DIY Deep Water Culture (DWC) System: Step-by-Step Build Guide

July 7, 2025

If you're looking for a clean, compact way to grow plants indoors without soil, building a miniature Deep Water Culture (DWC) system might be exactly what you need. DWC is one of the simplest hydroponic systems out there, and it's great for beginners or anyone working with limited indoor space.

In this guide, we'll walk you through how DWC works, why it's so effective indoors, what plants you can grow, and how we built our own mini DWC system using easy-to-find parts. You'll also find a full material list, step-by-step build instructions, maintenance tips, and troubleshooting guidance based on our real growing experience. If you want to see the build in video form, we have an Instagram Reel you can watch now, and a full-length YouTube tutorial coming soon to our channel.

If you're interested in a system like this but don't want to tackle building the container portion, we've got great news. In the coming weeks, we're aiming to add a new DWC unit to our website. Be sure to sign up for our email list and follow us on Facebook for updates on when it becomes available.

DIY Mini DWC System build with swiss chard plant starts growing hydroponically

Quick Answer: What Is a Mini DWC System?

A mini Deep Water Culture (DWC) system is a small, beginner-friendly hydroponic setup that grows plants without soil. Roots are suspended in a 5-gallon bin of nutrient-rich, oxygenated water, supported by net cups in the lid. An air pump and air stone keep the water aerated so the roots get continuous oxygen. It's one of the easiest hydroponic methods to build, costs around $30 to $160 depending on whether you include lights, and works great for peppers, leafy greens, and herbs grown indoors.

What Is a Deep Water Culture (DWC) System?

A Deep Water Culture system is a type of hydroponic growing method that suspends plant roots in a reservoir filled with nutrient-rich, oxygenated water. Instead of soil, plants sit in net cups supported by the system's lid. Their roots dangle into the solution below, absorbing water and nutrients while an air stone keeps the solution oxygenated.

Research from organizations like NASA, the University of Arizona, and UC Davis indicates that hydroponic and aeroponic systems, where plants receive continuous access to water, nutrients, and oxygen, can lead to faster and healthier growth compared to traditional soil-based methods. We've found this to be true in our own grow tent. Our peppers, chard, and herbs grow faster and produce more in our DWC systems than they ever did in soil pots.

Why Use a Mini DWC System Indoors?

Miniature DWC systems are especially helpful if you're working with limited space. Whether you're growing in a closet, garage, or grow tent, a compact setup can help you make the most of it.

Here are a few reasons we love this system:

Great for apartments, garages, or small grow tents
No soil means less mess indoors
Simple and affordable to build
Perfect for hobby growers or testing new plants
Faster growth with minimal upkeep
Reusable and easy to store

We've used our setup to grow leafy greens, basil, and peppers indoors with great success. At the time of writing this blog, we have Jalapeño Peppers, Long Blend Peppers, Tangerine Peppers, and Banana Peppers all growing in our DIY Miniature DWC Systems. We also have Habanero Peppers growing in the DWC system that we'll soon be offering on our website.

How DWC Compares to Other Hydroponic Systems

On The Grow indoor grow tent setup with hydroponic DWC systems and grow lights

If you're deciding between different hydroponic methods, here's how DWC (Deep Water Culture) stacks up:

Versus Kratky: DWC uses an air pump for continuous oxygenation, making it more reliable for long-term or fruiting plants. Kratky is passive but may require more frequent monitoring as plants mature. Watch video here on TikTok. For a microgreen-specific Kratky walkthrough, check out our complete Kratky method guide.
Versus Aeroponics: DWC keeps roots submerged in nutrient-rich water, making it simpler to manage and more forgiving if something goes wrong. Aeroponics mists roots with nutrients in timed intervals, offering faster growth potential, but it requires more parts, precision, and maintenance. Plus it can leak. Watch our Aeroponics video here on YouTube or read our full DIY aeroponic system build guide.
Versus Aquaponics: DWC uses a simple mix of water, nutrients, and oxygen. No fish or biofiltration required. Aquaponics combines hydroponics with fish-keeping, so while it's sustainable long-term, it requires balancing both plant and fish health, cycling the system, and regular water testing.
Versus NFT (Nutrient Film Technique): DWC is simpler and more stable for beginners. NFT systems require precise flow rates and are better suited for commercial or advanced setups. Watch video here on YouTube.
Versus Ebb & Flow: Ebb & Flow offers more control but involves timers, drainage, and more parts. DWC is easier to build and maintain. Watch video here on YouTube.

A Deep Water Culture system, also known as a DWC system for short, is a great middle-ground. It's active and effective but not overly complicated, which is what makes it so perfect for beginners entering the world of hydroponic growing without being overwhelmed by cost and management, while still getting beautiful results when cared for properly.

Best Plants for Mini DWC Systems

This type of system works best with plants that enjoy steady moisture and nutrients.

Ideal plants include:

Jalapeños, Habaneros, Banana, Sweet peppers and other peppers
Swiss chard, spinach, kale, and lettuce
Tomatoes
Basil, cilantro, mint, and other herbs
Strawberries (on a small scale or for experimenting)

Plants that grow large root systems or need dry periods may not perform well in DWC without system upgrades, or you may need to make a larger version of this system instead of the miniature version. Personally, we like to test the limits of hydroponics, and it's always fun to try out different plants to see what happens.

Light Needs for Indoor Growing

If you're growing indoors, lighting is one of the most important parts of your setup. Without enough light, your plants won't grow well, even if everything else is dialed in.

Leafy greens like lettuce, chard, and spinach do best with 12 to 14 hours of light per day, while fruiting plants like peppers benefit from 14 to 16 hours of consistent light.

We recommend using full-spectrum LED grow lights for the most efficient and effective results. These lights provide the right spectrum for both vegetative growth and flowering, making them ideal for mixed or rotating crops. For a deeper dive on lighting (we focus on microgreens, but the principles apply to most indoor growing), check out our complete lighting guide based on 7 years of testing.

Place your lights close enough to the plant canopy to maximize intensity, but not so close that you risk burning the leaves or developing sunscald on fruit. If you notice leaf tip burn or signs of heat stress, you have a few options:

Lower the shelf or adjust plant height
Trim back the tops of taller plants
Use a dimmable light to reduce output (if available)

Using a timer is also helpful for automating your light cycle and ensuring consistent growth.

Huge swiss chard leaf growing hydroponically in mini DWC system

Lights We're Using in Our Current Setups

We're currently testing two types of grow lights in different grow tents, and both are working extremely well for our DWC systems that have been growing primarily peppers at this time:

Spider Farmer SF1000 Panel Light
We use one light per plant or system, and we love that it's dimmable. This feature gives us more control, especially when growing compact crops or dealing with hot days in the grow tent. We love this one so much that we have 3 of them now, and we highly suggest watching out for their sales. We have our lights spaced from top of the shelf to the bottom of the shelf around 25 to 31 inches for peppers.
Active Grow 54W LED Strip Lights
These have been excellent for even light distribution. While this exact model isn't available anymore, an equivalent option is the Barrina 4FT T8 Plant Grow Light, 252W (6 x 42W): We use two per shelf on an 18" wide grow rack, and the coverage has been great for leafy greens and early-stage peppers. We have our lights spaced from top of the shelf to the bottom of the shelf around 33 inches for peppers.

Jalapeno Peppers under full-spectrum LED grow lights in hydroponic DWC system

Maintaining a Mini DWC System

Once your system is up and running, it's surprisingly hands-off. While there are a few things to look out for, it's all pretty simple, quick, and only occasionally needed.

Here's what we typically monitor:

Water level: Check weekly and top off as needed
Nutrient strength: Re-mix or replenish every 2 to 3 weeks
pH range: Keep between 5.5 and 6.5 for most plants
Water aeration: Ensure your air pump and stones are running properly
Air flow: Ensure you always have a fan pointed towards the plants for mild airflow
Cleanliness: Clean your system between plantings
Water temperature: Keep between 65 to 70°F to maintain oxygen levels and avoid root issues. This is usually really easy when you have your system indoors already.

💡 How often should you change the water completely?
We usually top off weekly and replace all water every 2 to 3 weeks depending on plant size and how much water the plants are drinking. Different plants, and the maturity level of a plant, will determine their water needs. Some drink really slow, and others need more frequent top offs.

Preventing Algae Growth

Algae can be a common issue, especially in new hydroponic setups, and if left unchecked, it can clog roots, reduce oxygen levels, and affect plant health.

Here are a few simple ways to help prevent algae from developing in your DWC system:

Use opaque bins that block light from reaching the water
Cover any exposed gaps around the net cups
Keep your lid closed tightly to limit light penetration
Avoid placing your system near windows or in direct sunlight

Adding clay pebbles or foam inserts around your plants in the net cups can also help block excess light from hitting the nutrient solution. We personally don't always do this, but it's a great thing to know.

If you start noticing algae, it's a sign that light or oxygen balance may be off. You may need to check your air stone placement, light positioning, or even how consistently you're cleaning and maintaining the system. A little algae is common, but if parts of your bin or water appear bright green or slimy, it's time to fully clean and reset the system.

Materials List for Building a DIY Mini DWC System

Now that we've covered what a DWC system is, why it works so well indoors, how it compares to other hydroponic methods, and what types of plants and lighting setups work best, it's time to show you exactly how to build one. Whether you're new to hydroponics or just want a reliable way to grow indoors with minimal effort, this step-by-step build is simple, affordable, and beginner-friendly.

Let's start with the supplies you'll need to put your Mini DWC System together. Please note that your cost may vary depending on where you source supplies. Some of these supplies you'll need to find and source locally yourself, though a lot of it we have linked for you.

Containers & Hardware:

(1) 5-gallon Plastic bin with lid
Electric Drill + 1-inch hole saw
Deburring tool or sandpaper
Net cups
1-inch Rockwool starter cubes

Hydroponic System Supplies:

Air pump
One-way check valve
Airline tubing
Air stones
Liquid hydroponic fertilizer
pH meter + pH up/down solution
Silicone sheet (optional for vibration noise)
Grow light + timer (recommended for indoor use)

Most of these supplies can be found here on our Amazon Affiliate Storefront

Our estimated costs based on local pricing and items from Amazon:

$30.97 without air pump
$70.97 with air pump
$160.97 with the same grow light setup we used
Nutrient refills typically cost $1 to $4 per cycle

💡 Note: If you're concerned about plastic use, we encourage you to do your own research and choose materials you feel comfortable with. We grow for personal use and make choices that suit our needs, but this method may not be right for everyone.

Step-by-Step: How to Build Your Mini DWC System

1. Drill Holes in the Lid

Decide how you want to space your net cups across the lid of your bin, then use a 1-inch hole saw to carefully drill the holes. These openings will hold your net cups, so take your time to get even spacing. Important note: Hole saws can sometimes catch or "grab" the plastic and jump, so work slowly, keep a firm grip, and always wear safety gear.

Next, use a drill bit slightly larger than your airline tubing to create one additional hole near the edge of the lid. This will be where the tubing passes through to connect your air stone.

Once all the holes are drilled, use a deburring tool or sandpaper to smooth out any rough or sharp edges. This is literally the most time-consuming part of the entire build.

Spacing and drilling holes in the DWC bin lid for net cups

2. Clean and Prep

Rinse out your bins and lids thoroughly to remove any plastic shavings, dust, or debris left behind from drilling. Make sure everything is fully dry before moving forward. While it might seem like a small detail, this step is actually pretty important, especially in indoor growing and hydroponics, where sanitation plays a major role in keeping your plants healthy. Starting with clean materials helps prevent common issues like algae, bacteria buildup, and root rot. You can usually tell a lot about someone's system just by how clean and well-maintained it looks throughout the grow cycle.

3. Set Up the Air Pump

This is something that we did not show in our original reel video, because we could not find our box of valves at the time. We plan to do a brand new full-length build video very soon on YouTube, and will include this step in that video.

Cut a short piece of tubing and attach it to the one-way check valve (arrow facing away from the pump). Then:

Connect that tubing to the air pump
Attach a longer tube to the other end of the check valve
Run this tubing through the hole in the bin lid
Connect the air stone to the end that's inside the bin

Place the bin on a reusable silicone grow medium if desired to reduce pump vibration noise.

One-way check valve installed on air pump for hydroponic DWC system

4. Add Net Cups and Growing Medium

Insert the net cups into the holes you drilled in the lid. If you've already started plants in Rockwool cubes and they've reached the point where their first true leaves have emerged, or are even further along, you're ready to place them into the net cups. The cups will hold your plants in place as their roots begin growing down into the aerated water below.

We've personally had great results using Rockwool, but there are other growing mediums out there. Just keep in mind that not all are ideal for hydroponic use. Some come pre-soaked in nutrient solutions or root stimulants, and in our experience, those don't perform as well. We always recommend choosing an inert medium, meaning it contains no added nutrients, and one that retains moisture well to support healthy root development.

Curious how we start our plants for hydroponic systems like this one? Check out this video here.

5. Mix and Add Nutrient Solution

Mix your liquid fertilizer according to the manufacturer's instructions, then adjust the pH to your target range, typically between 5.5 and 6.5 for most plants. Fill each bin with the nutrient solution until the water level sits just below the bottom of the net cups. For our setup, that came out to about 4.4 gallons per bin.

This level allows the water to gently touch the base of the net cups without submerging them completely. It's important to maintain a small gap between the water and the lid to ensure proper oxygen exchange and prevent root suffocation. You should also see a steady stream of bubbles rising up and touching the bottoms of the cups. If you're not seeing bubbles, double-check your air stone and pump. They may not be working correctly.

Want to see exactly what fertilizer we use for our indoor peppers and how we mix it? Check out the video below:

Growth Progress Example: Swiss Chard

Here's a quick visual of our progress after setting up the system:

April 26: System planted
May 3: Noticeable growth
May 10: Peppers and chard doubling in size
May 19: First harvest of Swiss chard and first water refill

Troubleshooting & Tips

Even simple systems can hit a few bumps. Here are some common signs and what they might mean:

Symptom	Possible Cause
Yellowing leaves	Nutrient imbalance or incorrect pH
Slow growth	Weak lighting or water not reaching roots
Drooping plants	Early root rot or low oxygen
Slimy roots	Warm water or insufficient aeration
Algae in the bin	Light reaching the nutrient solution
Brown leaf tips	Nutrient burn or lights too close to canopy

Frequently Asked Questions

How often should I change the water in a mini DWC system?

Top off the water weekly as plants drink it down, and do a full water and nutrient change every 2 to 3 weeks. Plant size, water temperature, and how aggressively the plants are growing will all affect how fast the reservoir drops. Larger, fruiting plants like peppers and tomatoes drink much faster than leafy greens.

What pH should the water be in a DWC system?

Most plants do best between a pH of 5.5 and 6.5. Peppers and tomatoes lean slightly higher (around 6.0 to 6.5), while leafy greens like lettuce and chard do well closer to 5.5 to 6.0. Always check pH after adding nutrients, since the nutrients themselves will shift the pH.

Can you grow microgreens in a DWC system?

Not really, no. Microgreens grow too fast and need a flat surface like a tray, not net cups. For microgreens, we recommend our 7x14 OTG Microgreen Tray Kit or the Kratky method for microgreens, which is a much better hydroponic fit for tray-based growing.

Do I need to use Rockwool, or are there other options?

Rockwool is what we use because it holds moisture well and is completely inert (no added nutrients). Other options include clay pebbles, perlite, or coco coir plugs. The key is to use an inert medium that doesn't come pre-soaked with nutrients or root stimulants, since those can interfere with your hydroponic nutrient solution.

Why is my air pump so loud?

Most cheap air pumps have some vibration noise. Placing the pump on a soft surface (a folded towel, foam pad, or silicone sheet) drastically reduces the noise. Also make sure the pump is sitting flat and not touching any walls or hard surfaces that can amplify vibration.

How long do plants take to grow in a DWC system compared to soil?

In our experience, plants in DWC systems grow noticeably faster than the same plants in soil pots. We've seen peppers and chard reach harvestable size 20 to 30 percent faster, which lines up with what NASA and several university studies have reported about hydroponic versus soil growth rates.

Can I leave my DWC system unattended for a week?

For short trips, yes, as long as your reservoir is topped off, your air pump is on a reliable power source, and your lights are on a timer. The biggest risks during an absence are a power outage (which stops aeration) or the reservoir running dry. For longer trips, have someone check the system midweek.

Healthy white hydroponic jalapeno pepper plant roots in DWC system

Thanks so much for taking the time to read through our DIY Mini DWC System build guide. We hope it gave you the confidence and clarity to try hydroponic growing in your own space. Whether you're growing leafy greens, peppers, or just experimenting with something new, this system is all about learning, having fun, and growing your own food at an affordable cost.

We'll be sharing a full-length video walkthrough of this build soon on our YouTube channel, so be sure to subscribe and stay tuned if you'd like to see the entire process in action.

And just another quick reminder, if you're concerned about plastic containers and materials, this build may not be the right fit for you. We always recommend doing your own research and choosing what feels right for your goals and comfort level. Our system reflects what works for us, but there are plenty of other ways to grow successfully. You're welcome to use a different fertilizer or tweak the setup to suit your own preferences. There are so many great options out there to explore.

Until next time, happy growing!

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Additional Resources

For Microgreens:

Free Downloads:

Free Tray-Specific Downloadable PDF Seeding Guide - Exact seed amounts for dozens of varieties in 10x20 trays
Free Microgreen Troubleshooting, FAQ & Lingo PDF - Comprehensive guide to common issues and microgreen terminology
Free Fertilizer Ratio Guide for Microgreens - Fertilizer dilution and pH ratios for reusable mediums and coco coir

Video Content:
Check out our on-site Video Library, where we've organized hundreds of videos showing the complete growing process for different varieties, tray types, and growing methods.

Comprehensive Course:
Our Microgreen Masterclass Course specifically covers 10x20, Kratky, and large sprouting trays with detailed video walkthroughs for soil, coco coir, and reusable growing mediums.

Related Blog Posts:

Product Recommendations:
All the trays, growing mediums, and supplies mentioned in this guide are available on our website:

Connect With Us:
Follow us on Facebook to see what we're growing, ask questions, and connect with our growing community of microgreen enthusiasts.