Introduction to DWC Hydroponics - "DWC for Dummies" course is in session. 5 gallon buckets and cheap nutrients, lets go!

This came up on the live stoner chat the other day, several guys said they had interest in DWC but was worried it was too complicated.

DWC (Deep Water Culture) is one of the many hydroponic methods. I've also done Kratky. And lots of people have good luck with RDWC, Ebb and Flow, and many others. DWC and Kratky are probably the most straight forward, with the only difference being DWC has the air stone added to add additional oxygen to the water for the roots. The Kratky method relies on not refilling the container fully, and the roots growing "air roots" which absorb oxygen from the moist air. I have grown some monster tomatoes with the kratky method, so it works really well too.

This will be my 5th run of autoflowers using DWC as the grow method, and I'm feeling fairly confident at this point.

So my plan here is, I am growing a Mephisto Sour Orange Diesel Kush (from here on known as SODK).


She is the one in the rockwool cube at the bottom. I sprouted it on a damp paper towel in a ziplock and then moved it to the rockwool when it started growing its little root. However, whatever method works for you is fine, but keep in mind with DWC that cleanliness matters. I have started them in coco coir inside of a net pot, however that coco will keep getting into your nutrient water and its kind of a pain.

Lets talk nutrients.

I will be doing this grow with masterblend nutrients. There are 3 components, the Masterblend nutrient mix, epsom salt, and Calcium Nitrate.

Why masterblend? Because it works and its cheap.
A 25lb kit is $60 on amazon
Amazon product
And will be enough nutrients to keep you growing for years and years.


The easiest thing to do that I have found is to dissolve them in water. It makes working with them easier and they are easier to measure.

One bottle is 240 grams of masterblend formula and 120 grams of epsom salt dissolved into 1 liter of water.
The other bottle is 240 grams of calcium nitrate dissolved into 1 liter of water.

If you have kids around, make sure to put these up, please.

For the "tomato" formula, you would use 10 milliliters of both bottles to one gallon of water. However for autoflowers, we will mix it a little lighter than that. We will be targeting right around 750ppm in our DWC bucket, whicch is around 6ml of each per gallon of water. This will be the same nutrient concentration we keep in the DWC bucket throughout the entire grow.


A few other things we will need.

Kelp Extract is good for young seedlings, it has a lot of hormones and stuff in it that helps them grow quickly.
Some measuring devices. I use the graduated cylinder when I fill whole 5 gallon buckets, and the 10ml syringe when measuring for individual gallons of water.
The 3ml pipette is handy for adding acid because I use exactly 3ml of ph down per gallon of water. However, you will need to figure out how much ph up or down you need to make your water a ph of 6.0. ph of 7 is neutral, however weed likes things a little acidic.

You also need a ph tester. I like to use the drops, they are always accurate and do not need calibrated.
A ppm tester is necessary as well, I just use this cheap yanmik one. It can do ph too, but the calibration goes off after a week or two and its a pain to recalibrate.
You will also need some ph down (and ph up, if you live somewhere with acidic water). I make my own ph down, I go to the auto parts store and buy a quart of battery acid, which is just sulfuric acid. I mix that 1 to 4 with tap water, and thats what I use for ph adjustments. I mix it with water so that you have to use more, which makes it easier to measure out.


<Edit> - Blue Dreamer from a few hours after this was posted, I forgot to include the beneficial bacteria!

Amazon product


I use Southern Ag Garden Friendly Fungicide. Hydroguard is another option, but its more expensive and literally a million times less concentrated. The southern ag stuff is a way better deal, and you only need 8oz, its super duper concentrated. You just add a few ml of this stuff to your DWC bucket and it prevents root rot. You also can add it to a foliar spray and it helps prevent bud rot and other fungal issues, bacilus bacteria produce natural fungicides.

</edit> Ok, back to our regularly scheduled programming...

You need a net cup. I buy these from amazon, its like $10 for 20 of them. I started out using a 2" cup and it was too small and the plant roots seem strangled, and it didn't have enough surface area to support a heavy plant in the top of the bucket, it would pop through the hole and the entire plant will fall down into the bucket. It was a pain. You can also buy DWC bucket lids with integrated cups. But I'm just using harbor freight 5 gallon bucket and lids with a 4" hole cut in the top. Because I'm a cheap ass. You will probably notice that most of what I do is all about using the cheapest materials and nutrients to get the best bang for your buck out of a grow.


You need an air pump. And you need a better one than the cheap ones at walmart. It needs to produce at least 1 liter of air, per gallon of water, per minute.
This one does 1135 liters per hour, or 18 liters per minute. Which is somewhat on the low side for 4 plants in 5 gallons of water each. However, I use this tent for veg growth, and they get moved to another tent with a bigger light and stronger air pump when its flowering time.


This is the DWC bucket, without the net cup in place. Try to avoid white lids. White buckets are fine, but white lids let in too much light. The few I have that are white, I put a layer of duct tape over top of them.

In this tent I just use the smaller air stones since I have a smaller air pump.


However, when the plants are larger and move to the flowering tent, I use 4" dome style air stones and a stronger air pump.


But for a smaller plant without a lot of roots, a regular airstone and pump is fine. But remember, the more air you can get into the water, the more oxygen, and the better your plant can grow. To a point, don't do something crazy and pump pure oxygen into the water or something.

I thought it would be fun to do this how-to as I do a grow, and I can answer any questions anyone may have as we go along. So this thread will take about 4 months until its complete, from today.

My next post will be when the SODK has sprouted, and we move it into the DWC bucket. We will discuss ph'ing the water, adding nutrients, and setting the seedling up in the net cup.
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Will be following along brother :pop:
You can see how much the roots have grown in 6 days.


Today I topped it above the 3rd node, so there will be 3 sets of branches, 6 in total. I will start LST in a week or two when the plant is larger.


I also inoculate weekly with Southern Ag Garden Friendly Fungicide. It is a beneficial bacteria that has anti-fungal properties, so helps prevent bud rot, root rot, and other nasty stuff. Just 3ml in a quart sized spray bottle, and they get a few spritzes a week. Its safe to use when they are in flower as well, as long as there is air movement so they dry quickly.

And yes, I know I sprayed water with the lights on. I have yet to see a plant actually get burnt from water droplets on the leaves.