DWC hydroponics for beginners (A DIY Guide)

When it comes to Deep Water Culture (DWC) hydroponics for beginners my first piece of advice is always to just get started.

And when I say get started I mean get started as in DIY. You will learn a lot when you build your first very own DWC hydroponic grow system.

My second piece of advice is to keep it simple at first.

DWC systems come in all kinds of different shapes and forms. I like to divide them into 3 separate groups

  1. DWC system
  2. Hydroponic DWC hydro system with air pump
  3. Using Styrofoam to build a DWC hydro float system

DWC hydroponics – with or without an air pump

The simplest DWC system does not use an air pump.

Deep Water Culture (DWC) beginner setup with no extra air
Allowing space for part of the root system to hang in free air

Instead we allow some space or clearance between the roots and the surface of the water and nutrient solution.

This space is designed to help aerate the roots.

The DWC hydro system adds an air pump and an airstone to your DWC .

You also raise the level of the water and nutrient solution all the way up to the pots.

Apart from this detail. No difference.

And then there is the DWC hydro float system. The only difference from the DWC system with an air pump is that we mount our pots in floating Styrofoam that sits on top of the water and nutrient solution.

And there you have it.

It is basically one and the same setup with small variations.

First step in building a DIY hydroponic DWC

The first step is to actually start building. Your focus should be to get going. And to understand the principles in a hands-on kind of way.

You can read and watch videos about hydroponics until you are blue in the face. But you will learn more and definitely have more fun if you actually get started.

My advice? Build it. And then watch the seeds germinate. You can always add to your setup as needed later on. And trust me, you will. 

When you have that first DWC system up and running you will be better suited to make the decisions about what you need.

The list below contains 2 items that are optional, 1 item that is necessary and 1 item that is necessary but you are likely to already own

  • air pump (optional)
  • airstone (optional)
  • light source (use what you already have)
  • liquid nutrient (necessary later in the process)

To summarize, there is absolutely no reason to start buying before you know what you need. 

What you will need will depend on the size of your DWC system and your level of ambition.

 Fact: Air Pump and airstone are optional in DWC hydroponics

Lettuce seeds germinating in net pot using DWC hydroponic grow system
Lettuce seeds germinating after 3 days

You do not need an air pump and airstone to germinate your seeds in your first DIY hydroponic grow system.

And the same goes for extra lighting and liquid nutrients. They are not needed to germinate your seeds.

So start slow. 

As you can see in the photo seeds geminate just fine in the DWC setup we are building here today.

And there is always time to add to your setup 

This is also why we in this article will focus on how to build a DWC system ideal for the beginner just starting out. It’s a system that you can adapt and add to as needed going forward.

Because as you get started, you are likely to want more.

Build your DWC hydroponics for beginners system

Step 1: Materials and components needed

The DWC hydroponic system we will build will serve as a great base for any modifications you wish to do later.

Materials needed for a DIY hydroponic DWC
Building a DWC hydroponic system at home

I still today use DWC systems I made a long time ago that were built following these steps. 

To build your own DWC hydroponics system you will need:

1. Container with lid
I use plastic storage containers with a lid made from food safe plastic.

In the images you will notice that the plastic container I use is transparent or clear.

I use this type of plastic to show what it looks like. Ideally you want a plastic that will not let through light.

Later on you will add nutrients to the water to feed the plants’ root systems. If you have translucent or clear plastic containers you will have algae buildups. Using plastic containers that block the light will help alleviate this problem.

If translucent plastic is your only available option you can of course cover the container to block the light.

2. Growing medium 
You can use rockwool, stonewool, coconut fibre (coir) or LECA pellets (Hydroton) like I do.

Do however make sure that you wash the LECA before use. It may look clean and feel clean but trust me it needs to be washed before use.

3. Tools for making holes in lid and plastic starter pots
I use a pair of sharp scissors to make holes in the plastic starter pots and the lid of the container.

Using LECA or Hydroton as medium
LECA pellets as medium

Depending on the type of plastic material you buy you may need to drill or use a saw.

Whatever tool you use to take care no to hurt you or anyone else. And if you drill holes, fix the plastic lid onto a solid piece of wood. The wood will prevent the drill from tearing the plastic as you drill through.

4. Seeds, water and plastic film or cover
I recommend you start with seeds with a high germination rate. Ideal choices are lettuce, rocket or basil seeds.

You also need a translucent plastic lid or plastic film to cover the seeds as they are placed in the pots. It is not absolutely necessary but will speed up germination and secure a moist growing environment for the seeds.

Finally, you will need water. And yes, tap water will work just fine. There is no reason to obsess about pH and EC levels at this point. 

Remember, the number one goal is to get started and to start learning while doing.

Step 2: Make holes in the plastic lid

The plastic pots will be fitted in the lid of the container.

To fit the pots into the lid, start in one corner of the lid. Using a marking pen, draw around the pot. Make the square smaller than the top of the plastic starter pot. This way the pot will be suspended in the lid and not fall all the way through the hole you cut.

Continue marking holes across the lid where all your pots will be fitted.

Do not space the holes too close together. You need to give your plants room to grow and develop. 

And remember, if you place the pots too close it automatically means that the root systems will be close together under the lid as well.

Give your plants room to grow.

I recommend spacing the holes roughly 10-15 centimeters (4-6 inches) apart.

When the holes are marked and spaced somewhat evenly I use a pair of scissors to make the holes. When you have cut the first hole, test the size of the opening by placing one of your pots in the whole. It should be held in place, and not fall all the way through the hole. 

Making holes in the container lid is often the hardest part of the whole process. I have been known to space the work out over a couple of days when making larger DWC systems.

Step 3: Turn plastic pots into net pots

Most people buy net pots. I do not. I make my own.

It saves me money but also puts all the starter pots that I have accumulated over the years to good use. 

If you do use old plastic pots you need to wash them properly before use. I never boil plastic but I always give the pots a good clean before using them.

I use sharp nail scissors to turn my pots into net pots. The first couple of pots is often a bit tricky but after a while you get into the flow and it is actually quite easy and therapeutic.

You do need to make quite a few holes in the plastic pots. However, do take care to make the holes long but not too wide. 

Remember, the net pots need to hold the LECA so the holes cannot be too big.

Step 4: Prepare the LECA (Hydroton) pebbles

The LECA (Hydroton) pebbles may look and feel clean to the touch but they need to be washed.

Wash or rinse the LECA until the water is clear.

And yes, it more often than not takes several times to get them clean.

Step 5: Fill the container with water and place the lid on top

Fill DWC container with water
Using tap water fo fill DWC

Fill your container with water leaving about 3 centimeters (1 inch) of space at the top.

The containers I use hold 34 liters (9 gallons) of water. This means that they are heavy to carry around when they are full.

Keep this in mind when you fill your container. 

When the container is full, place your lid on top of the container.

Step 6: Put net pots in place and add LECA

With the lid in place we start filling the net pots with LECA pellets.

Make sure to choose LECA pellets that are large enough to be held by the net pot. This is also why we do this before placing the net pots in the lid.

When the first net pot is about ¾ full insert it in the hold in the lid. 

The water level should be just below the top surface of the LECA. You are looking for all LECA pellets to be in contact with water. But you do not want the top layer of LECA pellets to be completely submerged.

When you have found the level you move on to filling the other net pots with LECA and also putting them in place.

Step 7: Planting the seeds

I should say placing rather than planting as the seeds are carefully placed on the LECA pebbles.

Depending on the size of your net pot, place anything from 5-10 seeds per pot.

At this stage there is always a risk that smaller seeds fall through. Do not worry too much about it at this stage.

You can always replace the water later when the seeds have germinated and you start to see the first leaves.

Step 8: Cover the net pots and keep moist

When the seeds are planted you cover the net pots with a translucent lid or plastic film.

You do not want the environment to be airtight. Air needs to be able to circulate. You are simply creating a greenhouse effect to help the seeds germinate and develop.

Step 9: Adding nutrition to help seedlings develop

When you see true leaves and signs of developing root systems it is time to add liquid nutrition or fertiliser.

Follow the instructions on the packaging and you will soon learn how a little goes a long way.

Do not add too much to “be kind”. Simply follow the instructions. They are there for a reason.

Step 10: Adding extra oxygen to your plants

When the root systems touch the water and nutrient solution in the container you need to give the plant access to oxygen.

DWC grow system with air pump and airstone
Adding air pump and airstone to DWC

The easy solution is to buy an air pump and an airstone and to simply aerate the whole DWC system. Much like how fish tanks are oxygenated.

The other solution is to make sure that there is a space between the top of the container and the water level where the roots can hang in “mid air”.

This is a somewhat trickier setup as there are more things that can go wrong. 

With an air pump connected to an airstone you are basically throwing oxygen at the root system and it is hard to go wrong.

But both setups work. And remember, the truck is to get started.

It should however be mentioned that a basic air pump and airstone should cost you less than $20 and will last you a long time.

But it is your call.

Taking care of you DWC and harvesting

Harvesting your plants follows the same general principles as growing outdoors. There are no specific hydroponics rules to follow.

But what about looking after the system?

The main rule to follow is to keep your water and nutrient solution clean. I recommend replacing the water every 2-3 weeks.

Apart from this there really is not much to do. 

Follow the development of your plants and welcome back to NordicLavender should you have questions going forward.

Frequently asked questions

Meet the author: Mattias is an experienced gardener spending most of his free time on his knees among herbs, plants and garden vegetables. For the past two years he has been sharing gardening projects and how-to tutorials on the NordicLavender website and YouTube channel.