Types of Hydroponic Systems: Intro to Soilless Growing

Hydroponics is a way of growing produce, herbs and ornamental plants without using soil as your growing medium. It originates from Greek etymology, “hydroponics” comes from the words “Hydro” (water) and “Ponos” (labor). The term was coined in 1937 by William Frederick Gericke. William was a researcher at the University of California at Berkeley who pioneered the use of hydroponics for crop production. He became known for growing tomato vines that were over 25 feet tall (7 metres) using water-based solutions mixed with organic nutrients instead of soil. His work was monumental in introducing hydroponics to the public.

There is this horrible misconception that growing hydroponically is very complicated and expensive but once you have a better understanding about it then you will see how simple it actually is. It is also a great way to get your children involved in growing and eating healthy from an early age – It’s a great form of exercise for them, they begin to foster a sense of responsibility towards our planet, it is great family bonding time, it teaches them about nature and gets kids actively involved in good nutrition. Children who grow their own produce, eat their own produce.

There are many advantages to using hydroponics:
  • Hydroponics helps to conserve water.
  • It requires less work.
  • Plants grow faster.
  • You can grow plants where ever and whenever you want.
  • Most systems will use the same batch of nutrient solution for an entire week which means you will save water.

Using hydroponics to grow is becoming more and more popular as people are starting to realize that you get quick, great results from it and can also see how happy and healthy their plants are. There are 6 types of hydroponic options that you can choose from.

The Wick System

This is the simplest of all the hydroponic systems and doesn’t require any pumps or electricity so this is the system you want to be using if you get a fair amount of power cuts/outages. This is a great starter system to get involved in if you are new to hydroponics.

How the wick system works is just as it sounds -  It wicks/sucks up your nutrient solution like a sponge from your reservoir to your plants using the capillary action. You should have a minimum of two wicks for a successful system to transport enough nutrient solution to your plants. Your plant in its container will sit just above your reservoir that has your nutrient solution in it. An alternate method of the wick system is the Aqua Box Spyder. It can be placed in the middle of a raised bed/wooden box and the wicks are spread out under your medium where the plants roots will always have enough nutrient solution readily available.

The only problem with the wick system is that it doesn’t work so well for bigger plants that suck up a lot of water. This system would be better suited to smaller plants that don’t bear fruit such as herbs or leafy greens. Fruiting trees obviously need to suck up a lot more water which goes into producing its fruit and making sure they are healthy and juicy. This system is also less efficient at supplying bigger plants with enough nutrient solution as the plants roots may suck it up quicker than it can be delivered. Unfortunately with the wick system, your plants don’t absorb the nutrients evenly and your wick won’t be able to tell what nutrients your plant needs. Your plant will absorb the nutrients and water that it needs and leave the rest of your solution to sit in your growing medium which can cause a build up of mineral salts over time which will have a toxic effect on your plants. You will need to make sure that you flush your growing medium and your plants root zone with fresh, clean water once a week in order to prevent that from occurring.

The wick that you choose for your system is vitally important as you obviously want one that is going to suck up enough water to supply your plant. A thick candle wick works well but be sure to watch out for algae build up or rotting of the wick as that could also be detrimental to your plant.

The best growing mediums for a wick system would be Coco Coir, Expanded Clay Pebbles, Perlite or Vermiculite. You will need to make sure your reservoir is deep enough so that by the end of the week when it gets close to the time you would need to mix a new batch of nutrient solution that the water level isn't too low that your water pump runs dry. An air stone placed in the bottom of your reservoir that's connected to an air pump with some air tubing will help to aerate your solution to make it last longer as well as supply more oxygen to your plants roots.

The Drip System

Drip systems are widely used due to it being an easy concept to grasp as well as needing very few parts but is also a very versatile system. You pump up nutrient solution from your reservoir through tubing to the top of the growing medium. From there it drips out of the tubing onto the growing media where nutrient solution then drains down soaking both the roots and growing medium all the way to the bottom of the container. From there gravity allows the nutrient solution to flow all the way back to the reservoir. That is called a Recirculating Drip System. You will have to ensure that the plants growing containers will have to be 6-8 inches (15-20cm) above your reservoir to ensure that your solution can properly drain back to the reservoir to be recirculated by your pump. The only problem with any recirculating system is that the pH of your solution will have to be checked on a regular basis to ensure it doesn’t fluctuate as the plants use up the nutrients in your solution.

This system works especially well for larger plants that have a larger root mass. It doesn’t require a lot of water so there is very little to no water that will get wasted as your solution will drip directly to the root zone where it is needed. The more growing medium used in this system the better as your growing medium will retain some water so that means your plants wont dry out immediately if for some reason their watering cycle is interrupted.

Now, there are two types of drip systems – The Recirculating System or Recovery System which we mentioned above and then there is the Non-Recirculating or Non-Recovery System. It does sound like a waste to use a Non-Circulating System but in fact very little water is wasted. If you precisely time your watering cycle with a cycle timer, you should be pumping up just enough nutrient solution to saturate your growing medium and wet your roots so very little actually runs off. It is important to flush this kind of drip system with fresh, plain water to prevent a build-up of nutrients in the growing medium over time.

Another great benefit of the Non-Circulating Drip System is you won’t have to keep checking the pH of your solution in your reservoir as it doesn’t change like in a Recirculating Drip System. An air stone placed in the bottom of your reservoir that's connected to an air pump with some air tubing will be greatly beneficial as it prevents any heavier minerals from settling on the bottom of your reservoir and will help to keep your solution fresh.

The Flood and Drain System

Flood and Drain or Ebb and Flow system is very popular with home growers because of it being a super easy system to build yourself and it is cheap to maintain. Plants also seem to grow very well in flood and drain systems.

With this system, your tray at the top holds the containers your plants are growing in. A timer is set to turn on your submersed water pump which will pump up nutrient solution into tubing from your reservoir below to the tray above where your plants are. It will continue to fill and allow the plants roots to be completely submersed until it reaches a certain level where you have set an overflow tube. At this point your nutrient solution will flow down back into your reservoir. Your overflow tube should be set about 5-10cm below the top of your growing medium to allow the roots to have a proper soaking of nutrient solution but will prevent the top tray where your plants sit from over flowing. Once your pump turns off, the water drains back down into the reservoir through the submersed water pump to be recirculated again.

Another helpful tip to prevent the top tray from overflowing is to ensure that your overflow tube/outlet tube is a wider tube than your water inlet tube. Also, try ensure that your water inlet tube is on the opposite side of the main section of the system to your overflow tube to ensure there is a proper circulation of the nutrient solution.
The only downside to this system is the algae build up in the main section of the system which will have to be cleaned regularly in order to prevent the algae from using up the oxygen in your nutrient solution.

The Water Culture System

One of the simplest hydroponic systems you will encounter which has made it super popular with home growers and commercial growers.

Essentially, your plants are suspended in net pots right above your nutrient solution in your reservoir. They can either float in some Styrofoam or you can cut holes in the lid of your reservoir where your net pots can slot into. The roots of your plant will hang through the net pots and directly into the water/nutrient solution where they remain submerged 24/7. In order to prevent your roots from rotting, an air stone attached to an air pump is placed in the nutrient solution. This will benefit your plants as the roots will be getting oxygen delivered directly to their root zone. It will also help to keep your nutrient solution fresh and assist with keeping it circulated. The more oxygen bubbles rising to the root zone, the better when it comes to this system.

Another way to provide aeration is through falling water. This method is not used often for home growers but on more of a commercial basis. Basically, water falls down into the nutrient solution and the surface agitation causes the solution to circulate and also creates oxygen bubbles that both the plants roots and the nutrient solution will benefit from. The higher the water is falling from and the bigger the volume of water falling is, the more downward force it has when it hits the water’s surface. The more downward force the water has, the deeper the agitation of the solution and therefore the more aeration is provided. This method of aeration is more common in commercial growers because they use large volumes of water compared to home growers.

The Nutrient Film Technique/ NFT System

This system would suit growers who are growing small, quick growing plants for example different types of lettuce, herbs and baby greens.
All NFT systems work in the same basic way – Nutrient solution is pumped up from the reservoir to a manifold which connects a large tube to a series of smaller ones. Each one of the small tubes will run your nutrient solution to one side of each of your sloped growing channels with the plants in it. A very thin layer of the nutrient solution flows through each channel where your plants are to the other side. As it flows, it passes by each plant and wets their roots that are hanging down onto the bottom of the channel. Your plants are suspended in your channel by placing seedlings (which have been germinated in cubes of Rockwool or Peat Pellets) into Net Pots. The Net Pots slot into the holes you have created on the top of your channel. The roots of each seedling hangs down to the bottom of the channel where they absorb their nutrients from your flowing solution. Any excess nutrient solution that has not been sucked up by the plants roots will flow to the other end of the channel and is then guided back to the reservoir where it will be recirculated through the channels again.

This way your plants roots are getting more than enough water/moisture from the nutrient solution that flows passed them and the roots also get plenty of oxygen from the air surrounding them in the channel to keep them fresh and healthy.

It is important to get the correct slant of your channels so that the water doesn’t flow too quickly passed the plants roots but it also doesn’t flow too slowly and end up pooling up around your roots as this will cause root rot. A good rule of thumb is for every 30-40 inches (76-101cm) length of your channels, 1 inch (2.54cm) slope is recommended. Also, it would be advisable to make your channels slope adjustable while they are still seedlings. As your plants roots grow in size so do their roots and the nutrient solution won’t flow passed your plants roots as well as they did when they were younger which could cause the solution to dam up in areas and cause root rot. Therefore as your plants roots grow in size, the more you should slop your channels to ensure the solution still flows nicely.

Tip: Try keep your channels to a maximum of 30-40 feet (10-15 metres) long, anything longer and your plants might struggle with nutrient deficiencies.

The rate that the solution flows passed each plant is important too. Each channel should be getting ¼ gallon to ½ gallon (1-2 litres) per minute or between 15-30 gallons (60-120 litres) per hour. While your plants are still seedlings, you can cut the recommended flow rate in half and increase it as they grow in size.

The Aeroponic System

Aeroponics – A simple concept to grasp but the most technical and one of the most expensive of all the hydroponic systems. The plus is that this system will use little to no growing medium so you will save some cash on that front. This system allows the roots of your plants to get maximum oxygen and because of that fact, they grow quicker than with other hydroponic systems. Aeroponic systems also use less water as they use misters to deliver the nutrient solution to the root zone. If you are growing root crops in this system, they are easier to harvest when the time comes.

The downsides though are that it is more expensive, the mister’s heads need regular cleaning as nutrient solution can build up in them over time and you will have to have replacement mister heads on hand to use while you are cleaning them. Also because the plants roots are hanging in midair, they are far more susceptible to drying out if for some reason the misters spraying cycle is interrupted so this system is not advisable if you have a lot of power outages as even the smallest interruption could cause your plants to perish. You also won’t have as much margin for error with your nutrient levels in your solution as anything too strong or too weak could be detrimental to your plants.

For this system your plants will be suspended in Net Pots or Rockwool Starter Plugs and placed into holes perfectly cut to fit the Net Pot or Rockwool Plug. The roots of the plant hang down inside the growing chamber where they are sprayed with a mist of nutrient solution at regular short cycles. The regular watering cycles ensure that the roots are always moistened as well as provides the plant with just enough nutrient solution. It is advisable that the growing chamber where the roots are hanging be completely light tight and almost air tight to keep the humidity in. You still want to allow fresh air to enter the chamber but you also need to prevent any water from spilling out and obviously, it will need to be pest proof.

Roots that are sprayed with a fine mist of nutrient solution grow much better and faster than roots sprayed with sprinkler head type droplets. The perfect aeroponics system should have a good balance of moisture, fresh oxygen and nutrients.

Now that you are informed on the different types of hydroponic systems there are to grow in, visit us in store or give us a call so we can help make all your hydroponic dreams comes true.

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Information sourced from www.homehydrosystems.com

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Diederick Kleyn - August 1, 2019

Can clivias grow in a hydroponic system?

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