Hydroponics System – EBB, DWC, NFT?

Starting your indoor farming using hydroponics and considering which hydroponics system is best suitable for your case? In this article, I'll be discussing the most common hydroponics system in use today and hopefully, you can use the information to decide the best system for yourself.

The 7 Systems

Let's start the list from beginners to expert level.  I'll share my experience on each of these system and any recommendations using them. We can break these systems down to 3 main topics;

1) Is it a circulating or non-circulation system.

2) Is it possible to build it yourself or better to get it off-the-shelf from manufacturer.

3) How much time needed to maintain the system weekly. 

KRATKY SYSTEM - The idol proof

It is the only system in this list that allow you to grow without any moving parts that need electricity. It can be a 100% "hands off" system if you choose the right crops to grow. This system was first research and recommended by Dr. Bernard A. kratky from University of Hawaii at Manoa, hence named Kratky System. Dr. Kratky published a whitepaper on this topic in 2010 and has made it available publicly. 

In this system, we fill the bucket/reservoir with nutrient water to the top touching the net pot holding the seeding. Ideally, you will want to use seedlings that are at least 1 - 3 weeks old. Always check the EC and pH before you leave the system to do its wonder. Adjust accordingly if needed. 

As the plant grows, it will use up the water and thus the water level will drop as time passes. At the same time, roots will be growing reaching downwards with the falling water level. Eventually, there will be an air zone between the net pot and water level. This is critical because this is where the roots will be receiving their oxygen which is a vital ingredient for plants to survive if not thrive. 

Due to its simplicity setup, Kratky system will be an ideal beginner setup especially if you have never tried hydroponics prior. However, as you will realized, there are quite a few challenges with this system. 

PROS;

  1. Extremely easy to setup 
  2. Need no prior experience 
  3. Zero moving parts thus no mechanical failure possible 
  4. Suitable for small space 
  5. Effective rooting method 
  6. High Mobility 

Cons 

  1. Need to be selective on the type of crops  
  2. Need to prepare the right amount of nutrients water 
  3. Unwanted pest could get into the bucket. e.g. mosquito, insects, frog, etc 

My recommendation; 

Use Kratky for small leafy crops like herbs. You do not want to use this for fruiting crops and crops that will grow big. A simple DIY kratky can be done using a mason jar with nutrients water. Basil or mint plant work best in them by your kitchen windowsill. 

Example of commercial product

DEEp water Culture (DWC) - Most Popular

One of the most widely used system due to its simple and easy to build design. The traditional design typically comprised of a main reservoir that hold the nutrient solution. Plant are suspended by cutting small hole on the bucket's lid to hold the net pot. Plant roots are able to hang freely and submerged in the highly oxygenated nutrient solution. Air pumps and air stone are key components PROVIDING oxygen to the nutrient solution and is crucial to the plant health.  

More advanced commercial product improved from this stand-alone systems to a modular systemsIn this modular design, several buckets are connected to a central reservoir creating an active system where the nutrient solution is able to cycle from the reservoir to all the connected plant pots and back to the reservoir (closed loop) 

Pros

  1. Very low maintenance needed. Occasional top up and checking of nutrients water parameters still needed. 
  2. Great for water loving, rapid growing plants. 
  3. Allows for large root mass. 
  4. Cost effective to diy. 
  5. Only one moving parts (air pump) thus min failure. 

Cons

  1. Reservior temp can fluctuate thus chiller might be needed. 
  2. Plants can be prone to root diseases with DWC system. 
  3. May foam up  
  4. pH fluctuation/ monitoring required. 
  5. Root mass may grow so large, it will clog the irrigation lines or when the roots outgrow the bucket. 

MY RECOMMENDATION; 

Should be you starting point if you are planning to go the DIY route. Just need to take care of the reserviour size accordingly with the plant to grow. Choose those plants that love water and can withstand always submerge in water like lettuce, bok choybasil, okra, kale, chard. 

EXAMPLE OF COMMERCIAL PRODUCT

wick system - Self Watering

The wick system is also another system that does not have any moving parts and simple to setup for beginners. The wick systems have been widely adopted by teachers in classroom and for conduct experiment to explain how plant grows and the important of water (hydroponics). 

How wick systems works is as the name implies, a wick is used in the net pot covered by the grow media and extend all the way to the reservoir where nutrients water are. It uses the capillary effect to move the water from the reservoir to the plant roots. You can use more wicks to keep the grow media moist. Typical wick material are rope, string or strip of felt. 

Pros; 

  1. Does not need electricity
  2. No moving parts  

Cons;

  1. Does not do well for bigger plants or plants that need a lot of water.
  2. A high possibility of toxic build up in the wick as time passes as mineral salts are left behind.
  3. Water level need to be maintain high to minimize water travelling long distance up the wick. 

MY RECOMMENDATION; 

Use wick system for small setup. It work best for herbs and small ornamental plants. There are many commercially ready products that uses this method. Many are built for decorative items, educational purpose and all are made to be easy to use cos of the self-watering capability.

EXAMPLE OF COMMERCIAL PRODUCT

Chuppon Cultivation Kit - Wick

Chuppon Cultivation Kit

DRIP system - Old meet New

An adaption from traditional soil gardening. Drip system for hydroponic can be setup  by home gardener or commercial farms. Many Commercial farm uses it because it is a system that can be easily modified and controlled centrally.

It works by dripping drops of nutrient water onto the top of the net pot holding the plant. The reservoir hold the nutrient water and can be shared by other systems also.  Drip system can be setup to be a circulating or non-circulating system. In a circulating system, the net pot will be place on top of the reservoir to allow any run off water to flow back into the reservoir.

Pros;

  1. Can use any type of media. 
  2. Cost to build is low. 
  3. You can have continued drip or a timed system. 
  4. Do not need a huge reservoir.  
  5. Flexible. Can be set as a recirculating reservoir (closed loop) or run off system. 
  6. Suitable for long term setup. 

Cons;

  1. The drip line can clog easily or harden and break over time.
  2. Not a beginner DIY as more time consuming to set-up. 
  3. High investment cost. Pump, drip emitter, drip line, etc. 
  4. More grow media are needed
  5. Need electricity to run the water pump. 

MY RECOMMENDATION; 

Do not attempt to DIY this unless you have decent DIY experience. Drip system generally need alot more space. However, with good planning, you can still can have a drip system with minimum footprint. This system works great with fruiting crops like tomato, cucumber, pepper, etc. 

EXAMPLE OF COMMERCIAL PRODUCT

Ebb and Flow system (EBB) - Float and Drain

The Float and Drain system works by flooding the grow area with nutrient water for a period of time and drain them back into the reservoir. This can be done using a water pump with a timer.  

Most commonly setup as a recirculating system. The return nutrient water will be drain back into the reservoir for close monitoring and control to ensure the nutrient water are always in the desired parameter. This is also the system where most automation happens in hydroponics. You can add pH, temperature, ECC controller to the reservoir and program dosing kit to add nutrient accordingly. Temperature will be controlled using heater and chiller.

 Pros;

  1. You can re circle your nutrient solution. 
  2. Requires few parts to make up the system.
  3. Generally easy to build. 
  4. Maintenance can be automated. 
  5. Able to support any type of grow media may be used. 

Cons;

  1. Height issue can be a problem due to the height of the reservoir and tray. 
  2. Salts and minerals can easily build up in the growing media due to bottom flooding in lieu of top flushing. 
  3. Mineral build up can cause a nutrient lockout, which can also cause a nutrient deficiency.

MY RECOMMENDATION; 

Take extra care when working with small plants with short roots in the grow media. The roots may not reach the float line and end drying up. Thus you may need to add drip lines until the roots grow longer. This add certain layer of complexity as you will be using both Drip and Ebb in one system.

EXAMPLE OF COMMERCIAL PRODUCT

Viagrow Complete Ebb & Flow Hydroponics System (O.D. 53” length X 53” wide x 25” high)

Viagrow Complete Ebb & Flow Hydroponics System (O.D. 53” length X 53” wide x 25” high)

NUTRIENT FILM TECHNIQUE (NFT) - commercial farmers Fav

Nutrient Film Technique (NFT) system is probably the defacto standard for hydroponics especially in many commercial farm. The system involve have the nutrient water been pump into the grow tray or tubes where the plant are grown. This allow the roots on they tray or tube to be in constant contact with the nutrient water thus encourage healthy growth.  

There are 2 variants for NFT. The common practise is to have a thin film (0.5mm to 1mm) of nutrient water constantly flowing through the grow tray or tube. This allow the root above the film to develop "breathing" roots to take in oxygen. In some cases, a much deeper (2-3cm) film are desired due to the crops or plant selection. 

Pros; 

  1. Relatively cost effective  
    1. No stagnant water 
    2. Recycling system thus save water. 
    3. No parts prone to clogging. 
    4. Does not need a timer. 
    5. Grow media is not optional. 

 CONS; 

  1. pH fluctuation is possible thus regular testing needed. 
  2. Water pump is critical and if break can be disster as plant die quickly due to dry roots. 
  3. May need a chiller if water warm up 
  4. Only work for plants with roots that can reach the bottom of PVC. Thus a grow out area needed 

MY RECOMMENDATION; 

A good long term system to invest in for urban farmer if space allows. You can grow most crops/plants using this system with regular maintenance.  

EXAMPLE OF COMMERCIAL PRODUCT

NFT Gro-Tank & Multi-Duct Systems

NFT Gro-Tank & Multi-Duct Systems

Other similar hydroponics systems worth mentioning

Aeroponics - Air + Water

Aeroponics system allow growing plants by suspending their root in air and regularly spraying them with a nutrient water. It is an efficient system where many who uses it reports that better yield from their fruits and vegetables.


EXAMPLE OF COMMERCIAL PRODUCT

AeroGarden Bounty with Gourmet Herb Seed Pod Kit

AeroGarden Bounty with Gourmet Herb Seed Pod Kit

Aquaponics - Fish + Water

Strictly speaking, Aquaponic is also a system based on hydroponic principle. It is a system that uses the waste product from the fishes as a nourishing component for the plants . This make it a system that is sensitive to small changes due to the closely knitted ecosystem. We may revisit this topic at a later time as I am a vivid hobbyist of the home aquarium.


EXAMPLE OF COMMERCIAL PRODUCT

AquaSprouts Garden

AquaSprouts Garden

Trackbacks

  1. Commercial Hydroponics Strawberry Farm in Singapore - pluckgreens says:

    […] If you are wondering, yes, they are using the Ebb n Flow (EBB) system. To find out more on the EBB system, read this post. […]

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