow and it we have covered it extensively here at HTG. Here is a list of all the training articles we have presented on this websiteWhen you switch your light schedule from 18/6 to 12/12, your plant will enter the flowering stage, responding to the fewer hours of daylight. This effectively tells your plant that it is time to reproduce because it’s going to die soon. At this point, you should run a check so you can make sure thatAt this point your plants require bulbs with a more yellow/red tint. These are often called "soft white" and are colored with a Kelvin of 2700K.since your plant is getting ready to flower before winter comes.When your plants' buds fully develop, then it's time for harvest. Lighting has nothing to do with harvesting, so for that, you can follow our in-depth guide! Just be patient and cure your buds properly!As we’ve seen above, CFLs are more suited to small growing rooms, so if you don’t have a lot of space, there is no question. CFLs will do the trick, as long as you readjust them every now and then. HIDs are more powerful and generally require less tinkering.LEDs are the latest “it-thing” in growing technology. We have a whole section dedicated to the LEDs pros and cons here in HTG. Let’s see how they fare against CFL lights.When it comes to lighting there is no “best” option. Every case is unique and you should decide based onand not marketing hype. From a purely technological standpoint, however,(and expensive). If you want more information on the subject, you can check out our article about lights. The above simulation was run with just one plant in mind. We wouldn’t advise adding more than two in the same space if growing with CFL. Below,Generally, 150W of CFLs (a default start). Adding more lights will help (up to a point!), but it is ultimately a matter of strain selection. Setup costs may vary according to your location and suppliers. Here is a detailed breakdown of the bulb costs:Electricity costs may vary across states, but on average it is about $0.30/kWh. If you are growing only one plant with an average of 150W, then your monthly electricity costs (should be around $25 (if we assume that the lamps will be on for an average of 18h/day). That’s about $0.80 per day! It is worth mentioning