cloning marijuana plants in water

How to Clone Weed in a Cup of Water (Easy!)

Did you know you can clone cannabis by putting a piece of a branch in water? Just leave your cup in a warm sunny spot and wait 2-3 weeks for roots to form (some plants take longer or shorter).

Who doesn’t want a bunch of free plants when it’s that easy?

Each of these cuttings is an exact copy of the “mother” plant. As a result, you know that all these clones will grow pretty much the same as each other (and their mum). Cloning is also a great way to produce a lot of plants at once for basically free. If buying seeds is too expensive (and creating your own seeds isn’t feasible), then cloning can make growing a lot more affordable. Cloning via the “cup method” is easy and doesn’t take much space, effort or equipment.

This tutorial will teach you how to make rooted clones like this in a cup of water (it’s easy!)

How to Clone Cannabis with the Cup Method

This section will take you through the process of cloning step by step. First, you will need a few supplies…

Supplies list

  • A cannabis plant with at least 7″ long branches (these stems will become your clones)
  • Sharp scissors
  • Fresh clean water (spring water is great, but any human-drinkable water will work)
  • A cup or container to put your clones in

Supplies needed for this cloning tutorial (cannabis plant, scissors, water, and a cup)

Optional but not necessary

  • General Purpose or Vegetative nutrients (FloraNova Grow is a great one-part nutrient for vegetative growth) – add to your water at seedling strength, or just give plain water
  • Cloning powder and/or cloning gel

The little plants in this picture used to be branches on the plants behind them. Each is a genetic copy of their “mother” plant.

Will using clear cups hurt the roots? I’ve tried cloning in clear and not-clear cups. As far as I can tell, it didn’t seem to make a difference in rooting rates. I would avoid letting direct light shine on the roots and make the water hot, but a little ambient light doesn’t seem to bother them. After trying it both ways, I personally use clear cups so I can easily see the roots as they form, but any cup or container will work.

I’ve cloned in clear cups and opaque cups like this. Both seem to work great!

You can clone cannabis in basically any cup or container. This clone made roots in a glass beaker after being left on the kitchen counter.

Step-By-Step Cloning Instructions

If this is your first time taking cannabis clones, I recommend only taking cuttings from a vegetative plant that hasn’t started flowering yet. A vegetative plant is only growing stems and leaves, but no pistils or buds yet. Plants in the vegetative phase tend to root more quickly and easily. On the other hand, clones taken during the flowering stage may take longer to make roots, and sometimes display odd growth patterns for the first few weeks after rooting. Some people take flowering clones on purpose to take advantage of those growth patterns. This is known as monstercropping but is considered an advanced growing technique.

The goal is to have a rooted clone by the end of the tutorial. Then I’ll show you how to plant your clone in soil, coco, or hydro.

Step 0 – Prepare for cloning

Get all your supplies ready before you get started. Get your plant, your glass of water, your scissors, and put them all in the same place so you can smoothly cut clones and stick them immediately in water.

Prepare your space with your plant, scissors, water, and cups. Don’t forget to label your cup with the strain name!

What about cloning gel or cloning powder? You can dip the ends of stems into cloning gel and/or cloning powder, which may help them root more quickly. Many growers find they help plants root faster, but when it comes to this method, I’ve never really noticed much difference between clones that get dipped vs not dipped. However, it definitely can’t hurt and may help you in your individual environment.

What’s the best water to use? Spring water is my favorite water for cloning (or growing) weed. It doesn’t have all the minerals removed like filtered water or distilled water, and often has a lot less extra random “stuff” than tap water. Plants typically respond well with spring water. That being said, I don’t have the option to use spring water all the time so I use regular filtered or tap water. Our local tap water is not great, with high PH and PPM. Yet it works great for growing and cloning weed as long as I correct the pH. Based on my experience talking to other growers, it seems like nearly all human-drinkable water sources work to grow weed as long as the pH is adjusted to be in the correct range.

If your tap water is good enough to drink, it’s good enough for cup cloning (as long as you correct the pH!)

Should I use nutrients?

You can clone cannabis in straight spring water. However, I personally like to give them a very small dose of nutrients in their water. If you already have nutrients you plan to use during your grow, I recommend using those at what’s listed on the bottle as “seedling strength”. If not, simply use half of what you would use in the vegetative stage. If you’re not planning on using nutrients during your grow (for example if growing in super soil), then it may be easier to stick with plain water for cloning so you don’t have to buy nutrients just for this part.

Step 1 – Identify which branches are at least 7″ (18cm) long on your vegetative plant

For first-time cloners, I recommend cutting clones that are around 7″ (18 cm) tall. That means you need to identify which branches on your plant are at least that long or longer. This size will fit in a typical drinking glass with the leaves able to reach over the top of the glass and “spread their wings” to the light.

Your clones should be big enough to reach over the top of your cup

You can cut a clone that’s shorter than 7″ (I’ve successfully cloned a stem as little as 3″ tall). However, shorter clones typically take longer to root. I had one 4″ cutting that didn’t make roots after several weeks. Out of curiosity, I just let it keep going and refilling the cup as the water level got low. I was amazed when it finally sprouted roots 2 months later. If your stems aren’t long enough yet, follow the tips below to get them to quickly grow longer.

How do I make my plant produce longer stems for clones?

  • If the stems on your plant are too short (or there aren’t many suitable clone sites or offshoots), you need to encourage the plant to branch out and give the stems time to lengthen
  • If you haven’t yet topped the plant, do it now (cut off the top tip of the main stem). This will cause the plant to naturally bush out and develop more side branches.
  • A stem on the plant won’t develop without light. Try to gently open up the plant via bending and tie the tallest branches down so all the small shoots get light and start growing.
  • Give strong light to your plant so all the newly-exposed shoots grow quickly
  • But not too much light. Make sure to follow the manufacturer’s instructions on how far to keep your grow light from plants. Keeping a grow light too close to the plant can slow down plant growth to a crawl. It also tends to keep branches shorter. Learn how too much light can cause light stress.
  • Make sure to deal with any problems so your plant grows as fast as possible
  • If you follow these instructions, it should only be a week or two before you have several suitable clone sites.

This stem is 7″ long. Perfect!

What about bigger/taller clones than 7″? You can definitely take big clones. I’ve seen some growers take 12″ (30 cm) clones or even bigger, especially when using an aerocloner. Big clones can root in the right environment and one advantage is the plants are already well developed. If you’ve got long branches and want a bunch of tall plants right away, you can often turn those branches into big clones. However, bigger clones can be more likely to wilt immediately because they have a difficult time getting water to their tallest leaves and branches. The other issue with big clones is they already have a set stem structure. With smaller clones, you have the ability to shape the size and shape of the clone via plant training, which can dramatically increase your overall yields indoors under a grow light.

Step 2 – Trim the branches until there are only the top two pairs of leaves

You’re cleaning up the stems so you don’t have leaves sitting underwater in the glass. It’s easier to clean the sides of the stem now than after the clones have already been cut.

Trim the branches in preparation so they’re mostly smooth

I typically leave the top two pairs of fully formed leaves, but each clone is a little different. Make sure there are at least a few leaves left!

Step 3 – Cut off your clone and immediately put in water

It’s go time! You are about to cut your clones!

Don’t forget to label your cups with the name of the strain because it’s easy to forget which is which.

Try to cut at a 45-degree angle, and make your cut near a node/set of leaves if possible (this may help clones root faster)

Immediately place your new cuttings in water. Don’t wait or the clone may die!

The longer you wait after cutting before putting the stem in the water, the more likely air will get in the stem. Air in the stem causes the clone to immediately droop and start dying. That’s why the new cutting must be put in water immediately (just like when cutting flowers or roses for a vase).

Note: If using cloning gel or powdery, quickly dip the end of the stem first then place in water. Some growers dip in gel first, then powder, then into the water.

Some growers trim the edges of their leaves, especially big leaves. This is because the cutting has trouble getting enough water to the leaves without any roots. That’s why it’s also a good idea to trim leaves if it’s very dry where you live (the leaves evaporate water quickly in dry air, and the plant can’t keep up). It can also help to raise the humidity or use a dome to keep more moisture in the air around clones.

Trim the ends of leaves if they’re big, or if the air is dry (under 30% RH) where you live. Otherwise, feel free to leave them alone.

Step 3 – Place new cuttings in a warm bright spot to make roots

I have a sunny window that gets really warm, and that’s where I like to put the new cuttings. For the first two days, I leave the blinds mostly closed so they’re getting filtered light. After two days I’ll open the blinds and the window so they’re getting direct sunlight for part of the day.

  • Keep clones warm and humid. Roots form much slower if the air is cool or dry.
  • Give filtered light for 2 days at first so they have time to adjust
  • Then move cuttings to a bright spot with direct-but-not-intense light (for example in a sunny window or under a fluorescent grow light)
  • If you notice the water level getting low, gently top off with plain water by pouring water down the sides of the inside of the cup

Should I change the water or just leave it alone? Some growers change the water every day when cloning in a cup to help oxygenate the water, but I personally don’t do that and I’ve never had a problem getting roots to form.

This sunny window is my favorite spot for cup cloning. I angled the blinds so these newly-cut clones get filtered light for a few days before getting full sun.

Step 4 – Roots typically form within 2-3 weeks

If you’ve followed all the directions here, your cuttings should stay upright and healthy-looking the whole time. After about 2 weeks you may start seeing roots on some plants.

Plant roots look like little nubs at first

They soon develop into more recognizable roots

It’s normal if you notice the bottom of your stems turn brown. That’s just part of the process.

Different plants/strains root faster than others. I had an Ocean Fruit plant where every single cutting rooted within 10-12 days. That plant apparently loves being cloned via this method. However, certain plants/strains are just harder to clone than others. I had a Durban Poison plant that took 4 weeks before its cuttings started making roots. All the other plants had rooted all their clones before the first Durban Poison clone made roots. So if your clones are taking a long time to root, it may have nothing to do with you.

Most plants will have roots within 2-3 weeks, however, it’s normal for some cuttings to take longer than others even from the same plant. You may have some cuttings show roots at week 2, while others from the same plant show their first roots in week 4. It’s a matter of patience. I personally like taking many more clones than needed so I can keep the ones that root first. Those tend to be the fastest-growing plants anyway!

Pay attention to your clones! I completely forgot about these and when I checked on them the roots were grown together and almost all the water was gone!

If your roots grow together, they often can be untangled. Treat them as if you’re gently untangling a knot in someone’s hair. Tug softly and slowly on first one strand, then the others, giving the strands time to unravel and separate from each other. Don’t pull hard or they’ll break!

Now that you have rooted clones, it’s time to install them into their next home.

Not sure whether to put your newly rooted clones in soil, coco, or hydro? These clones can be used with any grow medium including hydroponics. Once the cuttings have made roots, you install them in your grow medium or hydro reservoir and start treating them like small plants. If you’re looking for a suggestion on the best grow medium for beginners, I’ve had consistently great results with both Coco Loco (soil-based) and Mother Earth Coco + Perlite mix (soilless).

How to Plant Your Rooted Clones in Soil or Coco

1.) Fill your cup half full (or make a 4-5″ deep hole wherever you plan to plant your clone)

2.) Add a little water to the grow medium until it is wet but not soaking, then press down slightly to make a small divet or hole for your roots to fit inside.

When planting your newly rooted clone into a grow medium, you basically want to wet the potting mix first and press down to make a slide indent for your roots.

3.) Gently place your root into the indent you created. If the root is long, you may need to wrap it around in a circle. Avoid using any force, but the roots are pretty flexible.

Having an indent will help keep your roots from touching the sides by giving you an outside “edge” to wrap your roots inside.

If the root is very long, you may need to wrap the root a lot or get creative. Just try to do your best! Once they already have a lot of roots, clones are surprisingly resilient.

If you’re worried about breaking the root, add extra water to the grow medium to make it softer.

4.) Fill the rest of the cup with soil and give a thorough watering.

Try to keep the clone in the middle and upright, but if it’s a little crooked it’s okay. Once the plant is a bit bigger you likely won’t be able to notice.

Try to hold the stem steady in the middle as you fill the cup with soil or coco

Fill to almost the top of the cup with potting mix and then add more water until moist all the way through

5.) Make sure extra water can drain out (plants love good drainage!)

Don’t forget to cut holes out of the bottom so any extra water can drain out. Roots like it wet but not soaking.

I used scissors to cut slits around the edges of the bottom of this cup in order to let any excess water drain out

6.) Give gentle light at first. I leave them in the filtered light of a west-facing window. If you put them under direct light immediately, they can droop or wilt. Once they’ve acclimated to their new home for a day or two and still look happy and healthy, you should be able to start giving them direct light. Within a week it should be growing fast and happy.

7.) Enjoy your new plants!

How to Plant Your Rooted Clones in Hydroponics

Placing these rooted clones in hydroponics is simple and quick. You could plant your clone directly in the clay pebbles, but the following system makes it a bit easier. You probably already have seedling plugs in your grow room if you’re growing with hydroponics.

1.) Get a seedling plug such as Rapid Rooters (or whatever plugs you typically use with your system).

This will be used to hold your clone and keep it anchored where you want.

Any seedling plugs will work to install your clone, but I personally like Rapid Rooters for hydroponic setups

2.) Cut the plug open lengthwise

Take your seedling plug and cut it open lengthwise.

3.) Wrap the plug around the stem of your rooted clone.

Wrap the plug around the stem. This supports the stem so it’s stable and easier to install into a hydroponic system

4.) Install the plug into your hydroponic system just like you normally would. Thread the roots through the bottom holes of your net pot (or cut a hole in your net pot for the roots if they’re too big) and fill in the rest of the way with hydroton to hold seedling in place.

Make sure there is at least an inch of air underneath the very bottom of the stem. You don’t want the water level coming up to the actual stem or it tends to get mushy and hurt the plant (same with seed-grown plants). Whenever growing cannabis in hydro, always give roots some air to breathe before they touch the water. Oxygen makes the plants grow faster and helps prevent root problems. As long as you have lots of bubbles in your reservoir, you should have enough water splashing up on the roots that they stay moist even though they’re above the water line. The roots will grow longer until they’re actually dangling in the water, and that’s when clones really take off!

Once the roots hit the reservoir your plants will take off!

How to Clone Weed in a Cup of Water (Easy!) Did you know you can clone cannabis by putting a piece of a branch in water? Just leave your cup in a warm sunny spot and wait 2-3 weeks for roots to

Cannabis Cloning Made Easy… Roots in 7-10 Days!

Hey everybody, it’s Mr Green here from with some free advice about making cannabis cloning as easy and quick as possible. Today you’ll learn how to clone your marijuana plants successfully every time!

I’ve been growing marijuana on a large scale since 1990 and have made thousands of clones over the years. The following is my best advice to get your clones rooted fast, in just 7-10 days.

  • Cloning Tray (with ridges at the bottom, no holes) & 7” Vented Dome
  • Razor Blade or Exacto Knife & Scissors
  • Cloning Gel and Cloning Powder
    Note: Any brand rooting powder and gel will work for cloning
  • 2 small plastic buckets (or large mixing bowls – to be filled with water)
  • Spray Bottle/Mister
  • “Jiffy 7” Compressed Peat Pellets(Recommended)
    Note: Rockwool Cubes and Rapid Rooters can be substituted
  • Grow Lights: Fluorescent Lights or Metal Halide lights (250w, 400w or 600w) seem to work best for cloning, however any quality grow light can be used.


To begin we will fill one of the small buckets with warm water. Put the other bucket aside for now, as we will use it in a moment.

Next, we soak the Jiffy 7 compressed peat pellets in the warm water, which makes the pellets expand in size, as pictured below.

Once the compressed Jiffy 7 peat pellets have expanded in warm water, we remove them one at a time.

Gently squeeze excess water from each pellet before placing in cloning tray.

Once the cloning tray is filled with expanded warm wet Jiffy pellets, we are ready to begin cutting our cannabis clones.

Let’s fill the other bucket with cold water now. We will use this to hold our new clones.

Where to cut?

When cutting clones from a mother plant it is better to cut a large section of a branch with multiple branches and bud sites.

Bigger branches will support bigger buds. A small clone may take a week or two before multiple branches appear.

This photo shows the difference between a small cannabis clone vs a big clone. You will get faster growing and more vibrant plants by choosing big clones!

Using a new razor blade, cut the branch of the mother plant at a 45-degree angle. This “branch” will be your new clone!

Place the new cutting in the small bucket of cold water you just prepared.

The stem of the cut branch will absorb some water while soaking. This prevents air bubbles from getting trapped in the stem.

If your cutting has large fan leaves you should cut the blades of the leaves shorter to fit in the cloning tray.

This way the fan leaves will still remain and speed up the growth of the new cannabis clone.

Once you have all the branches cut and soaked we are ready to dip the tip of each of the cuttings (soon to be clones) into the rooting gel.

Dipping the clone in gel first will protect the stem from getting clogged.

After the clone is dipped in rooting gel we will dip the tip into the rooting powder.

This method is what I call “Double Dipping the Clones”. I do this because some strains root better in gel, while others root better with rooting powder. This way each clone will always root no matter what. Any brand rooting powder and gel will work for cloning.

After the clone has been double-dipped, you will insert the cutting into the Jiffy 7 peat pellet.

Gently press the peat in the Jiffy 7 around the base of the stem to ensure a snug fit and to ensure contact of the peat with the stem. We don’t want the stem loose or falling out of the peat.

Note if you’re using Rockwool: Rockwool cubes usually have a small hole for the clone to be inserted. Just be sure you have a snug fit between the stem and the cloning cube.

Once all the clones are inserted in the pellets I add a teaspoon of water to the base of each stem to activate the rooting gel and powder.

The next step is to spray the clones with water before moving the clones under the light.

When spraying the clones with water make sure you spray the inside of the dome and the base of the cloning tray. Fresh cuttings need high humidity to encourage root growth.

Now place the dome on the cloning tray with the new clones inside.

Leave the light on 18 hrs per day for cloning. Try to give the clones as much light as possible. More light makes clones root faster.

About the lights:

  • If using fluorescent lights or CFLs you can keep the light 1 or 2 inches over the top of the dome.
  • If using a horizontal 400w or 600w Metal Halide light keep the light about 24 inches away from the top of the dome.

Make sure the vents of the dome are closed for the first 2 days.

Keep the room temperature slightly warm, above 20 Degrees Celsius (68 degrees Fahrenheit).

That’s it for now! You’ve made it through the first day, which means you’ve made it through the toughest part of cloning!

Remove the clear plastic dome from the cloning tray and spray the clones and inside of the dome with water.

Place the dome back on the tray when done. It is best if you spray the clones in this way at least 2 times per day.

Spraying a clone with water dilutes the nutrients in the leaves. The clone will be forced to search for nutrients once the leaves have low nutrient levels. Misting also helps maintain water levels in the plant since it can’t drink through the roots.


Spray clones once in morning and once at night.

Open the vents in the dome of the cloning tray today.

We want the moisture to escape now which will dry out the Jiffy 7 pellets. The drying of the pellets will force the small bits of root to grow quickly in search of moisture.


Keep vents on dome open and spray clones once in morning and once at night. Hopefully by this point each clone is standing up on its own.


Keep vents on dome open and check to see if pellets are dry.

If the Rockwool or Peat Pellets are dry to the touch we will add half a liter (

2 cups) of water to the cloning tray itself which will fill the grooves in the bottom of the cloning tray.

Important: If you add water, add it to the cloning tray itself to fill in the grooves at the bottom of the tray. Do not add water to the tops of the pellets at this point, or roots will take longer to form!

The pellets will absorb the water from the bottom of the cloning tray. We want the roots to search for the moisture, and forcing them to move downwards to find water will force the plant to root more quickly.

Adding water over the top of stems now will make it take longer for clones to root. Do not add water to the tops of your pellets!


Close the dome vents on Day 6.

Keep spraying clones once in morning and once at night. You should now see some roots breaking through the Jiffy 7 peat pellets for several of the clones.

We have closed the dome vents again on Day 6 because we want extreme humidity now that clone roots are starting to show. Trapping the water in the tray with vents closed creates the best environment for roots to grow rapidly.


Continue spraying clones twice a day.

By day 7, roots should be showing on at least 50% of the clones. Keep the vents closed on dome. We need to maintain high humidity until day 10.

DAY 8 & 9

By day 8 or 9 you should see roots on 90% or more of the clones. At this time you should add half liter of water (

2 cups) that has been infused with a light concentration of grow nutrients to the grooves in cloning tray.

Keep vents closed on dome which will add nutrient to the humidity in the cloning tray. Over the next day roots may triple in size.

Continue spraying with water for day 8 and 9.

DAY 10

Remove the dome on the cloning tray today to allow clones a chance to adjust to normal humidity. Clones may be transplanted to dirt or Rockwool anytime when you see roots.

If you want bigger plants, take bigger clones!

About the Bathtub Floodtable

I’ve recently been growing marijuana at home in my new condominium apartment. As a result, I needed a place to keep Mother Plants, Clones and a place to Veg the Clones.

I discovered that my spare bathroom is the perfect place for the job. The bathtub floodtable is a piece of plywood 2ft x 4ft in size. I’ve covered the plywood with 2 layers of B&W Plastic.

The plywood is raised 2 inches at the front edge of the bathtub which makes the water run downhill towards the tile wall at the back of the bathtub. The nutrient drips off the floodtable into the bathtub to be recirculated again.

View a video featuring Mr. Green’s Bathtub Floodtable

The bathtub acts as the reservoir holding the hydroponic nutrients. A submersible water pump forces the nutrients up onto the floodtable through 1/2 inch tubing that leads to spaghetti hose for each plant. Nutrients drain out of the pots while plants are being fed. This method is what I call “Flush & Feed”.

Excess nutrients are being Flushed out of the Rockwool while the Plants are being Fed nutrients.

Plants cannot be overfed with this method of hydroponic growing.

Plants are fed several times per day as programmed by a digital timer. I also have an air pump with air stone in all my reservoirs keeping oxygen in nutrients at maximum levels.

More information and instructions how to build custom floodtables are included in my book “Marijuana Mass Production Made Easy”.


I was born in British Columbia and started growing marijuana on a commercial scale in 1990. I designed and built grow rooms in nearly 20 different locations over the years, and worked as a consultant for major size grow-ops. The cover of the book has images of my basement which held 24 x 1000w HPS lights.

My education with hydroponic grow systems began in 1991 under the supervision of University Botanists who were developing a special nutrient formula for the cannabis strain Northern Lights. Since then I’ve learned advanced techniques to improve the quality and yield per light.

I’ve read dozens of books and always wanted to find one that tells the reader exactly how to get professional results without having to perform experiments, and without having to sort through pages of re-hashed common info about how plants grow. The book I wrote, “Marijuana Mass Production Made Easy” has the condensed instructions of how to average 2+ lbs per 1000w light.

I was diagnosed with Crohn’s Disease in 2012 and am now Licensed by Health Canada to Grow my own plants. All the photos and videos on my website, are from rooms I built and plants I grew.

Share my pics and videos with all your friends. My book “Marijuana Mass Production Made Easy” shows you how to grow 2 lbs or more per 1000w light and includes instructions on how to grow 12 lbs every 3 weeks in 1000 sq ft room.

The book includes the hydroponic food formula I use that will make your plants grow Bigger and Faster than ever before. I make growing easy for anyone to understand with basic instructions of what to do so you achieve awesome results every time.

Marijuana Mass Production Made Easy is available for $24.95

Get Your Supplies To Follow This Cloning Tutorial!

Cloning Tray (with ridges at the bottom, no holes) & 7” Vented Dome
Note: Because these are bulky but lightweight, these items are usually much cheaper to buy in person without having to pay for shipping (can be found at most plant nurseries and gardening stores). Although not necessary, the reason the following tray is white on top is this style helps reflect light back up at the plants (though it costs a little more than a regular propagation tray).

Cloning Gel and Cloning Powder
Note: Any brand rooting gel and powder will work for cloning

2 small plastic buckets (or large mixing bowls – to be filled with water)

Grow Lights: Fluorescent Lights (including CFLs) or a Metal Halide light (400w or 600w works great). However, you can use almost any grow light successfully as long as you keep it at the correct distance away.

Mr Green has been growing marijuana on a commercial scale since 1990 and has made thousands of clones. Learn the exact technique he uses to get clones consistently rooted fast, in 7-10 days! ]]>