This comprehensive guide will show you how to grow DWC from start to finish. Deep Water Culture (DWC) is a high efficiency low maintenance system that generates explosively fast growth. Cut veg time in half and get more bud production during flower.
Why Deep Water Culture
Deep Water Culture (DWC) is a method of hydroponic growing that I argue is easier than growing in soil. You don’t have to worry about watering schedules as your roots sit in the nutrient solution 24/7. This gives the plants a buffer where they can uptake as much water or nutrients as they require. And gives lazy people, like you and I, the ability to leave the plants unattended for days, even weeks at a time.
This website has all the information you will need to set up a run a successful DWC grow. Even if you have never grown in soil before I encourage you to start with DWC.
Thanks to advancements in LED light technology DWC can be run without any air conditioning or water chillers, as was often necessary with HPS lights. DWC maximizes yields/minimizes veg time when working under the confines of 4 or 6 plant maximums that most recreational growers face.
DWC is more simple to set up than traditional “flood and drain” hydroponics which requires piping and submersible water pumps that run on a timer (multiple points of failure).
Advantages of DWC
Rapid growth
Plants can be left unattended up 2 weeks without requiring watering
Minimal moving parts: plants will live for weeks if the air pump dies (unlike in flood and drain systems)
Low Cost: you don’t need to buy new soil every grow
Plants grow 2-3x faster
Higher yield
Perfect for working within 4 or 6 plant maximums
No nutrient waste
Continuous pH and nutrient monitoring is possible
Don’t need put your pH meter in soil runoff
Disadvantages of DWC
Water temperature must be kept below 72F (ideally 65-68F)
Root rot can kill plants if sanitary practices are not maintained
Not ideal for hot climates. Those in very warm climates may want to consider SIPs.
DWC Schematic
DWC Requirments
pH must remain between 5.5 and 6.5
Water temps must remain below 72 F
No light leaks in the water box
Need to continually aerate the water
rDWC vs DWC
Recirculating DWC (rDWC) – is a method of growing that uses pipes to combine multiple containers into a single system. Water is recirculated between the containers using pumps to create flow. The primary disadvantage of rDWC is that root rot, or other pathogens, can quickly spread through the system. Traditional DWC has a modular approach and less moving parts, so this website primarily discusses DWC.
Sterile vs Beneficial Bacteria
There are two school of thought when it comes to DWC:
Sterile DWC – involves sanitation of water reservoir, hydroton. Water temperatures are kept below 68F, light leaks are mitigated and dissolved oxygen is maximized with large air stones and strong pumps creating an environment where bacteria cannot thrive. This is my preferred method, and the one I recommend most people try first
Beneficial Bacteria DWC– involves adding products like Hydroguard to your DWC nutrient solution. The idea is that these healthy bacteria will outcompete the pathogens that cause root rot.
The most economical way to run beneficial bacteria in DWC is to brew a beneficial microbe tea. I usually inoculate my plants once or twice during the vegetative stage and never have any issues with root rot.
How To Keep Water Temperatures Down in DWC
Water temperatures must be kept below 72F and ideally below 70F in a DWC application. Any higher and you risk root rot. Some common methods for keeping water temps down include:
Keep air pump outside the grow area so you are not pumping warm air through the container
Use large totes instead of bucket for reservoir. More water = higher thermal capacity and less fluctuations in temperature
Add insulation to reservoir
If you are dealing with extreme heat I have seen redditors in California use 5 gallon coolers for their DWC reservoir
A not so cheap option is to add a water chiller to your system. I would save this as a last resort
Sub Irrigated Planters (SIPs) as an Alternative to DWC
If you can keep your ambient air temperatures below 78-80F during lights on you should be able to keep your water temps in the low 70s and should be fine for DWC. If you cannot keep your ambient temps below 80F you may want to consider sub irrigated planters.
Sub Irrigated Planters (SIPs) provide many of the advantages of DWC (e.g. not having to water frequently, no nutrient waste) without the risk of root rot in high temperature applications.
SIPs can be run both indoor and outdoor and are my preferred method for growing outdoors.
Pick a size. For flower only rooms we recommend a square box (3×3′ or 4’x4′). If you will be including a veg room a rectangular box works better (3×4′ or 4×5′). This method of growing will require a minimum height of 5′, the doctor recommends 6-7′ height if possible.
Step 2: Create a door
Make your door as big as possible, you will thank yourself when trimming leaves. Use heavy-duty T hinges.
Step 3: Paint and Seal Box
The doc recommends using glossy white paint. Conventional wisdom suggests the use of matte paints as they reflect slightly more light. This benefit is outweighed by the fact that matte paint is porous and not a good choice for a humid environment. White silicone caulk is used to seal the edges.
Weatherstripping and roller locks are used to create an airtight seal at the door.
Step 4: Install an Air Filter
Air intake filters are so important that I have an entire article dedicated to them. After trying a few types I’ve found that furnace filters are the most cost effective option. I use black plastic to create shutters that block light from getting in through the white filter.
Step 5: (Optional) – VEG room
Vegetative growth rooms have many benefits for those that do not have ready access to clones. They allow you to keep genetics alive via mother plants, propagate clones and give your new plants a kick start while your primary harvest is finishing. If you plan on starting from seed every time, or have a steady supply of clones this is not necessary.
Light Blocker: The flowering room (left) will be running lights at 12/12 while the vegetative room (right) will have a longer light cycle of 18/6. To prevent light leaks you can make a light blocker using coroplast, a hot glue gun, and a small fan. Light leaks in your flower room can cause re-vegging and should be avoided at all costs.
Step 1: Find a container with a sturdy lid and black plastic (to prevent light leaks). I always paint the lid white to help keep water temperatures down. If you live in a warm climate or anticipate high heat in your grow box this is a must.
Step 2: Put your container in the grow area to see how it will line up relative to the lights. You want to be able to remove the container(s) so don’t cram them in too tight. 8-10 gallons per 100watt of LED lighting is a good starting point. Large containers help regulate water temperatures and allow you to leave the plants relatively unattended for days, sometimes up to 2 weeks, at a time.
More plants will not get you a higher yield. With how fast plants grow in DWC it is plenty to have 2 or even just one plant in the flowering per room.
Step 3: Net Pot and Airline Holes
Drill or cut 6″ holes in the lid for the net pots. Drill a 1/4″ hole in the top of the containers for the airline intake.
Step 4: Make a gasket for the net pots to sit on. Because the lids are non-flat you will need a gasket to prevent light leaks and leaves from getting into the water reservoir. I used to use silicone but hot glue holds up better over time. Silicone does not bond to the plastic as well as hot glue does.
Step 5: Paint the Lid Black then White
The black prevents light leaks and the white helps keep water temperatures down. If your water temp exceeds 70-72 degrees F you will run into problems with root rot. If you are using black plastic you can omit the black painting step. Yellow lids need to be painted otherwise the light leaks will cause algae growth on the underside of the lid which will lead to other issues down the road. Rough up the plastic with scotch brite prior to spray painting to help the paint adhere better.
Be sure to use enough paint. It usually takes two coats of black paint to get a lightproof layer on. One can of spray paint is enough for painting five lids (17 gallon).
Step 6: Seal The Paint
If you are spray painting the lid it helps to give it a coat of krylon clear to help seal it up. Well worth it if you hope to get more than a year out of the lid before the paint starts chipping.
Step 7: Soak airstones and hydroton prior to use. Hydroton can be very dirty, rinse until the water runs clear.
Pro Tip 1: Slightly offset the Lids from the centre of the container. This will give you more room to slide the lid off to the slide when you are checking the pH and EC.
Pro Tip 2: Use a deburring tool to remove any plastic burrs after drilling out the container.
Pro Tip 3: Remove the snap on tabs. On the short ends of the lid are two snap on tabs that help hold the lid in place. These are not necessary in a DWC application, removing them helps make it easier to slide off the lid when checking pH and EC.
6" Hole Saw for 6" Net Pot
There are two types of 6″ net pots commonly available on the market. Avoid the style on the right if using a hole saw as they will fall through 6″ net holes. These undersized net pots can usually be identified by the two tabs which do nothing for keeping it from falling through.
Water Level Indicator Tubing
I used to run water level indicator tubes too as most online tutorials have them (especially on YouTube).
I now advise people to avoid them like the plague. The small benefit they provide is greatly outweighed by the risk. They sit outside of your water reservoir, so the water in there gets warm and stagnant (it is not being actively oxygenated by your airstones). This is a perfect breeding ground for bacteria that can later spread through your system and cause root rot.
I wish I did not drill those holes in my water reservoirs when I first got started with DWC as they were a pain to patch. Credit to reddit user Trees for Life for the photo above.
Bucket vs Tote for DWC
Many builds for DWC recommend the use of 5-gallon buckets (looking at you again YouTube). They will work but I do not recommend it at all. The 5-gallon bucket is simply not large enough. It negates one of the primary advantages of DWC- which is the ability to leave the plants without attention for weeks at a time. I have a friend that has to fill up his buckets daily during peak flower… might aswell be growing in coco or soil at that point.
Another drawback of the bucket system is more swings in pH and water temperature. A larger volume of nutrient solution is more resistant to these swings, especially when it comes to water temperature (which should ideally be 68F and never exceed 72F).
How Big is Too Big?
I used to reccomend people get the biggest tote they could get their hands on. After a friend setup a 480 Watt grow using a 60 gallon tote I learned that there is such a thing as too big.
The primary disadvantage is that with so much water you are going to go weeks at a time without a top up. This increases your likelihood of contracting root rot as the water is not being depleted at a fast enough rate.
The second disadvantage is that it’s a waste of nutrients. Using my calculator he was using up LITRES of nutrient solution at a time. He would often have leftover water when needing to switch the nutrient ratios to another stage of growth. For these reasons my favourite size of container is the 15-17 gallon tote. It is the perfect match for a 240W LED Panel.
You can see below what is possible with one of these totes (24k from one of my most recent harvest):
exhaust fan to draw in fresh air (unless you are doing an air conditioner cooled sealed CO2 room)
oscillating fan to circulate air within the grow space.
The exhaust fan should be used to help keep VPD in an appropriate range.
Clones / Seedlings 0.6 – 0.9 kPa
Vegetative Stage 0.9 – 1.2 kPa
Flower 1.2 – 1.6 kPa
Grow Boxes
A rigid Grow Box will allow you to securely mount your exhaust fan and carbon filter. The carbon filter can be hung from the top or mounted on top of your veg room if you have one.
Grow Tents
Tents are less sturdy than grow boxes and thus require extra care when installing exhaust fans. An improperly installed fan can pose a fire risk.
Exhaust fans in grows tents should be hung using bungee cords whenever possible to minimize vibrations to the frame. Oscillating fans like this one clip right to your grow tent poles.
Fan Size for Grow Box
I no longer recommend anyone use a 200 CFM 4″ fan unless they are only running a 100Watt LED Board. Anyone running 240W LED Board or stronger should have a 6 Inch 400+ CFM fan. Even if you are going to be reducing this down to 4″ to exhaust out of an existing dryer vent the 6″ fan will provide much faster air movement.
You always want to have excess fan power, you will thank yourself in the summer when temperatures are at their highest. It only takes one heat wave to scorch an entire batch. There are two main ways to control your exhaust fan:
Option 1: Temperature Controller
My preferred option for fan control is a temperature controller. This allows you to set a target temperature at which your fan kicks on. During veg I set my temp to 75F. During flower I lower the temperature to promote resin development and bring out purple colours.
You fan will run less during the night period when the lights are not generating heat. This will help save power. Photosynthesis does not occur during the night phase so constant fresh air intake is not required. I find this helps me maintain more stable humidity since my fan does not run needlessly during the night phase. The plants love it.
Option 2: Fan Dimmer
The second option for controlling your fan is a dimmer. This is option is not as adaptive as the temperature controller but it does let you fine tune the speed. If your grow is within earshot this can be less distracting than a temperature controller kicking the fan on and off.
Light Blocker: The flowering room (left) will be running lights at 12/12 while the vegetative room (right) will have a longer light cycle of 18/6. To prevent light leaks you can make a light blocker using coroplast, a hot glue gun, and a small fan.
Exhaust Junction
Grow boxes produce heat. I built this ‘exhaust junction’ with the idea of conserving heat in the winter months and exhausting it outside in the warm summer months.
Air Intake Filters
There is no shortage of carbon scrubbing exhaust filters for cannabis growers. Even the most basic grow setups typically have a carbon scrubber to eliminate exhaust smell.
For some reason, air intake filters are an afterthought in most grow space designs. I think this is because intake filters are difficult to incorporate into grow tents that do not have the same type of airtight seal a rigid plywood grow-box does. As we enter an era of legalization the air intake filter should become more important than the carbon-scrubbing exhaust filter that was designed to hide smells during the prohibition.
Air intake filters remove pollen, mold spores and dust mites. They will even filter bacteria (if you buy a filter with an MER of 13+). I recommend a filter with a MERV of 8 or more (MPR 600+) to filter out mold spores.
In my initial design, I used a waffle style filter that you find in most living room air purifiers.
$20 Air Purifier Filter
This worked well but these filters are expensive and even in a small 2 plant 240 Watt grow I found it to be too restrictive on airflow. I upgraded to furnace filters which are actually cheaper, I guess due to mass production. On Amazon and Costco you can readily find them for under $10 each. Get a filter with an MER of 8+ in order to properly filter out mold spores.
I decided to make a frame around the furnace filter for easy removal and so that I could add some light-blocking shutters. This is entirely optional as you could just tape the filter on to the side of your box for installation.
Slide-in Frame to allow for quick changing
My grow box has ambient light around it 24/7 so for good measure I installed light blocking shutters. If you are worried about light leaks you could also get a thicker filter. The filter above is 1″ thick but you can get them up to 4″ thick.
Installed and ready for a filter$10 Furnace Filter
Remember this is why we use air intake filters. Buds are sticky and this dust would otherwise have been stuck in your precious nugs!
I have applied this same idea to many types of grow spaces.
Scrog – stand for SCReen Of Green. It involves suspending a screen (with 2×2″ squares) 18-24″ above the base of the plants. This is essential for properly filling out your grow room and supporting the colas during late flowering. ‘Scrogging’ allows you to maximize yields while working within the confines of 4 plant maximums.
Local Classifieds or Home Building Store: 2 pcs 1/2″ PVC pipe 8′ length (pro tip: cheapest PVC is found in the electrical section and used as conduit)
I have tried a number of materials for the trellis net and have finally settled on using a very thick monofilament fishing line (100 lb test or greater). The advantages of monofilament are:
Will not pill or splinter strands of fiber like many commercial trellis nets
Easy to sterilize and clean between grows (I use rubbing alcohol to clean)
Transparent material so light can penetrate through
When using thick line it will not cut into the plants. DO NOT use thin fishing line
Cost-effective (I paid $12 for a roll that will last a lifetime)
Trellis Net Construction
I like to make the trellis net the same size as the DWC water reservoir.
Drill holes every 2-3″ and thread the 100lb monofilament line through like you would a tennis racquet.
Use zip ties or glue to secure the frame to the lid. You can even just rest the trellis net on top of the DWC reservoir without attaching it to the lid.
Use 4-way PVC connectors so that you can add 10″ risers as your plants grow. I have not found it necessary to run a second screen but it is nice to have a fence to keep taller colas from falling over
Pro Tip: If you are using 17 gallon (64L) Home Depot HDX containers you will need the following for every lid
You can use this calculator the help minimize offcuts as shown below.
DWC Nutrient Calculator
General Hydroponics 3-part (Flora Series) nutrients are an excellent choice for DWC. They provide the Nitrogen, Phosphorous and Potassium your plants need to thrive. Different ratios are used throughout the growth cycle as the plants move from a nitrogen hungry vegetative phase to Phosphorous and Potassium heavy flowering stage. Organic fertilizers should not be used in DWC as they can introduce pathogens to the water solution. Microbes should only be introduced via a controlled beneficial microbe tea (optional).
The 1-quart pack will be enough to get you through a single grow if using a single reservoir and 2×2 or 3×3 tent.
The 1-gallon pack should be enough for 4-6x 240 Watt grow cycles or 2-3x 480 Watt grow cycles.
I recommend getting the gallon pack if you can afford it. You will end up needing more down the road. You will likely use 2x as much Bloom as you do Micro or Grow in DWC.
Pro Silicate – Supplementing silicate helps with cell wall strength and increase water uptake and even adds an extra level of protection against fungal diseases like powdery mildew. I strongly recommend it for anyone growing in DWC. Use during vegetative growth at 5mL per gallon. 1-Litre of Pro Silicate will last most micro growers a few years. ArmorSI is a suitable alternative if ProSilicate is not available.
The doc’s nutrient calculator makes it easy to mix up large batches of nutrients at a time. I find that a 250 mL graduated cylinder is the perfect size for measuring out large amount of nutrients. Who wants to measure out 30+ tablespoons for a 15 gallon batch? Not the doc.
This is the General Hydroponics feed chart the above calculator is based on the recommended dosage by General Hydroponics. Some growers prefer to reduce this concentration but I have never had issues running it at full force. If you are growing in a low humidity environment or using outdated HPS lights it is possible that your plants will drink water faster and thus could experience nutrient burn. If you notice any burnt yellow tips on new growth reduce the quantities above by 50%.
General Hydroponics Flora series was first formulated in 1976 according to their website. I cannot confirm this date but the stuff has been around forever. I go through way more of the Bloom (red) than I do the Gro (green) or Micro (brown). This is because in DWC the plants fly through veg. They spend the most time in flower where they drink up the Bloom.
Strength – I almost always mix at 100% strength. They only time I would reduce the strength would be if (1) I see signs of nutrient burn (yellow crispy leaf tips) or (2) for low humidity (50% or less) situations where transpiration is high and the plant is drinking water faster. Most HPS growers need to reduce nutrient strength because the additional heat the bulbs put off increases transpiration.
Brown roots – Do not be scared of slightly brown roots when using General Hydroponics in DWC. Although typically brown roots are an indication of root rot in DWC, the Micro nutrient from the Flora pack has the tendency to colour the roots brown. This is harmless, and if your roots do not show other signs of root rot (like foul smell, falling off or turning black/very dark brown) there is no cause for concern.
Mixing Extra Nutrients in Advance – is something I typically do not recommend because this nutrient solution can foster the growth of bacteria that can lead to problems down the road. If you must mix more than your DWC reservoir holds follow the same rules of DWC growing. Keep the nutrient solution cold (below 60F), no light leaks, and use an airpump/airstone to keep it aerated.
Never Mix the Nutrients Together Without Water – Always add the Micro, Flora and Gro to the water container one at a time. Mixing the different solutions together without the presence of water to dilute them will cause solids to precipitate out. This will make it harder for the nutrients to dissolve into solution. I learned this the hard way when mixing a batch of nutrients into a jar for a friend who was growing outdoors. The result was a brick of ionic salts that was nearly impossible to dissolve.
pH and EC Meter
pH Meter – maintaining pH is crucial for proper nutrient absorption. For DWC your pH needs to remain between 5.5 and 6.5. I like to mix freshwater batches to pH 5.5 because the trend I have noticed is pH rises as plants absorb nutrients. You will need a pH meter to grow any hydroponic plants and it is recommended for soil grows as well.
EC/ppm Meter – An EC meter measures Electrical Conductivity to give you a rough measure of the nutrients in your solution. It is only a rough measure because pH up, pH down, minerals from your tap water and minerals the plants deposit into the water will all increase EC. You can get away with not using an EC meter but they make it much easier to top off your water rather than having to do complete water changes each time.
Baseline EC level – When using the chart above remember to subtract the baseline EC level. For example:
Tap water EC = 150
Measured EC = 1550
Actual EC = 1400
**Always remember to store your pH meter wet!! allowing the electrode to dry out will ruin the meter (ask me how I know, Dr. Meter was kind enough to replace it for me free of charge!) **
Germinate Seeds / Start Clones
The first step to starting your grow is to germinate your seeds (DWC Germination Guide) or acquire clones if you are lucky enough to have access to them. Ideally you should be taking your own clones using a DIY aeroponics cloner. Using clones will shave 2-3 weeks off your grow time and guarantee your plants are female (assuming you clone from a female mother plant). Clones also replicate the phenotype of the parent plant, unlike seeds which can produce of variety of different phenotypes despite all being the same strain. Professional breeders will “pheno hunt” by germinating dozens, even hundreds, of the same strain and selecting for desirable traits. This isn’t viable on a small scale so you’re playing a bit of a lottery with seeds.
If using Rockwool cubes for germination they should always be soaked in pH 5.5 water. Seedlings can be transferred to your DWC reservoir as soon they have visible roots, just make sure the rockwool is partially submerged in the nutrient solution. I.e. during the early stages you will have the water level in your DWC reservoir much higher than normal (90-95% full). Rockwool cubes should always be covered by hydroton, algae will grow on rockwool that is exposed to light.
Feminized seeds are preferred when germinating from seeds. Feminized seeds are created by exposing a mother plant to colloidal silver. This creates offspring that only have female genetic, and are thus guaranteed to be female.
Seeds and clones can both be started using rockwool cubes. Rockwool transitions fairly well to DWC, although it can be a source of algae growth if exposed to light. You can use neoprene collars to clone without rockwool and go straight to hydroton which is my preferred method (see: DIY Cloner Build). Soil is not recommended for starting the plants as the soil is hard to remove from the roots and will pollute your water with debris.
Printed LED boards are typically too strong for propagating clones or seedlings, even at 50% power you’ll want to start at 5’+ distance. A small CFL or LED table lamp works well for getting your plants started. I use A19 LEDs mounted on an 4 bulb fixture for my veg room. Aim for a target VPD between 0.6 and 0.9 for seeds and clones.
Rinse new hydroton well before using. If reusing hydroton from a previous grow it should be boiled for 30 minutes to sterilize the pebbles.
I strongly recommend building a DIY cloner for starting your plants. It works extremely well for both seeds and clones. My cloner is an alternative to “top fed DWC” which is very similar but does not feed the roots as efficiently as spraying them with nutrient solution (i.e. aeroponics).
DIY Aeroponics Cloner
Overview
Cloning with Aeroponics for DWC
A friend of mine that grows for a craft cannabis producer sent me a photo of the aeroponics cloner they use for commercial production. 10 days from cutting he had MASSIVE healthy roots with no rockwool. I had to recreate this at home.
Aeroponics is the process of growing plants in a mist environment. Often cited as the most efficient method of nutrient uptake by NASA experiments that researched growing high protein beans in space. Aeroponics is new to me as DWC has worked so well I have not had to look into atomizing the nutrient solution. If roots can sit in the nutrient solution 24/7 why bother with water pumps and misting nozzles. For mature plants I still believe aeroponics is not necessary. DWC is so much easier.
For clones and seedlings – aeroponics makes sense. I tried cloning in DWC with limited success. The cuttings would get waterlogged and rot away before the roots had a chance to develop.
Low-Pressure VS High-Pressure Aeroponics
Aeroponics can be divided into two categories.
Low Pressure Aeroponics – is usually done with a submersible pump. The water/nutrient solution is sprayed rather than being atomized into a fine mist. You can use a regular garden sprinkler/sprayer or misting nozzles as pictured below.
this would be considered “low pressure” aeroponics
High Pressure Aeroponics – uses 60+ PSI and misting nozzles to create a fine, atomized mist of water/nutrient solution. High-pressure Aeroponics requires a diaphragm pump and accumulator tank to generate the necessary pressure.
This guide focuses on Low-Pressure Aeroponics because it works fine for cloning/propagation and is a much easier & cheaper build.
This method of cloning falls directly in line with my low maintenance philosophy. No need to mist a humidity dome. The foam cuffs are re-useable. There is no rockwool that serves as a home for algae and other pathogens.
If you drill 1 3/4″ holes it will be a perfect tight fit for 2″ collars. Avoid using net cups in the cloner unless you want to deal with untangling the roots out of them later.
Foam Vs Neoprene Collars
If you look for 2″ foam cuffs on amazon you can choose between neoprene and foam. My local hydro store only had neoprene so I ordered some foam online to compare. The foam cuff is much better. It holds no moisture, unlike the neoprene which felt soggy and soft after a few days.
Wire/Airline Routing
The foam collars work well to route the cable out of your bucket. I used to run the cable out of the lid but that made it impossible to remove the lid fully without unplugging the pump. Drill a 1/4″ hole for standard airline tubing.
Pump Timing Cycles
Cloning: 1 minute on, 20 minutes off
Germination: 1 minute on, 60 minutes off
Cloning Temperatures and Humidity
Water Temp: 68-80F (I prefer 68-72F)
Air Temp: 55-80F (ideal range is 70F)
Humidity: 45% – 80% (Yes I have cloned down to 45% humidity with this method, just make sure you remove all fan leaves)
Running the sub-pump on a timer also helps lower water temperatures. Any more than this and I find the sub-pump increases my water temperatures beyond what I consider an acceptable range. People on Reddit have mentioned they like to go up to 80F for cloning but that exponentially increases your risk of infection. I like to keep water temps under 72F.
Modifying the Pump: Misting Nozzles / Sprayer & Filter
Drill appropriately sized holes for the misting nozzles. The drill size for my nozzles was 1/8″.
I use a tea strainer hot glued to my sub-pump to prevent small bits of roots from getting inside the pump and impeding the motor. You can get away without it but it’s a cheap insurance policy to keep the nozzles from clogging. The tea strainer is easy to clean and can be found online for $10.
tea strainer used as filter for sub pump
You could likely save a few bucks by using a sprinkler head rigged up to the sub pump with a small 6″ riser. I went with PVC since I already had some around from my SCROG build.
Don’t forget to put an airstone in your bucket. Although you may think the water is being aerated by the sub-pump, it is not. The system needs fresh oxygen from outside the bucket.
Lightproof Air Exhaust.
The air pump will create positive pressure in the bucket which can create water leaks when the sub-pump kicks on. In a typical DWC reservoir, the hydroton will allow air to escape, so these exhausts are not necessary.
To create an air exhaust drill a hole in the bucket lid and cover it with a flap of double-sided duct tape to prevent light leaks.
LPT: If using a large tote you can just drill a few tiny 1/16″ holes near the top side wall for air exhaust. With small enough holes you will not get any leaking.
Sterilization
Sterilizing the pump, container and foam pucks is very important. Cloning creates an open wound on the plant, making it susceptible to infection. Luckily sterilization is very easy since the pump does all the work for you. Fill the bucket with 1 gallon of Star San solution (6mL of Star San/Gallon) and run the pump for 5 minutes.
Star San is a food-safe non-rinse sanitizer that is commonly used in homebrewing. You don’t need to rinse the remaining foam after sterilization. This is because it is an acid-based sanitizer, so any remaining foam is rendered inert when diluted by water. Dump out as much sanitizer as possible and proceed to the next step.
Unlike soil (which has trace nutrients) cloning/germination in hydroponics requires immediate additions of nutrients. Once you get the pH to 5.5 add:
1.2 mL GH Rapid Start
1 mL of FloraGro
1 mL of FloraMicro
1 mL of FloraBloom
My starting ppm was 100 and the final ppm was around 300.
The result
6 days after cutting roots are starting to show12 days after cutting
This is what we’re going for. Healthy white roots ready to be thrown into a 3″ or 6″ net pot with hydroton.
Scaling It up
I have also scaled this method up without issue. When using tall 10+ gallon totes I have not have any issues with leaking. Just make sure to spray paint the lid black and then white to prevent light leaks, as in the DWC Reservoir tek.
Aeroponics Seed Germination
Seeds can also be germinated using these cloning buckets. Check out my guide on using cloning collars to germinate for DWC.
Black Bucket Vs Painted Bucket
If you can find a black bucket I strongly recommend it. Or at the very least get a black lid. Spray paint likes to chip off the plastic and will find its way into your water. Give your local aquarium supply store a call and see if the have any extra coral salt buckets.
Water Leaks In Aeroponics Cloner
flooding created by sub-pump used with tote
As I was getting ready for work one morning I checked on the ladies to find my plywood grow box was flooded. The pump had slowly sprayed a substantial amount of water out of the tote. The cause of my problem was not having an air exhaust to vent out positive pressure in the cloner. I also now use buckets and deeper totes to reduce the risk of water leaking during the mist cycle.
My Experience using Rockwool with DWC
Rockwool and humidity domes have always been synonymous with cloning plants. Although I have had success with using rockwool, there are a number of problems with it in DWC grows. Rockwool holds water, which can become stale and unoxygenated. Traditional humidity domes run at 100% humidity which is an invitation for mold and bacteria to develop. This mold/bacteria can spread quickly in DWC systems.
Clones that got waterlogged and died in rockwool
Sidebar: Do Not use an ultrasonic fogger for cloning
My first attempt at aeroponics involved the use of a $17 ultrasonic fogger. These are often used in cool mist humidifiers or reptile foggers. An oscillating ceramic plate atomizes water into particles that are 3-5 microns in size.
cuttings that were suffocated by a fogger
The cuttings were killed by the fogger in a matter of 24 hours. Because the mist is so fine it blankets the cuttings, not allowing air to get to them. I had the fogger on a cycle timer running for 3 minutes on and 15 minutes off. I could have tried to introduce air into the box but this would be too much hassle. In addition, I have read that people were having problems with the oscillating plate clogging up and having difficulty atomizing nutrient solutions which have ions 40-50 microns in size. For $17 it was a worthy experiment, but this fogger ended up going back to amazon. Save the ultrasonic misters for the DIY Humidifier build.
I did have a reddit user message me saying that he uses ultrasonic foggers without issue for cloning. His setup seemed similar to mine. If you have any experience using foggers shoot me a message on reddit.
Store Bought Aeroponincs Cloners
There are a number of cloners available for purchase via amazon or your local hydroponics store. Be warned that some of them are DWC cloners, and not true Aeroponics cloners (e.g. Psycloner, Oxyclone). DO NOT BUY THESE. They are overpriced and I have found them to be rather ineffective. The stem sits in water making the chances of getting rot very high.
The only good store bought Aeronponics cloners I have found are:
When starting out your water reservoir should be over-filled to give the small roots access to water. The roots must be submerged, if not the plant will not be getting any water. If you are using a very large reservoir (40 gallon+) it sometimes helps to start the plants in a smaller reservoir.
Use the Nutrient Calculator to mix up a batch of water using the “Mild Vegetative Growth” ratio. Don’t forget to add pH down to bring your water down to pH 5.5. Aim for a target VPD between 0.6- 0.9 during early veg and 0.9 and 1.2 during regular vegetative growth
After the roots are established it is not recommended to fill past the bottom of the net pots.
The light should be dimmed down to 50% power to start. If there is no external dimmer provided with your lights use a small Phillips screwdriver to turn the dimmer down on the LED Driver. The light should be 24-48” above the plant during vegetative growth. Slowly increase the power of the light so that you are up to 100% by the time flowering starts.
Light Burn – is a risk with LED Boards. If the leaves start to curl up on the edges or have a “3D” look you have too much light. If the light is already at 50% and you have no more room to raise it up further a piece of cardboard can be rested on your trellis net to give the plants some shade from the LED as they adapt to the high photon light source. Remember that LED Boards put out some serious light and the high PPFD can easily fry young plants.
In DWC, vegetative growth takes 2-3 weeks on average, much shorter than with soil. The goal of vegetative growth is to get enough growth to reach the corners of your Scrog screen. You do not want to the plants to start growing through the screen. The first 2-3 weeks of flowering will still be vegetative growth anyways. What I mean by this is that day 1 of flower is measured by when you flip your lights from 18-6 to 12-12. The plants do not magically start to flower the same day, so day 1-21 of ‘flower’ or 12-12 light phase are usually aggressive vegetative growth as the plants transition into their flowering phase.
Monitoring VPD
During early vegetative growth it is VERY important to maintain adequate Vapor Pressure Deficit (VPD). To keep VPD low enough to keep the plants from getting stunted I typically use a humidifier set to 60-70% humidity depending on the temperature. As the plants grow they are able to transpire moisture into the air very effectively and I typically switch from a humidifier to a dehumidifier at about week 2-3 of veg or at the start of flower.
I strongly recommend the use of a SensorPush or Pulse system for monitoring VPD and setting alerts to let you know if VPD drifts out of range.
Achieving a Flat Canopy
Once your plants have 5-6+ nodes you can switch the water over to the “Aggressive Vegetative Growth” formula. This is a good time to add potassium silicate. Potassium silicate improves cell wall growth and will make your plants stronger, which is important later in the growing cycle. Potassium silicate is also a natural fungicide that will help your plant fight off infection. Potassium silicate is optional but with how cheap it is I recommend everyone use it.
Training the plants should be done during early vegetative growth when the stalks are still supple. The goal of training is to make a flat bush rather than a tall Christmas tree.
There are two methods that I like to use for maintaining a flat canopy:
Option 1: Topping
Once the plants have approx 5-6 nodes cut the top node off. Be careful to only take off the top node. This will typically cause a Y in the growth with two new nodes growing out as in the picture below. You can sometimes even get 3-4 new nodes coming from a topped location. Topped plants can be topped again a few nodes up helping fill out your screen of green.
Option 2: Super Cropping
Super cropping is a more stressful method of training but can be extremely effective if you forgot to top your plants. Supercropping is done by gently rubbing the stem between two fingers until it is pliable enough to bend at a 90-degree angle. Over time this bend will harden into a rigid knuckle. It is one of my favourite training methods as there is very little work involved.
Supercrop Day 1
Supercrop Day 21
Flowering Phase
Flowering is kick started by switching the light cycle from 18/6 to 12/12. The start of flowering is a good time to do a full water change, drain any remaining water from the DWC tank. Mix up a batch of water using the “Transition to Bloom” ratio and bring the pH down to 5.5. Aim for a target VPD between 1.2 and 1.6 during flower.
Do not “over veg” your plants. As you can see above the plants will grow to 2-3 times their size during the flowering cycle. It is very easy to outgrow your box with how quickly plants grow in DWC!
During the flowering cycle your main job is to trim excessive growth. There are a few methods you should employ.
Lollipoping– is the process of removing all bottom growth from your plants. ‘lollipopping’ can be done early in flower before any pistils have begun.
Larf – is undeveloped leafy bud that has little value. Bottom growth is removed because these bud production areas will not contribute quality buds. They will be immature and consume resources that the plant could otherwise be devoting to producing quality buds at the top of the canopy.
As your plants grow in height long shoots should be bent and woven into the screen. You want as FLAT a canopy as possible to maximize light utilization. You can also have a slight bowl shape to the canopy where colas on the outside are allowed to grow taller while the middle is kept as flat as possible.
Twist ties – are a great tool for training your plants and attaching it to the scrog system.
Strip n Spread – is the process of removing the vast majority of fan leaves once pistil production has begun. Opinions vary on how many fan leaves should be removed but I have seen almost all fan leaves removed and the plants still do fine. The advantage of strip and spread is that you will get thick, dense rock hard nugs and will have much less trimming to do later. I typically only leave 2-3 nodes on the top of each branch and trim everything below that and usually defoliate/trim the plants on day 1 and day 21 of flower.
Fan Leaves – are attached to the plant via a stem. These are the main leaves you want to trim. The plant produces more than is necessary as in the wild bugs and pests will eat away at these. In a controlled indoor environment removing the majority of your fan leaves during flowering helps improve air circulation and plant health. This will seem counterintuitive to new growers but over time you will see how quickly these fan leaves will repopulate, and how well plants do when they are trimmed frequently.
Flushing Plants in DWC
Flushing plants towards the end of the flowering stage is essential for bringing colour and character out of your flowers. In DWC flushing is incredibly simple and effective because you do not have to deal with soil runoff. There remains an ongoing debate concerning whether or not flushing helps produce a smooth burning flower. Some argue that flushing does not actually remove mineral deposits. There is no arguing that flushing brings beautiful purple colours out of strains that have the potential- so I always flush when growing for flower.
When growing for hash rosin I don’t bother with flushing the plants as I have not found it to make a difference in the final product.
When to Flush
2 to 7 days before harvest
Trichomes are predominantly cloudy
Amber trichomes start appearing
Flushing method:
Use sub pump or manually drain nutrient solution from reservoir
Refill tank with tap water and measure EC to determine baseline
After 4-12 hours measure EC again to see how much it has gone up
Drain water as before
Continue this process until the EC stops rising 50-100ppm above your baseline
Harvest
Most breeders give an estimated flowering time for their plants (typically 60-65 days). This is just an estimate and should be used as a general approximation
Plants are ready to harvest:
When 5-10% of the trichomes turn amber (preferred method)
When the plant stops growing new white pistils and the majority of the pistils start to turn brown (not very reliable)
The colours of the bud change such that it looks “ripe” (over time you will develop a feel for when the buds are ready)
Trichomes go from Clear > Cloudy > Amber. It is often said that the more amber trichomes you have the more of a indica “body” high. The more clear trichomes you have the more of sativa “head” style high. This is what I would call stoner science and has not been proven by any studies I can find.
I recommend harvesting the plants when they have 5-10% amber trichomes. If you want more of a Sativa or Indica effect grow the appropriate stain.
To inspect your trichomes you need a 60x magnification glass. I recommend getting one like this that attaches to your phone camera. Not only can you take pictures, your phone camera will stabilize and autofocus for you.
This magnifies the picture on your phone screen and makes it much easier to test samples. I always recommend taking samples on 5 parts of your plants. If at least 2-3 of those samples have amber trichomes in them you are good to harvest. Samples can be taken anywhere there are trichomes. You can remove a sugar leaf for testing or test right on the plant.
This is the ratio of cloudy to amber you are looking for. Mainly cloudy with the odd amber trichome mixed in. If you can recreate this in a few samples your plants are ready.
Heavy amber trichomes in a meat madness plant I let flower 70+ days.
In addition to the items above, I would recommend inviting over some good friends who are willing to be paid in pizza/beer/weed. If that is not available because you’re in a pandemic then cook up a steak, roll a joint, and pour yourself a fresh beer.
Every first grower’s favourite day… ‘Trim Day’. Or as outdoor growers call it ‘Choptober’.
I prefer a combination wet/dry trim. I remove all fan leaves at the time of harvest (wet trim). Leaving sugar leaves on during drying helps protect sensitive trichome heads.
Sugar leaves – are typically covered in trichomes so you may be temped to leave on long pieces. I do not recommend this; they will curl up and look unsightly once drying is complete. Sugar leaves should be trimmed at the stem if easily accessible. If the stem is obscured cut the leaf as close to the stem as possible.
Larf (which is immature/undeveloped bud) and sugar leaves should be saved for making cannabutter or bubble hash. Fan leaves should only be saved if they have visible trichomes, otherwise save yourself time and throw them away.
Your scissors will gunk up with resin during trimming, there is no way around this. Fill up your 500 mL mason jar with 250 mL of Isopropyl alcohol for soaking the trimming sheers. The pro move is having extra scissors to rotate in, after 20 min of soaking the resin will come off effortlessly. Do not use abrasives (e.g. scotch brite) on your scissors as it will damage the non stick coating.
Your final result should look something like this:
Drying/Curing
DO NOT OVER DRY your cannabis. I see new growers over drying their cannabis a lot more frequently than under drying it. Think of good flower you have smoked before. You should need to use a grinder to grind it up properly. If you can grind it by rubbing between your fingers it is too dry.
Relative humidity should be 57-60% in your drying room. If your humidity is lower than 55% hang a wet towel or run a small humidifier in the dry area. In Canada, during the winter, my RH will be as low as 30% with the furnace running. Drying buds this quickly will cause terpenes to volatilize off, destroying much of the flavour you have worked so hard to create. Don’t over dry and don’t dry too quickly! I recommend the use of a humidity controller paired with a humidifier for drying in cold climates or a de-humidifier for humid climates. In Canada I typically only need a humidifier October – April and can get away with my house AC alone in the summer.
Drying Cannabis should take a minimum of 5-8 days depending on the ambient humidity and temperature in your grow room. 60F and 60% RH is a commonly accepted target for drying.
The Snap Test is one way to determine if your cannabis is ready for curing. Try to bend a medium-sized stem. If it bends easily and feels fresh you require more drying time. If it starts to crack but does not break you are ready for curing. If bending a stem causes it to snap completely you may have over-dried your cannabis, you screwed up. Don’t worry it can be rehydrated using 62% Boveda Packs at the cost of some lost terpenes.
There should be a very small amount of airflow in the room to provide fresh air without drying the plants too quickly. Drying rooms should be dark (e.g. windows taped off with garbage bags) to prevent UV damage to the sensitive trichomes.
Handle the plants with care during this stage. Trichome “heads” contain the majority of the plants terpenes and cannabinoids. As shown in the video below trichomes are very brittle and the heads break off very easily. Try to only touch the stems of the plants.
Storage racks and Laundry Drying Racks are my favourite DIY method for hanging cannabis in a dry room. It is easiest to hang individual colas by a small branch left when trimming. Herb Drying racks can also be used as a purpose built solution.
The most simple method of drying is hanging colas from string, but the reality is you won’t always have a V on top of a stem to hang over the string. I recently saw a neat DIY drying method on reddit using coat hangers and binder clips. Credit to user /the_KushLife for this picture. You can see he left the fan leaves on before drying, meaning he will be doing a dry trim as opposed to the wet trim. Both work well. Wet trim is less work while dry trim gets you a cleaner looking final product. I prefer a hybrid of the two, doing a quick one over wet trim and then taking my time on a dry trim for the top colas and extracting the rest into bubble hash.
Once your plants are dry and you’ve done a final dry trim it is time for curing in mason jars. For large harvests or people who like to automate things you may want to look into the Cannabis Auto Cure System. Curing is an essential part of any cannabis that will be smoked as it allows the chlorophyll in the plant matter to break down. Those making flower rosin can skip the curing step.
Add 1 Ounce (~28g) to every 32 oz (1L) mason jar. Use a Kitchen Scale with a high capacity so you can zero the weight of the jar. This will allow you to track yield in your grow journal. Taking notes is essential to becoming a better grower.
The jars should be burped daily for the first two weeks. To burp the jars you open them for 1 – 30 minutes to release gases that build up during the curing process. Gently shake the jars to prevent clumping and promote air flow. After 3 weeks you may notice the smell start to improve/change. After 4 weeks your cannabis is at its peak for combustion.
