Ebb and Flow Systems: A Complete Guide

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Ebb and flow system
Author avatar By Parker Curtis
March 29, 2022
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Are you considering a hydroponic setup as an alternative to soil for growing cannabis? If yes, you have to check out the ebb and flow system. It’s an excellent way to keep your setup low-maintenance and maximize plant growth and yields.

Find out what it is, how it works, and why it should be on your radar. Learn how to build a simple ebb and flow hydroponics setup at home or buy one with our highest-quality suggestions.

Pre-veg cannabis in ebb and flow
Pre-veg cannabis in ebb and flow

What is an ebb and flow system?

An ebb and flow hydroponic system, also known as ‘Flood and Drain,’ is a unique setup for hydro growers. Instead of keeping crops constantly submerged, it alternates between dry and wet periods, like an ocean soaking the beach. The system works by flooding your crops with a hydroponic nutrient solution and then letting it drain.

During the former stage, it forces expired air from the roots. The plants get the chance to consume nute-rich water. Then the ebb and flow hydroponics system drains the water and sucks in fresh air to feed the crops with oxygen. You can install the system on the floor or specially-designed growing benches for hydroponic weed.

How does an ebb and flow system work?

Ebb and flow systems come in various designs, but they all rely on the same ‘feast and fast’ principle. That way, this setup teaches your crops to grow strong and make the most of the available nutrition. How does this look in practice?

A plant or flood tray holds perforated pots with your crops. Below the container is a reservoir containing a liquid nutrient solution. A pump pushes the nute-rich water into the tray, where it flows through the pots to the plant roots.

This hydroponic system then drains the water, so the roots dry out and absorb oxygen. A timer triggers the pump to flood the tray again, repeating the process.

Ebb and flow system components

Hydro ebb and flow systems consist of four basic components. Let’s discover what purpose each serves in the overall setup.

Plant tray

The plant tray (flood tray) is a shallow receptacle that holds the cannabis seedlings. The nutrient solution fills this space, letting crops absorb their precious food.

Reservoir

The hydro system reservoir contains a nutrient-rich solution and sits directly below the plant tray. A fill tube and a drain duct connect the tank to the flood container.

Submersible pump

The submersible pump in the reservoir sends the nutrients to the tray according to a timed schedule.

Timer

The timer is an essential component of ebb and flow hydroponic. It controls the frequency and duration of the flood and drain process according to your plants’ needs.

Types of ebb and flow systems

Ebb flow system design changes with the objective, available materials, and space usage. Let’s explore its four main types.

Flooding tray design

Flooding tray is the favored ebb and flow system for growing cannabis. Thanks to its simple design, it’s the go-to for seedlings and herbs that need to move around. This design has only one holding tray, and a reservoir beneath it. The reservoir contains the liquid nutrients and a simple pump.

This ebb and flow grow system pumps water to the tray through one tube. The other tube channels excess liquid. During the draining phase of the ebb and flow system, the pump stops working. Pumping resumes when your timer triggers it.

Series of plant containers

This system consists of several plant containers connected with tubing. As a result, it’s perfect for managing the entire life cycle of your marijuana garden. Although there are individual plant repositories, only one overflow tube controls the water levels.

The ebb and flow system’s reservoir pumps the nutrient solution to flood the containers and drains the excess via the overflow tube. At the preset schedule, the timer gets the process going again.

Surge tank design

This ebb and flow system uses separate plant containers, a surge tank, and an additional pump. The surge tank sits between the reservoir and the individual pot holders.

Instead of directly flooding the containers, this setup pumps the nutrient-rich water from the reservoir into the surge tank first. A timer dictates the frequency of the flood and drain process, while the float valve and pump control water levels.

What makes this ebb flow hydroponic system unique is that all the components are on the same level, saving vertical space and accommodating taller plants.

Dutch bucket design

This hydro system includes a reservoir, several pot holders, a pump, and connecting tubing. Gravity takes care of the excess water, so no overflow tube is necessary.

The pump below the individual containers sends the nutrient solution through an irrigation tube. Liquid nutes drip onto the pots, and surplus liquid flows down to a return pipeline that takes it back to the main tank. In the bucket, crops get nutes 24 hours a day, eliminating the need for regular checkups.

Flowering cannabis in ebb and flow
Flowering cannabis in ebb and flow

What should you consider in your ebb & flow system?

To ensure your ebb and flow works optimally, take note of the following factors.

Grow medium

Consider these two criteria when choosing a suitable grow medium:

  • The ideal grow medium should retain moisture long enough for the roots to feed themselves, but it also needs proper drainage. Lava rock, Rockwool, and hydroton are excellent examples of optimal water retention.
  • A hydroponic ebb and flow system involves constant flooding. For that reason, the medium must be dense enough to sustain the water pressure. If it’s too light, the plant will float and experience root damage.

Flooding schedule

It’s critical to maintain an appropriate flooding frequency in an ebb and flow hydro system.

The schedule depends on the plant size, grow medium, and the climate. You have two goals here— provide the optimum amount of oxygen between cycles and never let the roots dry out.

As a rule of thumb:

  • Watering twice per day is ideal for cooler and more humid environments. Use this if your medium is slow-draining.
  • Flooding three times per day suits warmer locations and fast-draining mediums.
  • Only use a hydroponics ebb and flow cycle four times per day if the weather conditions are very hot and dry.

pH levels

Maintain the pH for cannabis nutrient solution of 5.5–6.5. Nutrient lockout can occur outside this range.

Advantages and disadvantages of ebb and flow system 

As a shining example of hydroponic setups, the ebb and flow system can improve the yield and bud quality. It also has limitations, though.

Let’s explore the strengths and weaknesses of this setup.

Pros

  • Setting up a hydroponic ebb and flow is affordable, and energy costs are low. You also reuse nutrients, avoiding waste.
  • The system requires minimal maintenance since the timer does all the work.
  • Hydro ebb and flow systems accommodate different plant sizes. You can modify them to fit any available area as they don’t take up much space.
  • A flood/drain setup provides cannabis with nutrient-rich water according to a timed schedule. The overflow tube acts as a safety mechanism, ensuring your plants don’t experience nute burn. As a result, your crops enjoy an efficient feeding system.
  • Water temps of an ebb and flow hydro system are easier to manage because of the separate placement of the reservoir. An aquarium chiller or heater can maintain it at the ideal 68–75°F for optimal root development and prevent harmful microbes.

Cons

  • If something goes wrong with the ebb and flow system, the damage might affect all plants. Be sure to check for contaminated water, broken pumps, and clogged overflow pipes.
  • Your crops may face root issues if you don’t establish the system correctly. Mold and nutrient deficiency are the most common side-effects of a subpar setup.

Ebb and flow vs. DWC

The ebb and flow system is a favorite among cultivators, but it’s not the only option. DWC (Deep Water Culture system) is another popular hydro option. Before we compare it to an ebb flow hydro process, here’s how DWC works.

The DWC setup consists of a reservoir, a series of connected buckets, and an air pump. Plants are suspended above the container, and roots remain submerged in the nutrient solution 24/7. 

The air pump supplies oxygen to the reservoir, encouraging maximum absorption of nutrients and accelerating plant growth. This process must function continuously to prevent root damage.

In general, DWC and hydro ebb and flow systems provide the same benefits. Take a closer look, though, and you’ll notice that one has the edge over the other in the following areas.

Hydroponic Cannabis in DWC Bucket
Hydroponic Cannabis in DWC Bucket

Setup

While ebb flow hydro and DWC systems are simple to set up, the former involves more components. Setup is more straightforward with DWC.

Plant growth

As plants in an ebb and flow hydro system go through dry periods during the drain cycle, their roots expand, looking for water and nutrients. Ultimately, ebb and flow crops grow larger than their DWC counterparts, whose roots are constantly submerged.

Water consumption

Although DWC and ebb and flow hydroponic systems reuse water and nutrient solutions, the former uses less water. It utilizes eight 5-gallon buckets, while the size of the latter’s reservoir is 60 gallons. 

Overall, you save at least 20 gallons of water by using DWC.

Changing water

Changing the water is easier in an ebb and flow. You only have to drain and fill one reservoir, while the DWC involves eight individual buckets. 

Danger of root damage

Crops in a DWC system may suffer root damage between feedings because they lack oxygen when the air pump is switched off. Ebb and flow hydro systems strengthen plants during the flood and drain cycles, so they’re more likely to survive.

Consider all these factors before choosing the ideal hydroponic system for you.

Ebb and flow system DIY

You can buy pre-made hydroponic setups, but why waste money?

It’s easy to construct an ebb and flow system DIY. You’ll need the following inexpensive parts:

  • Containers
  • Piping
  • Overflow tube
  • Water pump
  • Reservoir

Here’s how to set up two ebb and flow hydroponic, DIY style.

Container in series

Place your containers on a flat surface to ensure even flooding. Connect them with pipes and add an overflow tube to control the water level during the flood phase.

Attach your system to the reservoir, place your cannabis plants into the containers, and add a nutrient solution to the water. Be sure to plug in the water pump and set up the timer.

Flood tray

The other ebb and flow hydro system design involves placing a tray on an elevated surface, leaving room below it for the reservoir. Hook the tray up with a drain tube to avoid excess water.

Attach a tube to the submersible pump in the reservoir to supply the liquid nutrients to the tray. Connect a timer to start and stop the flood and drain cycle automatically.

Ebb and flow system
Ebb and flow system

The 4 best ebb and flow systems on the market

If you prefer a non-DIY option and want to purchase the best ebb and flow system, here are four brands to consider.

1. Flood tray design

1.1. Viagrow Flood & Drain Kit

Among the most straightforward and efficient ebb and flow hydro systems on the market is the Viagrow Flood and Drain Kit. 

It delivers the ideal quantity of air, nutrients, and water, boosting your plants’ growth rate. Although smaller than competitors, it can efficiently accommodate ten plants.

The ebb flow hydro kit comes with a flooding tray, reservoir, 15 one-gallon nursery pots, a 50-liter bag of Viastone grow rocks, timer, and submersible pump.

1.2. Platinium Ebb & Flow

The Platinium Ebb & Flow setup is less than 11 inches tall, making it the most compact hydroponic system for use in small spaces. It provides an ideal water to air ratio. Its deep table design can fit air pots, Rockwool, or pots.

2. Surge tank design

2.1. Flo-n-Gro Ebb & Flow System – 12 Site

This ebb and flow system is perfect for bigger crops. The Flo-n-Gro comes with a dozen 4-gallon containers, a 55-gallon food-grade reservoir, and twelve 3-gallon 360-degree mesh aeration inserts. 

The containers can accommodate medium-sized sativa because they have a capacity of up to 125 liters of grow media. The Flo-n-GroTitan Controls Oceanus 1, a specialized surge tank, controls the ebb and flow hydro system.

2.2. Big Boy Ebb & Flow Hydroponic System

The Big Boy Ebb & Flow Hydroponic setup has unique RhizoCore bucket lids that enable nutrient solutions and oxygen to flow freely to the roots. Although the system contains only six growing buckets, you can expand it to 12 or even 18 pot sites.

FAQs

Do you need quick information about ebb and flow hydroponic systems? Here are the answers.

How often should you water ebb and flow?

The ebb and flow hydro system flooding schedule depends on many factors, including plant size, grow medium, and climate. The main requirement is not to let the roots dry out. Monitor your crops and adjust the frequency accordingly.

What is the best growing medium for ebb and flow?

The best medium for this system should drain well but not too quickly. The roots should get access to adequate amounts of nutrients after draining, but they shouldn’t stay moist enough to draw mold and bacteria. Rockwool, hydroton, and lava rock fit the bill.

How do you grow with ebb and flow?

With ebb and flow hydroponic systems, you feed your plants by flooding them with a nutrient solution, then starve them during the drain period. The repeated cycle trains their metabolism to work faster, speeding up growth.

Hydroponic beds of cannabis seedlings
Hydroponic cannabis seedling in ebb and flow system

Is an ebb and flow system for you?

As hydroponic setups grow in popularity, many cultivators are moving away from the traditional soil growing style. If you’re looking for a change, an ebb and flow system is a perfect choice to get you started on hydro.

If you’re up for the challenge, get quality cannabis seeds to test your new setup. Subscribe to our newsletter for the latest marijuana news.


About the author: Parker Curtis

Parker Curtis has around a decade of cannabis-growing experience, specialising in soil-less and hydro grows. He’s mastering outdoor, greenhouse, and indoor grows.