If you’re looking for an easy, versatile, and cost-effective way to grow hydroponically, ebb and flow hydroponics would be perfect for you.
Whether you’re only beginning to get started with hydroponics or you already have plenty of experience, an ebb and flow system gives you just the right amount of control over your crops, without requiring any micromanagement.
What is exactly Ebb and Flow Hydroponics? Watch this video below:
What is the Ebb and Flow System?
Also known as flood and drain, an ebb and flow setup is quite different to other hydroponic systems.
Instead of the roots of your plants being constantly suspended in a nutrient solution, ebb and flow makes use of two main phases:
- The flooding phase – water and nutrients are flooded over the roots of your plants to feed them.
- The draining phase – in between each flooding, plants are given a set amount of time to drain, so that the roots can then absorb all of the oxygen that they need.
How Does an Ebb and Flow Hydroponic System Work?
In an ebb and flow system, plants are placed into their growing medium and then set into a container that has holes at the bottom.
This container is then placed over the top of a reservoir, which is connected to a timer and a pump.
The timer turns the pump on at regular intervals, and each time this happens, nutrients and water from the reservoir are pumped up into the growing container. This stage usually lasts for a few minutes, giving the roots a good soak.
There is also an overflow tube attached to the growing container – this prevents the water level from getting too high, saving your plants from drowning. As soon as the water level reaches the overflow tube, the excess is sent back down into the reservoir.
Once the timer turns the pump off, all of the remaining water in the growing container slowly drains back down into the reservoir, from the same hole that sent it up.
Pros and Cons of Ebb and Flow Hydroponic Systems
Pros:
- Ebb and flow systems are quite compact, making them adaptable to even small growing spaces.
- Plant growth is rapid when using an ebb and flow system.
- An ebb and flow setup can be adapted to work with plants of all sizes, from seedlings to large, mature plants.
- Since any excess nutrients are sent back into the reservoir, they can be reused, making this an efficient way to grow.
- With the nutrient solution being in a separate container to your plants, it’s easy to control temperature.
- Many plants respond better to an ebb and flow system, since their roots benefit from having some time to dry out.
- Ebb and flow is generally quite a low-maintenance hydroponic system – you only need to replace the nutrient solution every couple of weeks.
- Although they make use of a pump, ebb and flow systems run very quietly.
Cons:
- Since a pump and a timer are key components of an ebb and flow setup, you won’t be able to grow this way without electricity.
- With nutrients constantly being recycled, it can be difficult to keep nutrient levels consistent, and this can affect pH levels too. If pH isn’t constantly corrected, this can lead to a number of problems for your plants.
- Since no water will be flowing past the overflow tube, the tops of growing containers can end up susceptible to algae and other pathogens.
- It takes quite a bit of trial and error to establish optimum timings for water and nutrients to drain in and out. This also varies throughout the growing process depending on growing medium, plant growth rate, and the type of plants you’re growing.
- Plant roots can often end up entwined in the growing tray. This can cause problems if you want to harvest your plants at different times, and it can also increase the rate at which pathogens spread through the roots of your plants.
- Inadequate drainage can leave your plants susceptible to rot and diseases.
This video will give you more information about Ebb and Flow Hydroponics system:
Types of Ebb and Flow Setups
There are a few different types of ebb and flow systems that you can choose from. They all make use of the same principle when it comes to flooding the roots with water and nutrients that then drain away, but there are a couple of differences in how each one is set up.
Single Flooding Tray
This is the easiest ebb and flow setup. Since all plants are in the same container, it’s especially good for temporary situations, as you can easily move plants around.
The main downside is that plant roots can often become tangled together if left in their container for a long period of time.
Multiple Containers
If you want to grow different varieties or sizes of plants in your ebb and flow system, then using multiple containers is the way to go.
Each of these containers will be connected together, so that you still only need one flooding reservoir. The flooding will take place at the same time and at the same rate for all containers.
Surge Tank
While the two setups mentioned above can be adapted to larger plants, space can be a restriction. Since growing containers need to be placed above their reservoir in order for gravity to drain the water out, you can only use vertical space, rather than the space around and below the reservoir.
A surge tank is an extra container that also has a pump. When the nutrients and water from the reservoir are pumped out, they are sent to the surge tank first, instead of to the growing container.
The pump from the surge tank then sends this water out to all of the growing containers connected to it, meaning that these containers don’t need to be placed high up.
Hydroponic Ebb and Flow System Set Up
Before setting up your ebb and flow system, you’ll need to make sure that you first have everything you need.
What You Need for an Ebb and Flow Flooding Tray System:
- Growing container – this needs to have two holes at the bottom; one for the overflow tube and another for a tube that sends water in and out.
- Growing medium – in order to give you full control over the nutrients you’re feeding your plant, you need an inert growing medium, but one that also drains well. A mix of rockwool and sand works well, as do clay grow stones or coco coir.
- Reservoir – choose a reservoir size based on the size of your growing container. Make sure that your reservoir is opaque to prevent the formation of bacteria and algae.
- Pump – you need to go for a submersible pump, such as one designed for a fountain or pond.
- Timer – a basic irrigation timer is all you need.
- Water/nutrient tube – this tube serves two functions; delivering water and nutrients to the growing container during the flow phase, and then draining water away from the container during the ebb phase.
- Overflow tube – this can be a simple tube that carries excess water down from the container into the reservoir.
Choosing a Location
You first need to choose an appropriate location for your ebb and flow system. While some growers choose to build special structures for this purpose, a simple table works well too.
Don’t forget to also consider lighting – no matter how well you set up your hydroponics system, your plants are still going to need light in order to grow.
For many growers, a sunny windowsill provides all of the light they need. However, fluctuating light levels can inhibit growth, especially as the seasons change, which is why others choose to set up grow lights instead.
Setting the Timer
As mentioned earlier, it can take some experimentation before you’ve worked out optimum times for your ebb and flow system.
While you will need to take environmental conditions and plant types/needs into account, the growing medium you choose will have the biggest impact on how you set your timer.
Here are some guidelines for two of the most popular hydroponic growing mediums:
- Rockwool – 3to 5 hours between each flooding usually works well, with a flooding period of around 15 minutes.
- Coco coir – 2 to 4 hours is usually sufficient between each flooding period, but coco coir can vary when it comes to moisture retention. Once the top half inch of your coco coir has dried out, it is time for another flooding.
Putting Your Ebb and Flow System Together
An ebb and flow system DIY setup is relatively easy to put together. Connect your water/nutrient tube and your overflow tube to your growing container, putting one at either end.
Place your plants into their growing medium and then set these into your growing container. Ideally, the plants should be about double the height of the edge of the container.
Hook up your pump and timer and then fill the reservoir with water and nutrients. Once you set your timer, you’re good to go!
Ebb & Flow Hydroponics System Maintenance Tips
Once you’ve got your ebb and flow system up and running, it will need regular maintenance. If you delay this, you run the risk of unwanted pathogens growing inside your reservoir and tubes, which could spell disaster for your plants.
Regularly Replace Nutrient Solution
Ideally, you should be replacing the nutrient solution in your reservoir every two weeks. Some growers may be able to get away with waiting for three weeks, but this depends on nutrient and pH levels.
You may still need to top your reservoir up with water in between this – the smaller your reservoir, the more frequently you’ll need to add in water.
Clean the System
Each time you empty your reservoir to replace its nutrient solution, you should also be giving your system a good clean. Some of the things that you should be doing include:
- Rub down your reservoir and then sterilize it in a water and 15% bleach solution.
- Check that any filters and drainage holes aren’t blocked.
- Blow out all of the tubes in your system to prevent clogs.
Clean the Environment and Any Tools
It’s not enough to just keep your hydroponics setup clean, you need to extend this to the environment around it, as well as any tools you’ve used.
The entire room that your system is in, including your tools, should be kept clean, to reduce any chances of diseases spreading to your plants. This is something that you should be doing daily.
Organic vs Chemical Fertilizers
You may think that organic fertilizers are better, and, in most cases, they are. However, when it comes to a hydroponics system, chemical fertilizers are usually safer.
Since organic fertilizers are derived from natural sources, they contain natural bacterial and fungal strains. These can quickly contaminate a hydroponics system.
On the other hand, chemical fertilizers are usually completely sterile, which will help to keep your hydroponics setup cleaner.
Conclusion
Ebb and flow hydroponics is ideal for those looking for a simple and relatively cheap way to grow plants hydroponically.
Not only will your plants happily thrive, but maintenance is easy, making this one of the least time-consuming ways to grow.
While you may want to branch out into other hydroponic setups in the future, the ebb and flow system is likely to be one that you will keep returning back to, making it worth gaining a good understanding of how to set one up.
