Ebb and Flow System of Hydroponics

All about the Ebb and Flow (Flood & Drain) system

Today we go about ebb and flow system of hydroponics. Hello readers!! So today we are back with desired information about another type of hydroponic system. In further paragraphs, we will be enriching you with a complete guide for Ebb and flow system which is also known as flood and drain system of hydroponic gardening. This system is one of the most widely recognized hydroponic systems present around. It is of intermediate level in difficulty not as complex as some other advanced forms of hydroponics, such as the aeroponics, relatively low-cost to set up, and really versatile. These systems are very popular among home hydroponic growers for many reasons in addition to how simple they are for anyone to put up, you can utilize almost any materials you have laying around to build them with, so you don’t have to pay out much money to cultivate plants hydroponically. Also, they can be built to fit in any accessible space, it is well suited for both indoors or outdoors, and there is no boundary to the diverse and creative freedom to design them for your space. Along with being reasonably priced and easy to establish, plants grow very well in flood and drain systems. The flood and drain system works mainly as it sounds, by merely flooding the plant’s root system with nutrient solution only at regular intervals rather than continuously feeding them.

The principle behind Ebb and flow system:

How a hydroponic flood and drain system works is quite simple. The main element of the flood and drain system is the containers in which plants are growing. You can just grow one plant or many plants/containers in series planted in growing trays. There is a timer that controls the water pumping cycle, as you turn on the pump water with the nutrient solution is pumped through tubing from the reservoir up into the main part of the system by using a submersible fountain/pond pump. The nutrient solution continues to fill (flood) the container (grow tray) and soaks the plant’s roots until it reaches the water limit. Usually, an overflow tube is used to set or mark the limit up to which water should be pumped.

As soon as the water flooding the containers reaches the overflow tube height, it streams back down to the reservoir where it is recirculated back through the system again. The overflow tube maintains the water level height in the flood and drains system, and it also makes sure that the nutrient solution dissolved in water doesn’t drip out from the top of the system while the pump is on. While at the set level, there is a constant circulation of nutrient water in the system for a certain period. At this point, the overflow tube is involved in ensuring the maintenance of the standard water level. When the pump is off, the water comes back down into the reservoir through the drainage system. This is how the Ebb and flow system nurtures growing plants efficiently as well as sustainable.

In simple words we can define its basic working as like in other methods, the basic concept is very simple, the growing plants are placed in a grow tray or in the container, which is periodically filled with nutrient enrich water pumped out of a reservoir placed below. The system exploits gravity to revisit the water to the reservoir to be reused.

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What do you need to build a Flood and Drain (Ebb and Flow) system:

Before using it or seeing in action this system may seem complicated to beginners because it involves so many different components, but they all come together quite effortlessly and can be assembled in very little time. Once it is assembled, this system desires modest maintenance and cultivates plants efficiently with very less electricity or water use.

So here the list:

  • Container for growing plants.
  • Container (reservoir) to hold the nutrient solution.
  • Submersible fountain/pond pump.
  • Light timer or digital timer to turn the pump on and off.
  • Some tubing to supply water from the pump in the reservoir to the system to be watered.
  • An overflow tube set to the standard water level height.
  • The Growing medium may be clay pebbles.

Basically, the essence of ebb and flow system is the two main parts of the system – the reservoir, plant tray or container and submersible pump with timer.

The Plant Tray or container

The plant tray is also known as flood tray or container is a large, shallow container or several small ones in a system, in which you raise your plants. Plant your seedlings in perforated pots filled with a growing medium such as vermiculite. Make sure the pots that your seedlings are in must be about twice as deep as the flood tray. The flood tray is pumped full of nutrient-rich water from the reservoir placed below, which flows up through the bottom of the pots to the roots of the plants. The water is then streamed back out, allowing the roots to become dry and oxygenated before flooding again.

The Reservoir

Another necessary part of any hydroponic system is the reservoir. This contains water and nutrients that plants require. Usually, one reservoir is enough for most of the Ebb & Flow systems. If your arrangement is big, the size of the reservoir must also grow respectively, or you need some extra reservoirs to supply an adequate amount of nutrients to the plants. The reservoir is installed directly below the flood tray’s stand. It is connected to the plant tray through a tube for flooding and a drain tube. The fill tube is attached to a submersible pump with a timer, which regulates the flow of water up into the flood tray. The drain tube allows gravity to pull the water in reverse to the reservoir after flooding the tray so that the water can be reused. You can make use of the same water for about a week at a time, after making sure to renew the nutrients every time you refill the water. The submersible pump with a timer allows for a lot of control in this type of system because you can customize the length and frequency of irrigation based on your plants need. 


The purpose of the pipe is to connect the reservoir to the grow trays or container having plants in it in order to facilitate water in and out of the system.

Overflow Tube

One of the USP of flood and drain system, the crucial function of the overflow tube is to set the level of standard height up to which the nutrient solution in the container reaches. The overflow tube also works to ensure that the nutrient solution does not spill out of the reservoir. Because the water can easily overflow because of the pressure build-up during the pumping process.

Growing Media

Because of the technique by which the system works, the growing media for the Ebb & Flow is recommended and must be strong and heavy so that it doesn’t get saggy and floated. Some experienced growers suggest growing materials such as clay gravel, hydroton, perlite, stonewool.

Other Materials

One of the advantages of the flood, drain type of system is that the materials are cheap. There is also a good scope for material improvisation and lots of freedom for creativity. You can use fancy colored tools such as buckets, tubes, water bottle, trashcans, and storage totes. As long as any container can hold water, they are satisfactory for use.

For people who have experience of hydroponic gardening and are little aware of improvisations can use a suitable material like plastic mosquito netting as filters because any place where water stands will need to be filtered.

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Different Types of Ebb and Flow Hydroponics

Varieties of flood and drain system are available and are being used by different growers at home as well as the commercial level that uses the same basic principle of using water pumps to supply plants nutrients solution.

  1. Flooding Tray Design

The flooding table/tray flood and drain (ebb and flow) system type setup is handy when you want to place plants in the system, for the time being, want to be moving them around a lot. Instead of flooding separate containers with plants in it, this technique only floods one container. The structure has a shallow rectangular or a squared tray on top of a raised surface. The reservoir usually sits directly underneath with easy access.  The plants are grown in regular plastic pots or baskets and placed in the flooding tray like regular potted plants filled with growing medium. Once the plants attain stability and maturity, they can be transferred into a permanent hydroponic system.

In the process of flooding nutrients to the plants, one side of the tank lets water in from the pool. Meanwhile, the opposite side enables water to move out from the container back into the nutrient solution reservoir. The duty of the overflow tube is to control the height of water in the container up to which water is filled and can be adjusted as needed.

One limitation of using the flooding tray design is the appearance of algae growth, and to avoid this system has to be cleaned out regularly. Because the top of the tray is usually left open, light is allowed to get into the nutrient solution in the bottom of the tray, facilitates algal growth due to which amount of dissolved oxygen depletes.

  1. Plant containers in series design

This type of setup is most commonly used when you managing the different or large number of plants in different containers at the same time. The work is to get the nutrient flows go through all containers uniformly at set water level, before draining back to the reservoir via the tube. It’s imperative to keep in mind that the system with Flood and drain the containers or grow trays to be flooded need to be placed above the reservoir, like on any stand, table top or bench.

That way the water can stream back to the reservoir effortlessly by gravity, and thus drain the system correctly.

First, multiple containers are all connected together through tubing so that when the system is flooded, they all will flood evenly, and all at the same time. For ease, instead of having separate overflow tubes for each of the containers to be watered, there’s generally only one overflow tube. It is fitted to the system at the base where all the containers are connected to. And when the water height reaches the top of the overflow, it spills over and simply goes back to the reservoir and reused in the system again. The standard height of this one overflow tube will set the height of the water level in all of the connected containers with the plants in them. You can modify the water height in all of the connected containers by simply adjusting the height of the single overflow tube.

Again the system allows you to be as creative as you can with a number of buckets/containers for growing plants of different shape, color, and size.

  1. Serge tank (ebb and flow) system design:

The serge tank type of flood and drain setup is functional when more vertical space is required. normally with flood and drain systems, the reservoir is always lower than container having plants so that the nutrient solution can drain out of the system through gravity back into the reservoir via overflow tube, and when the pump is switched off. Rather than relying on the overflow tube for getting the water evenly in all containers, this design uses a primary tank (called as surge tank) for distributing water uniformly in all containers.

It works on the principle of Flood and drain systems with serge tank in flooding sequence that water seeks its own height. In other words, the water height in one container will be the equivalent to that in another container when they are connected below the water line. The serge tank serves as a provisional reservoir that regulates the water height in all the containers with the growing plants in them and is only full during the irrigation cycle.

As the water level rises in the serge tank, the water level rises equally in all the connected plant containers at the same time. This ebb & flow system functions with a pair of pumps. That means there is one pump placed in the reservoir for moving the nutrient solution into the surge tank and all containers. And another one in the surge tank to push the solution back to the reservoir.

There is a submersible pump inside the surge tank that helps force the nutrient solution back to the reservoir there is a float valve in the surge tank that turns on the pump within it once the water gets the standard level. When the water level gets high enough a pump is turned on in the serge tank. The pump in the serge tank then pumps water back into the main reservoir. At this time both the pumps are on. The serge tank type of flood and drain system costs more to put up because there are many more parts required.

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