With so many different hydroponic systems around it's hard to know which one is best for you. One of the most popular methods, which has withstood the test of time better than many others in the past, and mimics the tides of the earth, is EBB and flood. Here is a guide to EBB and flood for anybody just starting out, or interested in trying this technique of hydroponic gardening.
What is EBB and Flood?
In an EBB and flood system, the roots of plants are not always submerged in the water. This means that the water levels are always on a cycle of flooding, and draining. This is just like the natural flood and drain of the oceans tides. As the water flows in it floods the area. After some time, the water then drains back out to the sea. This process repeats endlessly, providing bouts of fresh water and nutrition, followed by bouts of oxygen and airflow.
The traditional way of achieving this is to have a tray in which the plants sit that fills of with water from a separate holding tank. Once filled it covers the plants roots and allows them to feed. The water then drains back into the holding tank to allow the roots access to oxygen and to await the next cycle. This is the oldest method of EBB and flood and is still perfectly valid today. These are the cheapest and simplest EBB and flood systems yet are highly effective and easy to maintain.
New designs involve many individual pots connected together with a separate holding tank. This allows additional pots to be added with ease, and minimizes the loss of water.
The Benefits of EBB and flood
First of all, let's investigate the benefits that can be had from an EBB and flood style system:
EBB and flood offers the benefits of modularity as a growing system. This means that it can be used for a wide range of plant sizes, types, and can easily be extended by adding more flood tables or buckets. It also allows the plants to be moved around easily to accommodate additional plants or to move smaller plants closer to the light source.
This is a perfect system for anybody who wants to experiment with hydroponics or who is growing different types of plants in the same system and needs the ability to move their plants around to make sure the light is able to hit them all evenly.
2. Cheap to make
There are in fact some very nice, yet more expensive EBB and flood systems out there, but for the most part this system can be made at home using simple materials. The basic principles of this system (which we will get into more detail about below) consist of 2 containers. The first one stores the water, while the second holds the plant. Water is pumped from the water storage to cover the roots. Once the roots have been soaked, the water drains back into the storage tank. This can be expanded to virtually any size imaginable.
This type of system can be made from anything, and there have been some incredibly ingenious DIY projects circulating the internet using this basic concept.
3. Easily expandable
One of the main selling points for a system such as this, is the ability to expand it whenever you want. If using a flood table, this just means adding another flood table and another pump. The same storage or reservoir tank can even be used in most cases, the only thing to keep in mind is that the cycles are not at the same time allow one table to flood and drain before having the other table fill up with this same water. Some careful tweaking of your timers can easily achieve this.
The basic setup of an EBB and Flood System:
1. Reservoir tank
A reservoir tank to store the water while it is drained. If you think about the tides, this is the place water goes during “low tide”.
2. Grow beds or buckets.
This is where the plants are kept, and where the water fills during “high tide”.
3. A water pump
A water pump is used to move the water from the reservoir to the grow beds or buckets. In most cases the drain from the grow beds uses gravity to return the water to the reservoir at the end of the cycle, however some systems have this reversed and use the pump during the drain (low tide) cycle instead. Either system works.
4. Pump timer
A pump timer is a necessary piece of equipment when running an EBB and flood system because it is what controls the tides of the system. There is another option which involves running the pump constantly with the incorporation of an auto siphon.
A nutrient formula is added and mixed into the water contained in the reservoir prior to running the system. This should be pH buffered, and replaced every week.
6. Overflow valve
This is a valve contained at the highest level you want the water level to reach, which allows anything in excess of this line to drain back into the reservoir. This is used to prevent overflows of the system which are otherwise common when trying to get the balance right for your system
What Timing Should I use With My EBB and Flow?
Everybody you ask will give you a slightly different answers for this, and it's hard to say that there are any right and wrong answers for this. For beginners, a good rule of thumb is to allow 5-10 minutes for the system to fill, with the drain taking about the same. This can run once or twice per day if using rockwool as it holds a lot more water. For other mediums, or if you notice your rockwool drying out too fast in between flood cycles, this can be increased to 5 or 6 flood cycles per day.