This is a DWC tutorial guide aimed at deep water culture for beginners. I will show you how to build and grow in a DWC system from clone to harvest.
Hydroponics literally means working water in latin. Deep water culture is probably the purest form of hydroponics. With DWC the water does all the work because the roots are continually submersed in it. This is different from aeroponics, flood and drain or NFT where the roots are only partially submerged or intermittently wet at intervals.
DWC lends itself well to DIY hydroponics because in its simplest form all you need is a bucket, net pot and air stone. It is inexpensive to build and can give great results that will easily surpass growing in soil or even coco, which in itself is considered a hydroponic medium.
RDWC or recirculating deep water culture is a variation where nutrients are circulated through multiple buckets using a central reservoir. It is more complicated to build but still a very doable DIY project. If you have 2 left thumbs there are many prebuilt hydro systems available ranging from under $100 for small home grows to thousands of dollars for commercial RDWC units like the Current Culture.
I have grown in many different systems over the years from aeroponics, to coco, to flood and drain, and also top feed drip in hydroton. I have never grown in DWC although I have wanted to for some time but I do like to experiment and try new things. So in a way I will be learning along with you.
DWC Tutorial Intro Video
I want cover the advantages and disadvantages of deep water culture first.Then I will be covering how to build an inexpensive and simple RDWC system. I will cover how to clone, veg and flower in DWC. Finally I will be showing and sharing my harvest.
Deep Water Culture For Beginners – The Advantages
Before you get too far along in this DWC tutorial you will want to know what the advantages and also the disadvantages of growing in a DWC system. So first the good:
- Plants grow faster and bigger in DWC
So first and foremost your plants will get bigger and grow faster in deep water culture. Vegging is necessary but it cost more to run the extra lighting and it takes valuable time when you could be flowering instead.
You can cut your veg time in half and get better yields in DWC. Please understand that although plants in hydro may finish slightly faster than those in soil this method will not shorten your flowering time.
- Over watering is a thing of the past
Most problems growers run into are the result of over watering or over feeding. This is especially true for newer growers.
In fact I would guess 90% of all grow room problems come from one of these 2 issues. This is not a problem in DWC or RDWC because plants are submersed in water continually.
- Use lower nutrient levels
Because the roots are growing in nutrient rich water they have everything they need. Energy can go into plant growth instead of foraging for water and nutrients.
Since there is no buffer like in soil or coco everything is readily available. This means you need much lower nutrient levels to grow your plants.
- No grow media to buy
You will not have to buy bags of soil or coco and you wont need to dispose of used soil. Instead you will use a small amount of hydroton in a net pot to give the roots something to anchor to. And it is totally reusable.
- Great for low plant count states
Some states have low plant counts and this system is ideal for that situation. In addition it is much easier to raise a few large plants than dozens of small ones.
Deep Water Culture For Beginners – The Disadvantages
Like any grow system DWC has its quirks too. There are 2 main factors that a grower must be aware of to grow successfully.
- Nutrient Lockout And PH Control
Because plants are growing in a nutrient solution there are no buffers like in soil or coco. This means everything happens fast. Good and bad. Plants grow faster and everything is accelerated. This means things can go south in a hurry too.
If the pH gets to far out of whack nutrient lockout can occur and plants will suffer. Nutrient lockout refers to a situation where plants can not take up needed nutrients because of a pH imbalance even though they are available.
Therefore it is critical to maintain proper pH so nutrients are available to the plants. Generally 5.5 and 6.5 is the recommended range with the higher pH range more suitable for veg. The sweet spot is 5.8 but a range of 5.6 – 6.0 will work best in flower.
Lockout can also occur by over fertilizing. Some nutrients can interfere with uptake of others. Because water is the medium we dont have any buffering and dont need the same level of nutrients we would use in soil or coco. Typically plants in veg are fed about 300 PPMs and the level is raised to 600 in flower. Some growers may raise it to 7-800 for the last few weeks of flower.
Nutrient lockout is totally preventable by monitoring your pH and PPMs. I have a in my reservoir to monitor my pH, PPMs, and water temperature. Alternately you can buy a TDS meter and pH pen to test.
Dont even think about growing in DWC without these!
- Pythium Root Rot
Pythium root rot is the bane of hydro growers everywhere. It can also affect soil grown plants but it is particularly bad in RDWC because it spreads from plant to plant. Pythium is a water borne fungus that causes slimy roots and it can kill your plants.
It grows best in warm water over 72 degrees with low oxygen levels. This is why DWC water temp control is so important for a succesful grow, and why many growers use a chiller to keep water temperatures down. It in an anaerobic organism and likes low oxygen levels and stagnant water so using airstones and providing good water circulation is important to keep it away.
As with many diseases the best cure is prevention. Here is an article on preventing pythium in cannabis. If your can keep temps in the ideal 65°F – 68°F range with sufficient aeration it will be hard for pythium to grow.
This temperature range provides for maximum oxygen saturation so you will need some form of aeration. Traditionally this has been done with an air pump and air stones. Research shows flooming(turning a pump upward to stir the water surface) and waterfalls can be just as effective and much quieter.
It is common practice to add chlorine to the water to keep it sterile and prevent the growth of pythium. is dry concentrated calcium hypochlorite and is used to run a sterile reservoir.
There are 2 schools of thought on preventing pythium. One involves using beneficial bacteria to keep pythium at bay and the other involves chlorine or hydrogen peroxide to keep the water sterile. Growers on both sides of this debate say their system works and prevents pythium.
Personally I prefer keeping a sterile reservoir simply because the bacteria used are really meant for soil and other organics and not water and so they dont have anywhere to really colonize and grow. I believe controlling water temperature is the more important factor.
Finally make sure you can control your water temperature. This may involve moving your reservoir outside your grow area where it is cooler or it may involve adding a chiller.
Dont think about growing in DWC unless you can control water temps and add oxygenation!
DWC Tutorial – How To Build A DWC Hydroponic System
This part of my DWC tutorial will show you how to build an easy recirculating dwc bucket system.
DWC BUCKET BUILD
This is what I call a reverse flow DWC system. It can be built with or without air stones or air pumps if you provide oxygenation with flooming or water falls. I came up with this idea of feeding nutrients from the bottom up several years ago.
I noticed growers were having problems with roots getting sucked into the returns and clogging the system. The obvious solution was to reverse the flow so roots were not being continually sucked downward. Later I found out about slucket buckets that use the same reverse flow principal but otherwise are very much like Current Culture units.
Here is a conversation from my Instagram account I had with them:
I commend you on your creativeness @howtogrowweed420 but, I would argue that your DIY system is not like the Posiflow RDWC system. We pride ourself on a unique system unlike CC system or any other and I think the content on our page showing customer results will attest to that. Again, I think what you’re doing (growing and spreading knowledge) is great but I don’t want any one to have any misunderstanding about the product(s) we offer. Happy growing always. 💚
@slucketbuckets Your system is more complex and I admit they are not the same but both bring water in from the bottom and out the top which is where they are similar. I think unlike CC and most other RDWC systems this reverse flow or positive flow as you call it is the better way to go. I have no doubt your system works great. I actually thought this out before I even knew you existed. My goal is to share knowledge and make a simple system using this principal that home growers can easily build and afford. If I had a commercial space I would probably buy your system but it is really too large for a grow tent. 👍
These units are expensive and designed mainly for commercial use. I wanted something similar but they take up more space than most small growers have, myself included. So I set out to build a smaller less expensive version. I did not copy their idea, indeed I did not even know they existed until later. Let me be clear my design uses the same reverse flow although they call it posiflow. But it is not a slucket bucket system like theirs.
How To Build My DIY “Slucket Bucket”
I have made a hard decision not to grow in DWC for a while. Spring is here and temperatures will be rising. Unfortunately that means water temperatures too. My power is maxed out right now so adding a chiller is not an option at this time.
Timing was bad on my part because I had a bunch of plants that were in growstones and they needed to be flowered too. I wish I had more space but it is what it is.
So I will have to resume my DWC tutorial again in the fall. The GG4 was repotted in growstones and will be flowered soon so no plants suffered. But rest assured this system does work and it can work with or without air stones.
Probably if you are just starting in hydro it will be easier to use air stones to begin with. It is just one less thing to worry about providing you can live with the noise an air pump makes.
I would also recommend trying a single bucket to start. I will be putting together a product list of things needed for this build.