Simple ebb and flow system

Building an Ebb and Flow System
An ebb and flow system is one of the easiest hydroponic systems to build yourself. All of the parts needed can be found locally to you, if you cannot find them we can supply you with ebb and flow trays, NFT channels, hydroponic pumps, fill and drain kits, etc. The Ebb and Flow system is one of the most popular hydroponic methods for its simplicity and ease of use. It basically works like this: A reservoir containing nutrient solution is located below a growing tray. The tray contains the plants that are in containers filled with growing medium such as rockwool, grow rocks, perlite/vermiculite mix, or coconut fiber.The growing bed is flooded periodically by a small pump on a timer to feed and water the plants. The timer then shuts the pump off and the nutrient solution drains freely back into the reservoir drawing oxygen into the root zone. An overflow drain is installed to adjust the nutrient fill height and to ensure the system does not overflow.

Following is a list of parts that are needed to build an ebb and flow system:

Ebb and flow tray
Almost any container may be used that will hold the weight of your plants, growing medium, and nutrient solution. It is preferable to use plastic trays, though trays can also be wood or metal that has been covered with heavy plastic. Trays should not allow light through. Make sure that the tray can drain completely and does not have pools of water, or else you could have problems with root rot (pythium).

Support Structure
A support structure is used when the ebb and flow tray cannot be supported by the reservoir. The ebb and flow tray than sits on top of the support structure which is placed over the reservoir. Support structures can be made from tables, milk crates, sawhorses etc.

Reservoir
Rubbermaid containers, Tucker Totes, plastic trash cans, etc. can all be used as reservoirs. Make sure that the container is clean, blocks light (if you let light into the reservoir you will have a lot of algae growth), and is corrosion resistant. Do not use metal containers without a plastic liner, they will oxidize and could cause nutrient problems.

Pump
Aquarium powerhead pumps can be used, usually at least 500 litres per hour is recommended.

Fill and drain fittings
We sell an ebb and flow drain/ fill kit that can be used most of the time, otherwise you can make your own. Most ebb and flow systems will flow back through the fill fitting, using it as the main drain. Another drain will be set up as a adjustment standpipe/overflow, allowing you to adjust the water level in the tray by adjusting the height of the standpipe. Make sure that the overflow drain will drain as much water as the pump will output. An overflow drain is important to ensure that you do not have a flood in your growing area!

Flexible Tubing
You will need flexible tubing to connect the pump to the ebb and flow tray. Do not use clear tubing or you could have clogging from algae growth..

Plant containers
Plastic nursery pots are the best, but almost any plastic plant pot will do. Make sure that there are hole in the bottom of the pots so that they can fill and drain.
 
Growing Medium
LECA growing medium, rockwool coconut fiber, or a 50/50 perlite/ vermiculite mix. If a perlite/vermiculite mix is used, make sure to use non- metallic screening in the bottoms of the containers to keep perlite form leaking out and clogging the system.

Timer
Any good 24 hour timer with multiple adjustable 1/2 hour or 15 minute duration periods

Putting the system together:

Install the overflow drain and the fill fitting into the ebb and flow tray

Setup the support structure (if needed) and place the reservoir underneath

Place the pump into the reservoir

Put the tray on top of the support structure, positioning overflow drain so that it flows back into the reservoir.

Connect the pump to the fill fitting on the tray with flexible tubing

Connect pump to timer

Make sure that overflow drain drains back into reservoir!

All you need to do now is put the plants into the system and fill the reservoir with nutrients

Running an ebb and flow system
Make sure that the tray will flood as high up on the pots as you need it too. Depending on the size of the pot and the growing media, this is generally 1/3 -1/2 of the way up the side of the pot.

The tray must drain completely and have no puddles left after flood cycles, otherwise problems with pythium could happen.

You must have an overflow drain so that if the main drain becomes plugged the system will not overflow the tray and flood the growing area.

Flood the tray 2-5 times a day, depending on size of the plant. Each flood cycle should run at least 30% more nutrient through the growing media than the media will absorb to provide a leaching effect. This means if the tray will hold 10 gallons of nutrients filled with plants, you want 13 gallons of water to flow through each flood cycle. This prevents salt buildups in the growing medium which could harm your plants. Flood cycles should not run for more than 30 minutes duration, otherwise you could damage the roots.

Change the nutrient solution every two weeks or adjust it according to tds and pH. When topping off nutrient solution in the reservoir, use 1-4 to 1/2 strength nutrient solution. Make sure to check pH levels and TDS levels regularly to maintain optimal growth.

If you should have questions, please post them on our hydroponics forum.