The Ebb and Flow technique also known as Flow and Drain, is one of the most popular hydroponic methods for growing marijuana due to its ease to use, low maintenance and has a high-yield. The technique involves growing a plant in a growing medium where it will produce its stem and as well as roots. After that the roots will develop passing through the growing medium and down to the nutrient water solution.

The bottom level of the growing medium is stuffed with nutrient mixture by using a small pump that’s set on a timer that will nourish and water the plants. When you turn off the timer, the pump and the nutrient solution will sewer back into the water container.

Essentially an Ebb and Flow setup made for cannabis growing will have the individual cannabis plants and pots set up in Rockwool cubes. If you are not fan of using rockwool cubes you can use any other hydroponic growing medium on growing bed. Usually the growing bed will only be able to grip about 2 inches / 5 cm of hydroponic nutrient solution.

The hydroponic nutrient solution will then be pumped onto the growing bed and used to flood the growing medium from the bottom upwardly while in the same time pushing out oxygen.When the nutrient solution reaches its highest level the drain pipe will be stuffed. With that being said if you want to have your own Ebb and Flow system, here is a simple guide on how to build it.

All the materials used in this guide are easy to find online or locally from hydroponic shops. You can buy them separately or if you want to save time, you can buy them as a unit which already has all the components.

Let’s Begin With All The Stuff You Will Need

Reservoir – That’s where you will place the hydroponic nutrient solution. As a rule of thumb i would recommend checking the pH levels at least once a day to avoid any issues, keep it clean and always disinfect.

Gardening Tray – The gardening tray, usually a plastic container is where you will have to place the growing medium and grow the marijuana seedlings. The plastic container is highly recommended to be made up of durable heavy plastic. In order to avoid rotting of the roots, always make sure that there are no small pools or puddles of water when you drain the tray.

Overflow Drain – The overflow drain is used to prevent too much hydroponic nutrient solution flooding in your marijuana plants. For that reason, the drain is placed at the highest area where you want the nutrient solution level to rise.

Table / Support Structure – This is where you will place the gardening tray. To avoid any issues, make sure the support structure is sturdy and able to support the weight of all your plants, gardening tray with nutrient solution and the growing medium. You can use any type of support structure but i find heavy duty metal tables either custom made or found online to work best.

Pipe and Fittings – The pipe is used as a passageway of the nutrient solution from the reservoir tray to the growing tray.

Pump and a Timer – The timer is used to turn the pump on and off on a schedule.

Growing Medium – Choosing which growing medium you are going to use is up to you but one of the most commonly used grow mediums when growing marijuana is Rockwool cubes.

Buckets or Modules – An excellent alternative to the gardening tray is to use modules or buckets where you will have to place the plants separately from each other. One of the advantages of using buckets is that you can easily increase the numbers of marijuana plants.

As a side note i would like to mention that this setup is just an example and there are a lot of other Ebb and Flow systems you can use and have a great success.

How To Assemble

Start with installing the overflow drain and pipe to the gardening tray. Now place the gardening tray on the support structure or table depending on what you have. Proceed with placing the reservoir under the gardening tray, put the pump into the reservoir and attach it to the pipe on the grow tray. At the end, connect the timer to the pump.

To make sure that the overflow drain works, make sure there are no leaks in your tubing or pipe.

How To Operate The System

First start with setting the timer in according to the number of marijuana plants you’re growing to flood the roots of your plants around 3 to 4 times per day at regular intervals. As an example, you can flood your plants for 20 minutes. Also make sure you replace the hydroponic nutrient solution every 1 to 2 weeks depending on the marijuana plants you have.

To prevent nutrient lockout due to a high or low pH levels, you will have to make sure that the pH of the nutrient solution stays in the range of 5.5 to 6.5, ideally a pH of 5.8 is your goal. In order to have even distribution of nutrient solution in the gardening tray, you will have to flood it to about 1/2 to 3/4 of its height.

Make sure that you leave at least 20-25% extra nutrient solution left in the reservoir after you flood the grow tray. That’s being done to ensure that there is always enough nutrient solution during the daily evaporation.

What Are The Different Growing Mediums?

Mediums like gravel, sand, perlite and volcanic rock have been getting popular in the hydroponic world. But with the increasing popularity of growing mediums, new substrates have come out on the market. Some of them being rockwool, coco coir and clay pebbles.

Rockwool

Rockwool (Aff.link) is an excellent insulating material and widely used in hydroponic systems and as mentioned above it’s the primarly used growing medium for growing marijuana. However it will take some time and experience to get everything set up and running. Before you place the marijuana seed to germinate, you have to make sure that the pH of the rockwool cube is around 5.5.

In order to do that, immerse the rockwool cubes for 24 hours in the nutrient solution with a pH of around 4.5 and an EC with nutritional value of 0.5 to 0.6. If the pH of the rockwool cubes is still not as the required value, proceed with immersing the cubes again for a few more hours and checking regularly until the pH is 5.5.

Clay Pebbles

When we talk about hydroponics, clay pebbles is probably one of the most popular growing medium used in hydroponic systems nowadays. They are widely known for their ability to provide the roots with excellent oxygenation. By doing that the roots tend to grow amazingly if it’s properly irrigated. Another advantage of clay pebbles is that they don’t place the roots under any stress and allow them to grow easily, allowing easy nutrient absorption by the roots.

Stay away from buying the cheapest ones and make sure you find clay pebbles that are already washed and have their pH adjusted.

Coco Coir

This particular growing medium is extremely popular amongst Asian grow operations. Coco Coir (Aff.link) is the result of natural waste produced by coconut plantations. The Coco Coir is made from the outer shell of the coconut and it’s also renewable and can hold moisture better than soil by absorbing water more efficiently.

It also comes with naturally present nutrients, neutral pH value and can be used for up to 5 years. If you are growing marijuana indoors, Coco Coir is an awesome choice because it doesn’t develop any fungi even though it retains water for a long period of time.