Beginner’s Guide to Hydroponic Systems

By: Chris | Last Updated: January 17, 2021

System and lighting selection are the two things most new gardeners get stuck on. There are so many choices, and you want your choice to be perfect from the beginning. One bit of advice I’d love to share is this. It doesn’t matter what you choose, as long as you learn something along the way and have fun doing it!

There’s a lot to cover when it comes to soilless gardening systems, but it doesn’t have to be overly complicated. Instead of pouring over every minuscule detail about every hydroponic system known to the universe, ask yourself these questions.

What kind of budget are you working with?
How much space do you have?
What type of plants are you going to grow?
How much time can you spend maintaining your system?
How handy are you with basic tools?

Answering those simple questions will help you develop a baseline for matching a hydroponic system with your needs. Alright, now that we have that outta the way, let’s take a look at some hydroponic systems!

Before we dive in, I’ll say this upfront. If you want to grow a lot of leafy greens and herbs, pay special attention to the Ebb & Flow, NFT, and Vertical systems. There is a reason why they’re used in commercial growing systems. They’re really efficient.

Hydroponic System Terms

It’s definition time! Don’t worry; it’ll be fun. Understanding these terms will make things easier as you go down the list of hydroponic systems.

Aggregate and Non-Aggregate Hydroponic Systems

Aggregate & Non-Aggregate Systems

As the name implies, aggregate systems use an aggregate or medium to support plants during growth in much the same way soil would. Common aggregate systems include; ebb & flow and wick systems.

Non-aggregate systems use a starter plug, such as rockwool or pool noodles, to support the plant while its roots dangle freely into a nutrient solution. Nutrient Film Technique (NFT) and Kratky method are examples of non-aggregate systems.

Passive & Active Systems

A passive hydroponic system has no moving or motorized parts. Passive systems do not rely on electrical components.

Active hydroponic systems rely on electrical components such as pumps, aerators, and timers to deliver nutrients to plants.

Open & Closed Systems

An open hydroponic system uses a reservoir, a grow chamber, and tubing. The nutrient solution flows from the reservoir to the grow chamber and drains back into the reservoir via tubing. Examples: Nutrient Film Technique, Aeroponics, Ebb & Flow.

In a closed system, the nutrient reservoir serves as both the reservoir and the grow chamber. Plant roots dangle down into the nutrient solution, and no pumps are needed because the solution doesn’t leave the reservoir. Examples: Deep Water Culture (DWC), Kratky method.

Types of Hydroponic Systems

The number of hydroponic systems is debatable, so to be thorough, I’m going to go over 7 of the most popular hydroponic systems in use today. They include:

Kratky Method

System Type: Passive, Non-Aggregate
Build Difficulty: Beginner
Maintenance Difficulty: Low
Cost: Under $50

This system gets its name from the creator, Dr. Bernard Kratky, who originally designed the system for leafy, semi-head, and romaine lettuce production. The most popular adaptation of this system is known as Kratky mason jars.

More info: DIY Kratky Mason Jar

While the Kratky mason jar is a popular kitchen counter sitter, the system can be adapted to much larger applications. For instance, instead of using a mason jar to grow a single plant, you can use a larger container to grow multiple plants at the same time.

The Kratky method is a passive hydroponic system that uses a reservoir sized specifically to hold enough nutrient solution to see a plant through its life-cycle without the need for topping off or refilling.

While most hydroponic systems rely on a pump or aerator to provide oxygen to the roots, the Kratky method works without them. In this system, the plant roots grow at the same rate the nutrient solution is absorbed. As the plant draws down the nutrient solution it develops laterally growing “air roots” that absorb the oxygen above the nutrient solution.

As long as the system does not become contaminated, no maintenance is required while a plant is growing. Kratky method hydroponics is the ultimate “set it and forget it” system. The only maintenance needed will be cleaning before planting, and after harvesting to prepare for the next plant.

The health of a Kratky system revolves around keeping light from contacting the nutrient solution. Make sure you use a non-transparent container. If you use a mason jar, or similar transparent container, use an opaque paint to block light. It’s best to use a black base coat, and then color to your hearts content from there.

You won’t need much space at all for a basic Kratky system. For instance, a one-quart Kratky mason jar takes up only a few inches of countertop and will hold enough nutrient solution to grow a healthy leaf lettuce plant.

If you have a sunny window sill, you’ll only be out the cost of a mason jar, seeds, net pot, seed plug, and paint. For around $50 you’ll have enough supplies to grow almost 100 lettuce plants.

Wick Systems

System Type: Passive, Aggregate
Difficulty: Beginner
Maintenance: Low
Cost: Under $50

Hydroponic wick systems are passive aggregate systems. In a wicking system, a grow bed (or chamber) is filled with a substrate, such as; hydroton, perlite, vermiculite, or sand. The grow bed is placed over the top of a nutrient reservoir. Water-wicking material, such as cotton rope, runs from holes in the bottom of the grow tray down into the reservoir.  The system is “primed” by fully wetting the substrate in the grow tray. As it begins to dry, the wicking material will begin pulling nutrient solution from the reservoir into the grow tray.

Wicking systems can be improved by adding aerator pumps to the reservoir. If pumps are added, this would become an active aggregate system. 

Wick systems are cool because they are a great way to grow things like potatoes and carrots, which are pretty much impossible to grow in a lot of other hydroponic systems.

Deep Water Culture (DWC)

System Type: Active, Non-Aggregate
Build Difficulty: Beginner
Maintenance Difficulty: Low
Cost: $50+

The name deep water culture is a little misleading. What the name actually means is that the roots grow deep into the water. A deep water culture, DWC, system is normally no deeper than a regular reservoir used in any other active system. In fact, a 5-gallon bucket or plastic storage container can be great reservoir choices for your first DWC system.

Cheap Hydroponic Reservoir
These plastic storage containers are great for deep water culture systems

All you need to build a DWC hydroponic system is a reservoir, a lid, net pots, seed starting plugs, seeds, and a decent aerator with large soapstone. The system is very similar to the Kratky method, except that it uses an aerator to oxygenate the water and you’ll be refreshing the solution in the reservoir on a regular basis.

DWC systems are great for beginners and pros alike. They are easy to maintain, inexpensive to build or buy, and they are capable of growing a wide variety of plants. 

Water culture systems are also very tolerant to pump failure. In this system, the root mass is submerged in a nutrient bath, so air pump failure is not as catastrophic as it can be in other systems that rely on water being pumped to the plants.

DWC systems are great, especially if you want to grow denser plants like tomatoes or peppers. Countertop DWC systems are popular for growing herbs.

Ebb & Flow Hydroponic System

Ebb & Flow

System Type: Active, Aggregate
Build Difficulty: Beginner
Maintenance Difficulty: Moderate
Cost: $75+

Ebb & flow systems are active, aggregate systems. Also called flood & drain systems, they are made up of a grow tray (flood tray), a substrate, a reservoir, a pump, tubing, and two fill/drain connectors. The technique is very simple.

The flood tray is filled with the substrate of your choice. I use hydroton expanded clay pebbles because they don’t clog the tubing. If you use a finer substrate, like perlite, you’ll need to place an equally fine mesh screen over the fill and drain ports in the grow tray.

At timed intervals, an electric pump sends water from the reservoir to the flood tray via tubing. The flood tray has one fill line and one drain line. The drain line uses a riser to regulate how high the water fills in the flood tray before entering the drain line. Water fills the tray until it reaches the top of the riser, and then starts draining back into the reservoir. The drain line actually plays two roles. It limits how full the flood tray gets, and as water crests over the riser and begins to drain it crashes back into the reservoir and oxygenates the water in the reservoir.

Ebb & Flow systems are normally operated by a timer. The timer will turn the pump on for 15-30 minutes, 3-4 times per day. Because the substrate in the flood tray is soaked, it provides moisture to the plants throughout the day.

It’s a good idea to keep backup pumps in case of pump failure. One benefit to flood & drain systems is that a pump failure doesn’t immediately threaten plants. I had a pump failure in the past and was able to keep the plants healthy by manually flooding the tray 3-4 times per day, until the replacement pump arrived. Now I make sure to always have at least 1 backup pump nearby.

Ebb & Flow systems normally take up 6-10 square feet, but can be made much larger or smaller.

Nutrient Film Technique (NFT)

System Type: Active, Non-Aggregate
Build Difficulty: Beginner-Intermediate
Maintenance Difficulty: Moderate
Cost: $75+

Nutrient Film Technique (NFT) systems rely on a steady film of nutrient solution circulating through the grow chambers. In this case, film refers to the depth of the solution, which is normally less than 1/4″ deep as it moves through the grow chambers. Plants can be suspended over holes via net cups, or they can be placed directly into the grow chamber.

NFT systems normally consist of multiple grow chambers (PVC pipe, gutters, etc.), an electric pump, tubing, and a nutrient reservoir. Grow chambers are normally positioned at a slight angle to improve nutrient flow. Grow chambers can be interconnected, or fed by separate tubes. Most NFT systems use a collection gutter at the end of the grow chambers that catches runoff, and routes it back to the nutrient reservoir.

Some growers prefer a “hybrid” NFT system that is leveled and has drain lines positioned slightly above the bottom of the grow chamber. This is beneficial because a small amount of nutrient solution will remain trapped in the system if a pump fails. Otherwise, plants in an NFT system can wilt and die quickly if a pump fails and all water is drained from the system. Keep extra pumps handy!

Horizontal NFT systems normally take up approximately 10 square feet but can be adapted to be larger or smaller based on preference. Vertical NFT systems reduce floor space footprint if mounted to a wall. Vertical systems function very similarly, only… you guessed it, it’s vertical.

The biggest consideration when planning an NFT system is pump selection. The pump needs to be capable of supplying nutrient solution to the entire system, without overfilling it. If you’re planning a vertical NFT system, make sure the pump you select has enough “head height” to deliver water to the top of the grow chambers.

If you’re planning to grow a lot of leafy greens and herbs, an NFT system is hard to beat.

Vertical Systems

System Type: Active, Non-Aggregate
Build Difficulty: Beginner-Intermediate
Maintenance Difficulty: Moderate
Cost: $75+

Vertical hydroponic systems can use NFT or aeroponics to deliver the nutrient solution to plants. In a vertical NFT setup, drip lines feed nutrients down the inner walls of the grow chamber. Vertical aeroponic systems use either low pressure or high pressure misters to provide a nutrient solution to plant roots.

Both systems have a collection gutter, or reservoir at the bottom with collects runoff and diverts it back to the main nutrient reservoir for recirculation. These systems require slightly better pumps since the solution will need to be pumped to greater elevation.

In terms of space, vertical systems are the most efficient type of system you can build. A 10 square foot vertical garden will only take up approximately 2 square feet of floor space, plus the size of the reservoir.

Vertical towers normally integrate the reservoir into the base of the tower for an even more compact footprint.

Like their horizontal counterpart, vertical systems are best suited to growing relatively light-weight plants.

Drip Irrigated – Dutch Bucket

System Type: Active, Non-Aggregate
Build Difficulty: Beginner-Intermediate
Maintenance Difficulty: Moderate
Cost: $75+

Dutch bucket, or bato bucket, systems are popular for growing heavier plants like tomatoes and peppers. Dutch bucket systems can take up a lot of space, and are normally used outdoors or in a greenhouse.

Drip irrigation systems use an electric pump, tubing, drip irrigation nozzles, a bucket, a substrate like perlite or hydroton, an overflow drain, a water return channel, and a nutrient reservoir.

Dutch Bucket Diagram

That may sound like a lot of components, but it’s actually a really simple system. The overflow drain is made with a 3-4″ section of 1/2″ PVC pipe, and two 90 degree 1/2″ PVC elbows. A 3/4″ rubber grommet inserted into a 1″ hole in the bucket will keep the overflow drain from leaking.

The return channel can be as simple as a PVC pipe or gutter positioned under the overflow drain. The return channel should be angled slightly downward toward the nutrient reservoir so that overflow from the buckets will return to the reservoir.

Drip line can be made with normal irrigation tubing. An electric pump on a timer will pump water through the drip lines into each bucket, normally for about 30 minutes 3-4 times per day. The overflow drain keeps the substrate in the bucket from becoming overly saturated.

The list keeps going

This guide to hydroponic systems has only scratched the surface, but it covers the most popular hobby systems. Any of these systems will give you a wonderful introduction to hydroponic gardening. The more you learn, the more you’ll want to experiment with, so get ready for that!

As always, if you have any questions or recommendations of ways I can improve this guide please contact me!

Chris Cook started Happy Hydro Farm to share his passion for hydroponic gardening! Growing your own food is incredibly rewarding both physically and mentally. His mantra - "Take excellent care of your plants, and your plants will take excellent care of you."