How to Grow Weed With CFLs
by Nebula Haze (with many cannabis CFL picture contributions by the CFL King joeblow)
Table of Contents
When growing cannabis indoors, grow space for a garden is often limited! This is where CFL grow lights shine in every sense of the word! If you have a very small grow space, CFLs may be just what you’re looking for.
Today, I’d like to share some extra tips and hints for growing cannabis with the super-cheap grow lights which also happen to fit in extremely small spaces… CFLs!
Don’t have much space to grow indoors? Try CFLs!
Fat cannabis buds grown under CFL grow lights – picture by joe blow
What are CFLs?
CFL stands for “compact fluorescent light” and even though these lights can be found at any hardware or grocery store, they actually give off a really great light spectrum for growing marijuana.
Benefits of growing with CFLs
Cheap to get started
Easy to find in grocery and home improvement stores
Suitable for very small or short grow spaces, like the inside of a cupboard, small grow tent, or even a 5-gallon bucket
CFLs are a great option if you…
Are growing in a very small or short space
Plan to grow only 1 plant
Want to harvest about 1-3 ounces of bud
Are willing to check on your cannabis every day
Want to ‘try out’ growing cannabis without investing much
CFLs are not well suited for growers who…
Want to harvest more than a few ounces each grow
Can’t tend plants regularly
Have lots of space; if you have at least 5 feet of height in your grow space, I recommend upgrading to a more efficient grow light.
- Average Yields: 1-2 ounces (harvest every 4 months so about 1/4 -1/2 oz/month)
- Recommended 1-2 plants
- Grow space is 2’x2’x4’ or larger
- Setup Cost if No Fan or Carbon Filter: $386
- Setup Cost w/ Fan & Carbon Filter: $471.00
- Estimated Monthly Electricity Cost: $59/month
- Total Cost for Entire First 4-Month Grow (Setup + Electricity): $707 ($353-707/ounce)
- Total Cost for Second Grow (Nutrients + Electricity): $266 ($133-266/ounce)
Learn more about CFLs vs other popular types of cannabis grow lights
Here’s a picture of one of my very first grows with CFLs.
How to Grow Cannabis with CFLs: Step-By-Step Growing Tutorial
Hint: There are tons of ways to get the most out of your indoor grow space. In the past, we’ve covered how to train your cannabis plants to grow into a short “table” shape that is more efficient under grow lights than letting the cannabis plant grow without interference. These cannabis training techniques are especially well suited to growing cannabis with CFL grow lights.
Step 1: Understand the Basics of Growing Cannabis
You may not want to hear it, but before you do anything related to growing cannabis, you need to make sure you understand the basics of growing cannabis. Skipping this step will cause you all kinds of unnecessary heartbreak!
Today I will walk you through the steps of growing cannabis with CFLs, but you’ll get more from this guide if you at least understand the life cycle of a cannabis plant. Taking 20 minutes to read the basics tutorial will answer 95% of the most common cannabis growing questions new growers have. Plus, having a primer will make the learning experience smoother and more fun!
What Do I Need to Understand?
Basically, you need to understand that cannabis plants go from seedling > vegetative stage > flowering stage > harvest. Your job is to give the plant light, water and nutrients, just like any other plant. In the vegetative stage the plant grows only stems and leaves (vegetative growth) while it gets bigger. In the flowering stage, the plant eventually stops growing new stems and leaves and starts growing buds. Only female cannabis plants make buds, while male plants make pollen sacs and need to be thrown away immediately. When buds are “ripe” it’s time for harvest.
If you feel confused by a lot of that, please take a few minutes to learn the basics of growing cannabis before you proceed to the next step!
Step 2: Get Your Supplies
You will need light (CFLs), a place to grow, nutrients and a few other supplies to get started growing cannabis with CFLs.
Basically you need…
- Seeds or clones
- A light-proof place to grow (closet, grow tent, etc)
- CFLs (How many CFLs should I get for each plant?)
- Growing Medium (soil, coco coir, hydro)
- pH Test Kit or Pen
- Electrical Timer
How many and what size CFL grow lights should you get to grow cannabis?
Step 3: Set Up Your Grow Space
Now it’s time to get set up!
Examples of Great Spots to Use CFLs
You can literally put your plants in a closet under your CFLs and go. Although it’s not the best setup, that’s actually what I did for my first grow (see pic!). I did run into problems with heat and ventilation, plus I can’t believe I started growing on a carpet without even putting down a tarp or blanket! But it was a cheap and simple way to get started!
Don’t do what I did; never grow on carpet! Always put something down to catch spills!
Soon after I started growing, I upgraded my growing environment by getting a grow tent. If you want to start out with a turn-key grow space without any work setting up, you might want a grow tent. You can buy a small grow tent that’s perfect for growing cannabis with CFLs! A 2’x2’x4′ grow tent is great for CFLs and will easily fit in the back of your closet. A bigger 2’x4’x5′ grow tent is also be a good starting tent size that can be upgraded with bigger grow lights later.
DIY Grow Box, Cabinet or Dresser
Lots of growers will also build their own grow space, and this can be a good choice especially if you take time to make reflective walls and a way to exhaust heat.
Some growers will include both a vegetative and flowering section, or they might dedicate the whole box to one grow.
These small DIY buckets work well with CFLs.
Many new growers already have an idea of where they might grow their plants!
Step 4: Start Your Plants!
Now it’s time to put real plants into the grow space you have created!
- Sprout your seeds (learn how to get seeds and germinate them). Some lucky growers also have access to clones.
- Put your timer on an 18-6 schedule so lights are on for 18 hours a day, with a 6 hour dark period. You can set the schedule however you want so it’s most convenient for you. I usually put the dark period during the hottest part of the day to help keep the temperature comfortable for the plant. Learn more about cannabis light schedules.
Set an electrical timer on an 18/6 schedule, then plug in your CFL grow lights
Right after your seeds have germinated, cannabis plants grow just like a normal houseplant. Just give your plants basic care and watch them grow. In the vegetative stage, cannabis really does grow like a weed!
Don’t worry, there’s more specific info below!
Once your plants get to this size, they are officially in the vegetative stage and should be transplanted into bigger containers before they start getting rootbound.
Step 5: Vegetative Stage
The vegetative stage starts as soon as your young cannabis plant starts growing real leaves. At this point, your plant is only making stems and leaves. It grows just like most houseplants at this stage, so your main job is just to provide water, light and nutrients.
- Water your plants regularly, but not too often
- Regularly adjust CFL bulbs so they are within 4″ of plants but not burning them.
- Give nutrients (but don’t go overboard!) and check pH
- React quickly to any plant problems – most are really easy to fix!
- Train your plants to grow flat and wide
A good way to check if a CFL is too close to the plant is to use the “hand test.” Put your hand where the plant is and leave it there for 30 seconds. If it’s too hot for you it’s too hot for your plants and the CFL needs to be moved further away! Plants can grow a lot in a day, so make sure to give yourself some “breathing room” so your plants don’t grow into the bulbs and burn themselves!
Even if you choose not to train your plants, keeping your CFLs close will dramatically increase your yields compared to keeping them further away!
Keep CFLs Close So the Whole Plant Gets Direct Light!
The plant above has been untrained and has grown into the natural “Christmas Tree” shape of cannabis plants. But that’s not the best way to get bigger yields with CFLs.
Besides basic plant care, the best way you can increase cannabis yields under CFLs in the vegetative stage is to train your plants to grow short and wide so they’re best able to best take advantage of the CFL’s great light spectrum in the flowering stage. Plant training will dramatically increase your yields!
While you don’t have to do training to get to harvest, plant training is actually really easy and will reward you greatly!
For biggest yields with CFLs, train plants to grow short and flat using plant training!
It’s a good idea to start training when the plant is young, since new stems are flexible and easy to bend (LST). If you start early, you can train your plant to grow flat and wide under your CFL grow lights with only gentle bending and tying down.
Here’s an example from above of LST (bending) plus tying down to keep a plant short:
Think about bending any tall stems down and away from the center of the plant. You’re trying to make the top of the plants flat so all the buds are an equal distance from the CFL grow lights. Each bud gets access to lots of light, and will grow bigger as a result!
Twisty ties are a convenient way to tie down stems after bending them, but you can use just about anything to tie down plants except for things like string, which are sharp and can cut into the plant over time.
Plant twisty ties can easily hook around a cannabis stem, while the other side can be hooked to almost anything (like the pot)
Start training when your plants are still young
As your plant grows, be aware of the height. For any stems that are taller than the rest, gently bend them down and away from the center of the plant until they’re at the same level as the others, securing them down with twisty ties, like this:
As the plant grows, continue bending tall stems down and away. As time goes on, you’ll end up with a flat, tabletop shape like this:
Here’s a sneak peak at those cannabis plants after they start making buds – the tabletop shape helps buds get access to the most energy from your CFL grow lights, resulting in chunkier buds and bigger yields with CFLs. This is why we train!
These cannabis plants were trained to grow flat under CFL grow lights by joe blow
This was just a quick walkthrough of marijuana plant training, but you can learn step-by-step how to make cannabis plants grow flat and wide using our LST tutorial!
Vegetative Stage Tactics to Yield More with CFLs
Plant Training – Don’t skip at least basic plant training since it’s extra important for getting good yields with CFLs!
Adjust CFLs Regularly – You want to adjust your CFLs around your plants as they grow, so make it easier on yourself by setting up your CFLs so they can easily be adjusted in your grow space. Keep in mind that CFL adjustment can be a daily task!
Keep CFLs Close – CFLs should be kept 4″ away from the tops of your plants as long as it’s not too hot (use the hand test). If possible, try to arrange CFLs so all parts of the plant are within 8-10” of a CFL bulb.
Avoid Shadowy Areas – If you see a “shadowy” area on the plant, it means you need another bulb there, or need to use bending (LST) to rearrange the shape of the plant so all parts are getting direct light.
Don’t Move Plants – Try to avoid moving the plants. With CFLs you want to train the plant to grow around the lights which is difficult if the plants move every day. If hand-watering your plant, set up the grow space so you can remove runoff water without having to move the plants.
More Light = Better Results with CFLs. In fact you pretty much can’t really give your plant too much light when growing with CFLs (this isn’t true for all grow lights).
Step 6: Flowering Stage
In order to switch to the flowering stage you need to switch your CFLs to a 12/12 light schedule using a timer. This means that the plants should get 12 hours of light and 12 hours of dark each day. It’s really important to make sure the plant doesn’t get any light during the dark period. Light leaks cause problems! Your grow space needs to be completely light proof in the flowering stage.
About 2 weeks after the switch to 12/12, your plant will start making flowers. If it’s a female plant it will start making buds, but if it’s a male plant it will start making pollen sacs which growers don’t want. It’s important to remove male plants from the grow space right away because they can pollinate your female plant and give you seedy buds. Learn more about male and female cannabis plants.
To get the biggest yields, keep your CFLs as close to your buds as possible (without burning them!)
You will thank yourself for training your cannabis plants when you see what happens to all the buds close to the CFL grow lights in the flowering stage!
Here’s a closeup of those big cannabis buds
Big cannabis buds grown under CFLs from seed – pictures by joe blow
Flowering Stage Tactics to Yield More with CFLs
Give Buds Intense Light – In the flowering stage, make sure that buds get direct access to intense light & keep CFLs as close to buds as possible without burning them (this will dramatically increase yields with CFLs). Pay close attention to making sure bulbs are close but not too close in the flowering stage.
This plant was grown under CFLs, notice how all the buds are about the same height – this helps increase yields with CFLs and gives you many large colas!
Step 7: Harvest Plants When Buds Are Ready
When plants are mature, it’s time to harvest!
Start Growing with CFLs Today!
Cannabis CFL Grow Supply Checklist
CFL Grow Lights
When it comes to CFLs and cannabis you basically can’t give your plant too much light. With more powerful types of grow lights (like HPS or LEDs) you can light-burn your plants even in cool temperatures, like a sunburn. But with CFLs it’s almost incredibly difficult to give too much light so your main job is to get as many bulbs as you can as close to the plants as possible (without burning your plants from heat).
Note: Don’t get CFLs confused with old-fashioned incandescent light bulbs!
CFLs that are in the 40-42 watt range are great for growing marijuana, and also make great seedling, clone and/or supplemental lighting
How Many CFLs Do You Need To Grow Marijuana?
Follow these principles with CFLs to get great yields every time:
1.) Start with about 150W worth of CFLs, which is enough light for one small plant
- Total of 150W Per Plant to Start
- Example Setup:2 x 40W ‘daylight’ CFLs + 2 x 42W ‘soft white’ CFLs
2.) Smaller bulbs = better results
Because the penetration of CFLs is poor, many smaller CFLs is more effective than a few big CFLs because they can be spread in an array around the plant.
For example, 4 x 40W CFLs (at 160 watts total) will usually get bigger yields than a cannabis plant grown under 1 x 200W CFL, even though the smaller bulbs use less electricity in total.
For tiny plants in a small setup like a space bucket you want 20-30W CFLs. If you plan to grow your plant up to a foot tall, you may want to use 40W CFLs and bigger since the smaller ones won’t have enough penetration to reach the bottom of your plant. 40W-sized CFLs are a great combination of power and penetration when it comes to growing cannabis with CFLs.
3.) Color Spectrum – Not That Important
There are bulbs with different CFL color spectrums and it’s generally recommended to get “daylight” (6500k) CFLs for the cannabis vegetative and “soft white” (2700k) CFLs for the flowering stage. Each color spectrum has a small impact on how the plant grows (ex: 6500k encourages slightly more squat growth).
But the truth is that total power, or total wattage of your CFLs, is much more important than spectrum with CFL grow lights! At least when it comes to your yields. CFLs in any spectrum will do the job! If you do want to get all of one color spectrum, get all “soft white” (2700k) CFLs, or whatever is cheap and can give you the most watts for your money. We will go into much greater detail about CFL color spectrum below, but the main takeaway is that watts is far more important than spectrum!
4.) Total Yields to Expect from CFLs (0.25g/watt)
This will help you estimate how much yields to expect from your CFL grow, but you need to remember to take this with a grain of salt. A very general rule of thumb is to expect about 0.25g/watt of CFL light if you use plant training and don’t run into major plant problems. This is counting CFL true watts, not any type of “equivalent” watts. Some CFL growers definitely get bigger yields than that with CFLs, up to about 0.5g/watt for the pros, but 0.25g/watt is what you should expect as an upper limit for a first-time cannabis grower.
So if you use 150W of CFLs (as recommended to start with each plant below) you can expect about 37.5 grams, or a little over 1 oz per plant. If you add more CFLs for each plant, you will increase your yields somewhat proportionately to how many watts worth of CFLs you add.
The size and shape of your plant is going to have the biggest effect on both your cannabis yields and how many CFLs you’ll need. That’s why no “formula” is going to be accurate all the time; marijuana plant training makes such a big difference on your final yields and its impossible to know what a grower’s skills will be. That means any formula is just a rough estimate, but if you follow the steps in this CFL growing tutorial you’ll produce great results every time so you get the cannabis CFL yields you expect, or even more!
Examples of Cannabis CFL Setups – How many CFLs Should I Get For Each Cannabis Plant?
Expect 1 ounce of bud for each
Don’t want to think about it? Here are example setups as far as how many and what kind of CFLs to get for each marijuana plant! Getting many bulbs tends to work well, but getting all those light sockets and arranging all the lights in an easily adjustable way can be a pain. Larger bulb setups let you use fewer bulbs in total to deal with, and have slightly increased penetration, but as they continue to get bigger they become more unwieldy and start generating a lot of heat.
Each CFL Setup Example is For One Cannabis Plant – Expect a Little Over 1oz of Bud
A grower can expect a little over 1oz/plant with each of these CFL Setups, as long as they take great care of their plants, and train them to grow short and wide with many colas as outlined above in the step-by-step instructions above in this Growing Cannabis with CFLs Tutorial.
A.) Small Size CFL Bulb Setup
B.) Medium Size CFL Bulb Setup 6500k colored bulbs (Sometimes called Cool White, Bright White, Daylight)
Best suited to Vegetative Stage
By using the 6500k (sometimes “65k”) colored bulbs during the vegetative stage, you’ll be giving your plants more blue light, which can help a plant grow more short and bushy.
However, you can still use bending and training to make your plant grow however short and bushy you want, no matter how it grows!
2700k colored bulbs (Soft White, Warm White)
Best suited to Flowering Stage
The soft white 2700k colored bulbs have more reds/yellows that help your plant “get in the mood” for making buds
Mix Different Color Bulbs Together
Best suited to Any Stage of Life
An incredible example by grower iskraiskra
What About (5500K) Photography CFLs?
“Will a 5500k or 5000k photography CFL bulbs work for growing weed? I know you’re supposed to get 6500k colored bulbs in the vegetative stage, and 2700k colored bulbs for flowering…”
“I have a 150w 5500k photography bulb which looks identical to other bulbs rated 5500k specifically sold as ‘grow bulbs’ so could this be used for growing marijuana?”
Any CFL will work for growing marijuana. Again, it’s much more important to get a high wattage than the right color spectrum. Wattage = light = yields. I’ve used 5500k photography CFL bulbs in the past and they worked well.
As far as spectrum is concerned, blue (6500k) encourages shorter vegetative growth, red/yellow (2700K) encourages longer/taller vegetative growth and flowering/bud development. The 5500k bulbs are in between. However, I’ve found they can all be used successfully in all stages of growing.
What has a greater effect on your results is how much light (wattage) in total. More light/wattage is better with CFLs. For example, I’d rather have 150W of 5500k bulbs than 100W of 2700k bulbs for flowering. The increased light intensity will help your yields more than getting the exact right color spectrum.
The increased wattage will give you more return on yields than getting the proper spectrum, so choose the cheapest CFLs you can get that will give you the most wattage!
Light Sockets & Splitters
Make sure to get a light socket for each CFL bulb! This is what you use to get light to your bulbs from the wall.
Get a light socket for each CFL bulb!
A common method for setting up CFLs is to use a 2-way or 4-way splitter plus a light socket extender to fit more bulbs into a clamp light socket (without the extender, they might not all fit inside the reflector).
Left – a clamp light socket. Right – two CFLs on a 2-way splitter on an extender.
As a bonus to doubling up, setting up more than one bulb per socket can often be cheaper than buying an individual light socket for each light, especially if you buy online. It also is really convenient for arranging CFL bulbs around your plant.
Over the years I’ve seen many creative solutions for setting up CFLs above cannabis plants indoors! A large part of using CFLs is improvising ways to get them in a proper position close to your plants!
Light splitters like the following are a helpful way to get more CFLs in a smaller place. They also help you use less total light sockets which can save you some money.
Environment & Reflection – reflect light at your plants for bigger yields
Use the power of reflection to minimize light loss in your marijuana grow space. Cover your walls with something reflective like flat white latex paint (which has 85-95% reflectivity) and/or utilize reflectors to aim more light where you want.
Make walls of grow space more reflective to get more light to your plants. A common way to quickly add a lot of reflectivity is to paint walls with flat white latex paint – simply painting your walls with this specific type of paint is really cheap but effective!
Use reflectors (or make your own like WasabiMayo does below!)
Learn more about increasing your yields with reflectivity
If you don’t have a good growing space, you can easily buy one that’s perfect for growing cannabis with great reflectivity! A 2.5’x1.5’x3′ grow tent is great for small spaces when growing cannabis with CFLs. If you have more space, a larger grow tent model will give you a lot more flexibility as far as accessing your plants and being able to arrange your lights. These grow tents are optimized to be as reflective as possible, which increases your yields with the same grow lights.
This grow tent is 2’ x 4’ x 5’, which is a good starting tent size that can be upgraded with bigger grow lights later. The inside walls of a grow tent are specially made to reflect the light from grow lights onto your plants.
(choose whether you plan to grow in soil, coco coir, hydro, etc)
- If you’re not sure, I recommend starting with coco coir since I believe it’s one of the easiest and most forgiving ways to grow marijuana. It’s how I got started and I think it’s the perfect way to learn how to grow cannabis without spending a lot of money. Feel free to read my complete guide to growing cannabis in coco coir with CFLs!
- Hydro will give you faster growth and bigger yields, and it’s actually not as hard as people make it out to be.
Learn more about different growing mediums.
- If you’re not sure, a simple but effective nutrient system is from Dyna-Gro. It works great for growing cannabis yet it’s cheaper than most cannabis nutrients. You will need to get a bottle of both Grow & Bloom. “Grow” is used during the vegetative stage, and “Bloom” is used in the flowering stage. Dyna-Gro can be used at half-strength (compared to what it says on the bottle) to grow cannabis in soil, water, coco coir, or any growing medium.
- When growing in coco coir, I personally use the General Hydroponics Flora trio plus Calimagic (a Cal-Mag supplement) at half strength.
Learn more about cannabis-friendly nutrients
Dyna-Gro Grow & Bloom cannabis nutrients work great for growing marijuana. Use “Foliage Pro” for the vegetative stage and “Bloom” for the flowering stage (use at half strength compared to what it says on the bottle). The two-part nutrient system works great for growing cannabis in any grow medium!
pH Test Kit or Pen
- You should get either a pH test kit with drops or a pH Pen before you start growing cannabis – it’s important to test pH in order to avoid getting nutrient deficiencies
- Soil: Maintain 6.0 – 7.0 pH
Hydroponics: Maintain 5.5 – 6.5 pH
An electrical timer is used to make your lights go on and off on a schedule.
- The timer I use cost about $10 and has served me well for multiple grows, but any electrical timer will work great.
To all you growers on a budget: It’s possible!
Check out WasabiMayo’s amazing (and budget) CFL microgrow in pIctures…
I’m still not sure which grow lights to get… You may be interested in this discussion on the pros and cons of CFLs vs other grow lights for a small space Learn more about CFLs vs other popular types of cannabis grow lights
I want to see a real CFL grow in action! Show me a CFL dresser microgrow with lots of pictures: CFL Micro-Grow Pictures – Week by Week
I’m definitely choosing CFLs… if you know you’re ready to get started growing with CFLs, click here to view my step-by-step tutorial on growing weed with CFLs in coco.
I’m thinking about choosing HPS grow lights instead… Help me get started using HPS grow lights
CFLs are available everywhere… giving you a cheap & stealthy way to start growing weed in a cupboard, computer case, or small closet. Learn how…
Easy Beginner Grow Cannabis Guide w/ CFL Grow Lights | How to Grow Marijuana
Table of Contents
This easy indoor hydroponic cannabis grow guide uses common CFL bulbs as grow lights and forgiving coco coir as a growing medium. It’s designed for the beginner as a cheap and easy way to introduce yourself to growing marijuana.
Growing weed doesn’t have to be hard!
Startup Cost: Around $300 to get started
(materials listed here)
Maintenance Cost: $50/month
Yields to Expect: 1-3 ounces/plant (if you follow the directions in this tutorial)
Time to Harvest: An average CFL cannabis grow takes about 12 weeks from seed to harvest. Some strains (like auto-flowering cannabis strains) can be ready as soon as 8 weeks from seed. With other strains, you may need 14 weeks or more to get to harvest (learn how to get to harvest sooner). Strain choice is very important when it comes to timelines! Learn how to find the right strain.
Recommended For: People who want a super-cheap, super-easy grow style.
Don’t be fooled just because it’s easy. Even though I was a complete beginner when I started, I ended up getting 6.2 ounces of dried buds off my very first cannabis plant from my very first grow, which I grew using this system! (Pics below). That is an unusually lot of cannabis for a CFL grow, and took using a LOT of bulbs, but if you read through this whole tutorial you’ll learn step-by-step how you can do it, too.
It helps to use a high-yielding strain (Northern Lights is great because it’s high-yielding, tends to grows short, and is low odor).
I also train my cannabis plants to take advantage of the great light that CFLs produce within 2-8″ of the bulb.
These results are not typical for your first try unless you’ve put in a lot of extra research and really watch and tend to your plants throughout your grow. Which brings me to my next point.
This method is not for everyone!
That’s because growing weed with CFLs isn’t the highest yielding method. It doesn’t get the most yields for the electricity, it’s not suitable for a large grow, and it’s not going to work if you aren’t willing to watch over your plants closely throughout the grow.
But it’s super cheap, super easy, and if you just need a few ounces of bud every few months, it may be the perfect “low-maintenance” way for you to grow weed!
I think it would be safe to assume that even a beginner can expect to get 1-3 ounces of dried buds per plant if you just follow these instructions. Even if you mess up (and you will), you’ll still get at least that if you can get your plants to harvest.
Here’s a pic of my very first grow using this method!
You will be growing your marijuana plants indoors in a soil-less medium called Coconut Coir (often called coco coir, or even just coir). Coco coir is a natural fiber made from the husk of coconuts that naturally stimulates the roots of plants and is forgiving when growing marijuana.
For feeding (water plus nutrients), you will hand-water them whenever your plants get dry and you will provide them with all the nutrients they need right in their water.
For lights, all you need are some cheap CFLs (Compact Fluorescent Lights) like the ones you get from your local hardware store.
These common bulbs are much more efficient than old-fashioned light bulbs (which can’t be used to grow plants) and CFLs don’t use much electricity or produce as much heat compared to some other grow lights.
For a stealth marijuana grow inside a tiny space, nothing can beat CFLs as marijuana grow lights.
Because CFLs have a short light range (8-12 inch max), this tutorial works best for growing plants that are kept shorter than 3-4 feet. You want to focus on training your plants to grow wide instead of tall.
That means you will choose either…
- A compact grow when you keep your marijuana plants small and harvest often (great choice for beginners who want a quick harvest) OR
- A controlled grow where you allow your plants to get bigger / wider, but you maximize the CFL light range by training your marijuana plants to grow short and bushy. This is a great choice for growers who don’t mind waiting a few more weeks in order to get a bigger harvest.
You can still get at least a couple of ounces off each plant, even when plants are kept short and you will be able to harvest your crop in only 3-4 months.
This system reduces many of the problems associated with an indoor soil grow, and is also much easier than almost any other hydroponic style grow.
It is a great way to learn about how marijuana plants grow and after doing one harvest yourself, I guarantee that you will start getting millions of ideas on how you want to do your next grow.
Pros of Growing Marijuana with CFL Grow Lights and Coco Coir
- Cheap and easy to start
- Cheap and easy to maintain even for a complete beginner
- Forgiving way to learn how to grow weed
- Perfect for growing 1-2 plants
- Get 1-3 ounces/plant (harvest yields depend on the strain, how big you grow your plant ,and the light intensity you provide to the buds during the flowering stage)
- High quality bud since the plant is fed hydroponically
- Suitable method for a very small grow space
- Can be used with any strain of marijuana, whether starting with seeds or clones
- If you ever upgrade down the road, you’ll still be able to use all this equipment for seedlings and vegetating marijuana plants; this setup is easily turned into a dedicated vegetative chamber
Cons of Growing Marijuana with CFL Grow Lights and Coco Coir
- CFL grow lights are not cost effective when growing more than 1-2 flowering marijuana plants at a time, if you’re growing more than a handful of plants, you’ll probably want to invest in a LED Grow Light or LEC grow light to supplement your light intensity. Learn about the various marijuana grow lights you can add if you want to really ramp up your yields (instead of just trying to add more CFLs).
- Hand-watering plants is simple, but can be a pain if you have a lot of plants OR very small pots (which need to be watered more often)
- You have to adjust your CFL bulbs 1-2 times a week, as your plants will be rapidly growing into them
- For best results and to be able to harvest several ounces/plant with this method, you will need invest your time to learn how to keep your marijuana plants short with basic marijuana growth control techniques
This is really a perfect way to grow your first harvest if you “just want to get your feet wet” because it’s low cost and so forgiving it’s hard to mess up. Plus, you will really learn an incredible amount about cannabis growing by using this method.
I used this technique for my first grow, and even though I made a lot of mistakes, my plants produced great buds.
What you will need
- Marijuana Seeds or Clones
- High-quality hydroponic nutrients which are designed for growing marijuana hydroponically. Any quality cannabis nutrients made for hydroponics will work well as long as you also use a Cal-Mag supplement. I personally use the General Hydroponics Flora trio plus Calimagic (a Cal-Mag supplement) for growing in coco coir. This is a tried and tested nutrient system for any type of hydroponic growing. You can actually follow the nutrient schedule on the bottle because it’s formulated for plants like cannabis, just start at half-strength. Here is the exact nutrient schedule I’m using right now from them (pdf). I also recommend Fox Farms Hydroponic Liquid Nutrient trio since that’s what I exclusively used with good results on my first grow. Learn more about different cannabis nutrients.
- Pots to plant your marijuana in. Learn all about cannabis growing containers. Since you want to keep plants relatively small when growing cannabis with CFLs, you’ll generally want smaller containers (1-3 gallons each) for your plants. If you do get bigger containers (5+ gallons), you should still start your plants in smaller containers until they outgrow the current one and need a larger pot.
- Coco Coir Potting Mix. You can buy done-for-you Coco Coir potting mixes online or at hydroponic garden stores, which can be used immediately just like regular soil. But the cheapest and most widely available type of coco coir for growing comes in brick form. Here’s a tutorial showing you how to hydrate coco coir bricks into a nice fluffy soilless coco mix that your plants will love.
- CFLs (Compact Florescent Lights). You want at least two 40W ‘daylight’ CFLs to start (note: a 40W CFL is the same as a 150W incandescent equivalent, don’t let them trick you). You’ll be adding more CFLs as your plant grows and needs more light. You should plan on getting around three more 42W ‘soft white’ CFLs for the flowering stage. CFLs are found everywhere, in stores and online. For growing cannabis, I like bulbs close to the 40W range because they are a small, manageable size but still produce a lot of light. By the time your cannabis is flowering (making buds), basically the more light the better. When it comes to CFLs, you pretty much can’t give your plant too much light. It’s optimal to use ‘daylight’ (6500k) colored bulbs for the vegetative stage and ‘soft white’ (2700k) colored bulbs for flowering, because this more closely matches what the sun is doing in summer and fall, but you can use any color spectrum CFL during any stage of life and your cannabis will grow well. The total amount of CFL wattage you give your plants is much more important than the color spectrum of the bulb. Learn more about how many CFLs to use for the yields you want.
- Enough light sockets for all your lightbulbs – they’re about $5 apiece at my hardware store, and a few bucks more online. Sometimes they also come with some sort of clip you can use to clip your lights anywhere. A 4-way splitter is a great way to get more sockets in a small amount of space for less money.
- A timer to make your lights go on and off when you want. You can get a cheap mechanical one or spend more for a nice digital one, and they’re found in hardware stores or online. The timer I use cost less than $10 and has served me well for years. You don’t necessarily need a timer to start growing, but you will need one by the time you start flowering your plant (about a month in).
- pH Control Kit: This contains pH Up and pH Down (to adjust pH of your water) and a simple strip test. Another option for testing pH is a fancy (and more expensive) digital pH tester though my plants did just fine with the strip test that comes in the much cheaper pH Control Kit. All hydroponic stores and some gardening stores with sell pH Control Kids. You will want to adjust your water so it’s around 5.5-6.0 pH when you water your plants. How do I check and adjust the pH of my water?
- (Optional)Grow Tent: If you don’t have a good growing space, you can easily buy one that’s perfect for growing cannabis! A 2’x2’x4′ Grow Tent is great for small spaces. If you have more space, a larger model such as a 2’x4’x5′ Grow Tent will give you a lot more flexibility as far as accessing your plants and being able to arrange your lights. You can also use a 2x4x5 with bigger grow lights such as a 250W HPS or even a 400W HPS, so you’ll have the ability to upgrade your grow down the road. I always recommend getting the biggest grow tent size you can fit, as you’ll always wish you had more room! Learn more about using grow tents for growing weed.
Estimated Total Cost for Growing One Plant
- Seeds or Clones – Free – $10+/plant (learn how to get marijuana seeds in the US)
- Nutrients –General Hydroponics Flora trio plus Calimagic (a Cal-Mag supplement) – $55
- Coco Coir – $20 for a done-for-you bag of coco mix, or about the same for a coco coir brick + perlite. (learn how to rehydrate a coco brick)
- Container – 2 or 3-gallon pot – $1 – $8
- Two 40W ‘daylight’ CFLs for the vegetative stage – $20
- Three 42W ‘soft white’ CFLs for the flowering stage – $35
- Light sockets – you need a light socket for each of your CFLs. They usually cost less than $10 each, and you can get cheap 4-way splitters to be able to use less sockets/cords for even cheaper. For five sockets (to account for your five CFLs), it will run less than $50.
- Light Timer – An average timer costs about $10 though some digital ones can cost $30 or more
- pH Kit – A complete pH kit costs $10 – $30
Total Startup Cost for One Plant: $201 – $258
Each additional plant needs an additional container, coco and 5 more CFLs and light sockets, for an additional setup cost of about $100/plant.
Important! If you plan to grow more than 2-3 plants, I highly recommend upgrading to a small LEC, LED or HPS grow light as you will get a better “bang for your buck” than with CFLs as far as yields for electricity. An LEC, LED or HPS will yield 2-4 times as much bud as you would get with CFLs for the same amount of electricity. CFLs are much better suited for just one or two plants, or for growers who want to “dip a toe” in growing without investing too much.
So, you can see that it doesn’t cost that much to get started growing cannabis with CFLs! After you get going you can expect to spend about $30/month in electricity, supplies, etc. considering an electricity price of $0.12/kWh (average cost of electricity in the US). So, if you harvest in 3.5 months, which is the average time, you’ll have spent about a total of $300 – $360 for your entire first grow, including setup, electricity, nutrients and maintenance. After that you can expect to pay about $100/grow since you won’t have to invest in most of the setup costs again.
Spend about $300 and Harvest 2+ Ounces From One Plant!
2 ounces (
60 grams) per plant of bud retail value: You may get even more but a reasonable estimate for someone who follows the directions is to harvest at least two ounces of dried bud from each plant. At $10-$20/gram (prices around here), two ounces of cannabis is equal to $566 – $1133 which is worth much more than the money you need to put in to get started. And the amount you spend will go down each grow, while your yields will likely go up. Plus, you don’t have to go anywhere to get your buds! I got a total 6.2 ounces of dried buds off my first cannabis plant I grew using this system (pictured below in flowering section) but to get those kinds of results you need to train your plant and invest in more CFLs as the plant get bigger to make sure there aren’t any shadowy areas.
After your first grow, you will only need to get more plants, more coco coir, and more nutrients which will significantly bring down the start-up costs for subsequent grows.
Remember, you can start out with fewer lights and light sockets (start with 2 per plant), and will only need to get more as your plants get bigger. The great thing about all of the items needed for this technique is they can all be used in future grows, even if you decide not to continue with this method. For example, even if you end up getting more powerful grow lights eventually, you will always be able to use the CFLs for starting out new plants, or for adding additional side lighting.
A Note about Using CFL Lights
You need about 80w of CFLs per plant to start; I prefer to start with two 40W per plant
This is what I use for each plant:
- Two 40W ‘daylight’ CFLs to start
- When the plant starts budding, I recommend adding at least an additional three 42W ‘soft white’ CFLs for the flowering stage. You can add even more if you have the space. More light = more bud when it comes to CFLs in the flowering stage.
These lights are easily found at the store or online. You can get lower or higher wattage bulbs, but I like bulbs close to the 40w range because they produce a lot of light, but are still a small, manageable size.
You’ll likely need to add CFLs a little as a time while your plant grows, but by the time the plants are flowering, you definitely want more light than your original two bulbs to get your plants to produce lots of bud. Light is what gives your plant energy, and the more energy it gets, the bigger buds it will grow.
More Light = More Bud
(up to a point)
It’s optimal to use ‘daylight’ (6500k) colored bulbs for the vegetative stage and ‘soft white’ (2500k) colored bulbs for flowering, but you can use any color CFL during either stage and your plant will grow well. The color spectrum of the bulb is not nearly as important as the total wattage.
Instead of just plain sockets, you may decide to get some heavy duty clamp light sockets which you can use to power your light bulbs. These light sockets have a reflector built in and are able to clamp to most anything.
When looking for clamp light sockets, avoid anything that’s made of plastic (it’s cheap and will break) and try to find something with at least a 9-foot-long cord. You might be surprised at how annoying it is to try to find a way to make a 6-foot cord work.
To maximize the light your plants are getting, you can use a 2-way or 4-way splitter plus a light socket extender to fit more bulbs per each clamp light socket (without the extender, they might not fit inside the reflector).
Setting up more than one bulb per socket can often be cheaper than buying an individual light socket for each light, especially if you buy online. It also is really convenient for arranging around your plant.
An incredible CFL grow light setup by grower iskraiskra
How to get started
Optionally fill the first couple inches of your pots with perlite for extra drainage, and then fill the rest of the pot with coco coir.
Note: Perlite can often be found in garden stores or the garden section of places like Home Depot and Lowes. I normally advise against all things Miracle-Gro, but their 8-quart bag of perlite is okay for this tutorial if you can’t find anything else. But remember, never use Miracle-Gro time release soil or their standard nutrient formula! But their perlite is okay.
Water your pot with coco coir thoroughly until water drains out the bottom before adding your seeds or clones.
Set up your lights so that they can start around the height of your pots and eventually be raised to the final height of your plant (2-3 feet depending on your marijuana strain and how long you let your plants stay in the vegetative stage).
Once you have everything set up as described, simply add your marijuana seeds or clones and set up your lights so that they’re about 4 inches away to start.
You will want to start feeding your plants with nutrients at quarter strength for the first week, then work your way up to full strength slowly.
I recommend following the instructions exactly as provided by the nutrients.
For example, if you are using Fox Farms Hydroponic Liquid Nutrient trio, just follow the feeding chart that comes with the bottles and water your plant with nutrients every other watering.
When not using nutrients, make sure you still pH your plain water before your feed your marijuana!
This is important! Water your marijuana plants until you get at least 20% extra runoff water out the bottom.
Then don’t water your marijuana plants again until the top of the coco coir starts feeling dry.
This will start out with you watering the plants every couple of days, and may end up with you watering them once a day towards the end of the marijuana flowering cycle.
This bears repeating, you want to ensure that you have about 20-30% extra run-off water come out the bottom of the container every time you water your plants.
The reason for this is that coco coir tends to form natural salts if it the fertilizers just sit in there and never get washed out. Making sure you keep adding water until you get run-off is also a great way to make sure that your plants are draining properly.
As I said before, make sure to feed your marijuana plant with plain, pH’ed water every other watering.
This will greatly help reduce the amount of salt buildup and prevent nutrition problems from occurring. If your marijuana shows signs of drooping, chances are you are over or under-watering.
In order to prevent over or under-watering, make sure you water thoroughly every time, and wait to water again until the top inch of coco coir feels dry.
After your plants have grown accustomed to their new environment (after a couple of days for transplanted clones, or when your seeds grow their second set of leaves) then you will want to move your CFLs so that they are about an inch away from the plant.
CFLs lose a lot of light the further away they are and their light is almost useless once the plant is 6-8 inches away.
Your biggest task when growing your marijuana will be adjusting the lights.
The CFL bulbs should always be as close as possible to the plants, yet they need to be far enough away that your marijuana doesn’t grow into the lights and burn its leaves.
If you check on your plants constantly, you can keep the lights closer. If you’re going to be away for a while, you should move the bulbs away to give your marijuana some growing room.
Personally, for me, adjusting the lights was one of the most fun parts of growing marijuana using this method because it gave me something to do while I was hanging out in my grow room.
As a beginner, I always wanted to keep checking in on my marijuana plants all the time, and adjusting the lights gave me something I could do to satisfy that urge. You may also want to rotate your plants every day in order to provide the evenest amount of light from all sides.
Your marijuana can’t get really get too much light from CFLs and the only thing you need to worry about with the CFLs is burning your plants if they get too close.
Basically, if you put your hand where your plants are closest to the light, and the light feels too hot to be comfortable, then the light is too close. If your hand just feels warm, but not hot, then your plants are at the perfect distance. I generally kept my CFL bulbs 2-4″ from the leaves during the whole grow.
If you notice that your plant is growing with a lot of space between nodes or otherwise seems like it’s ‘stretching’ upwards, that means that it probably needs more light. Try adding an extra CFL or two or move them closer. If you notice your plant is having any other issues or something doesn’t seem right, check out the Plant Problems and Symptoms Guide.
When your cannabis plants are about half their final desired height, you will change them over to the flowering stage so they start growing buds.
By half the final desired height, I mean, if you wanted your plant to achieve a final height of 2 feet, then you would switch your marijuana to flowering when they’re about 1 foot tall, or half of 2 feet.
If you wanted your marijuana to grow to be 5 feet tall, then switch them to flowering when they’re at a height of 2.5 feet.
The reason for this is that marijuana will generally double in height after being switched over to the flowering stage.
To initiate the flowering stage, you will switch your light schedule so that your lights are on for 12 hours a day, and off for 12 hours a day.
During the ‘off’ period, your marijuana should be in total darkness.
This light schedule will trick your marijuana into thinking that the days are getting shorter and fall is coming.
The 12-12 light schedule will cause your plants to begin the flowering stage and start focusing on making buds instead of just growing.
If you don’t change your schedule to 12-12, chances are your marijuana will just keep growing forever and never make buds.
After switching to 12-12, you should start noticing your plant making its first sex organs after a week or two. Females will grow white hairs and males will start growing grape-like balls.
In order to maximize the amount of bud you get, you will want to make sure you remove any males so they don’t impregnate you females. If they stay together than your females will get pollinated by the males and will end up making lots of seeds instead of buds.
Unless you have a reason to keep males (for example breeding), you probably want to just kill any male plants because they won’t make any usable bud anyway.
When growing with CFLs, it becomes harder and harder to fully illuminate the plants as they get bigger and grow more branches. You will maximize the total amount of buds you get by keeping the plant smaller (and therefore easy to bathe in light), and then harvesting more often since your plants will be ready to harvest much sooner.
As the plants get taller and start blooming, you may need to get a couple more CFLs to light them from the sides. Basically if you see any dark or shadowy areas that are more than 6 inches from a CFL, then you should get another CFL to plug in that ‘hole.’
Towards the end of the flowering cycle, as your marijuana approaches harvest time, you may notice that some of the oldest leaves start turning yellow and falling off. This is totally normal and is a sign that your plant is taking nitrogen out of the leaves and putting them into the buds/flowers.
You will want to stop feeding your marijuana any nutrients for the last two weeks before harvest to ensure the best tasting bud. Simply feed them plenty of water without nutrients for these last two weeks, but make sure you’re still adjusting the pH so they absorb any leftover nutrients in the coco coir.
I usually stop feeding my cannabis nutrients and start feeding them water when about 75% of all the pistils (hairs) have turned dark and started curling in towards the buds.
Please view the Harvest tutorial for more information about when and how to harvest your plant. This guide will tell you exactly what to look for as far as determining if your cannabis is ready for harvest.
Basically, you’re waiting for your cannabis flowers (which are initially covered in straight white hairs) to darken and curl in. When the buds are ready to harvest, nearly all the white hairs/pistils will have turned orange and curly.
When using this method, I’ve found my cannabis to be really resistant to issues or problems, especially considering this method was the one I used for my very first harvest and I had no idea what I was doing when I started.
Over the course of my first grow I made several mistakes, including dropping a light on one of my plants and accidentally burning some of the leaves on the lights. Every time something happened to a plant, it seemed to take it in stride and just keep growing.
Despite all my mistakes, I still got 6.2 ounces of dried buds off my first plant grown with this grow method!
I really like this technique for a beginning cannabis grower because it’s a really good way to get a feel for how plants grow and how the cannabis plant grows in particular.
It can be hard to decide what you want to do for you first grow, and this is a really cheap yet effective way to get started with growing and get good results.
After having one successful grow under your belt, I guarantee that the whole process will start making more sense.
Even if you end up eventually moving on to other types of growing systems, you will be able to use many of the materials from this system with your future grow.
If you end up using this technique or have any other thoughts or comments I’d love to hear from you!
This easy indoor hydroponic cannabis grow guide is designed for the beginner as a cheap and easy way to get started with growing cannabis. Anyone with $300 and a closet can grow up to five plants!