A Guide to the Different Types of Hydroponic Systems

 

There are 6 types of hydroponic systems, and each system has its own advantages and disadvantages. There are also numerous variations on these systems. 

 

The 6 most common types of hydroponic systems are: 

1. Wick systems
2. Deep Water Culture (DWC) systems
3. Ebb and Flow systems
4. Drip systems
5. Nutrient Film Technology/Technique Systems (NFT) systems
6. Aeroponic systems
   

 

These 6 systems will be looked at in more detail below 

 

Wick Systems

Wick systems are typically considered to be one of the easiest types of hydroponic systems, and most people can grow plants using this system quite easily. It is a great way to start to learn about hydroponics. This system does not need an aerator, pump, or electricity. Plants are placed in a growing medium, such as perlite or vermiculite, and nylon wicks that go into the nutrient solution are put around the plants. The nutrient solution travels up the wicks and soaks the growing medium around the roots of the plants. Wicks are typically made from cotton rope, nylon, string, or felt. This type of hydroponics is known as ‘passive’ because there are no mechanical parts, such as a water pump, needed to make it work. If you want to start a hydroponic garden in a place where electricity is not available or is unreliable, this can be a good technique. 

 

The technique that makes the wick work is called ‘capillary action’. The wick absorbs the nutrient solution, then transfers this once it contacts the growing medium. The growing medium does need to be porous to allow the water transfer to take place. Growing mediums such as coco coir, perlite, and vermiculite can be good mediums to use because they work well with the wick without becoming too wet themselves. When plants need some nutrients, they’ll simply absorb some from the wick. One of the benefits of this system, as well as it being inexpensive and not needing much maintenance, is that the amount of nutrients your plants get is self-regulated. If they need a lot of nutrients and water, then it will give them more.

 

While this type of hydroponic system is fairly simple, it can’t get vast amounts of nutrients to plants, so it’s most suited to small plants and herbs. You wouldn’t want to try to grow peppers or tomatoes using this method because they need a lot of nutrients to grow and take in more nutrients than wicks could give them. Wick systems also don’t give every nutrient your plants need evenly, and mineral salts can build up, so if you decide to use this technique it’s a good idea to flush nutrients with fresh water every two weeks. While you don’t need aeration to use the Wick system, some people choose to include an air stone and pump to add extra oxygen.

 

 

These systems are easy to set up and maintain, and once you’ve set it up, you don’t need to do much. If you’re a beginner or you have children interested in hydroponics, then this can be a good system to start with. There is very little cost involved, the setup process is not complicated, and you don’t need any experience at all for this to work well; wick systems can even be used in small spaces. It’s a nice way for anyone interested in hydroponics to start out. 

 

Wick systems are great for growing lettuce and herbs, such as basil, comfrey, chicory, oregano, thyme, rosemary, and mint. They wouldn’t be suitable for tomato plants because these need a lot of nutrients and a lot of water. Root vegetables would not do well in such a moist environment. Wick systems are susceptible to being humid and damp, and this can cause fungus and rot. If the wicks aren’t placed close enough to the plants’ roots or if they aren’t maintained properly, then the plants can die. 

 

A good tip for the Wick system, which makes it just that bit more efficient, is to put the grow tank above the reservoir, and place a hole in the bottom of it so that any excess nutrient solution wouldn’t remain in the grow tank where it could cause stagnation and disease, but instead it would be recycled back into the reservoir below.

 

Deep Water Culture (DWC) including the Kratky Method

 

The Kratky Method will be covered first, as it’s a simpler version of the Deep Water Culture system.

 

The Kratky Method

Kratky systems are very easy to establish and maintain. Besides Wick systems, Kratky systems are one of the simplest forms of hydroponics. It’s a good method for growing individual plants, but not suitable if you want a hydroponic garden that includes a wide range of plants. You don’t need pumps for this method to work. This can be a nice method if you want to give hydroponic gardening a go and just want to start with one or two plants. It would allow you to make a judgement call after this as to whether you would like to expand your hydroponic garden to something more diverse using a different method and whether you have the time available to do so. 

 

For the Kratky method, you need a container. You can use a mason jar if there is nothing else to hand. You will also need a net pot and nutrient solution. Fill up the container with the nutrient solution until it covers the bottom third of your net pot. There will be an air pocket between where the bottom third of the net pot is submerged in the nutrient solution and the plant that grows above the water level. This will allow the plant to get essential oxygen. 

 

 

Sometimes plants can get root rot in this system if there isn’t much of a gap between the roots and the plant above the surface. If this system doesn’t seem quite right for you, then you can consider a Deep Water Culture (DWC) system instead. 

 

Some of the advantages of the Kratky Method are that it’s very simple, it’s inexpensive, and there are very few parts to it. It’s not complex, and it’s very simple to maintain. While the simplicity of the system is appealing in that it doesn’t take much to set up, doesn’t cost a lot, and it’s not difficult to maintain because there are no mechanical parts, such as a water pump, this can limit the control you have over feeding your plants. It can sometimes be difficult to top up the nutrients accordingly, and no oxygen is getting to the roots. This is a good method to try out hydroponics, and it’s great for children to have a go. If you simply wish to grow a decorative plant—it’s fine, but this isn’t a technique to provide you with regular food to help you live a sustainable lifestyle.

 

Deep Water Culture (DWC) Systems

A DWC system puts the roots of your plants into the nutrient solution. You will need to put oxygen into the water too in order for plants to survive, so will need to use something like a diffuser or an air stone for a DWC system to ensure that the solution is aerated. Any plants you place in the solution should use net pots to keep them in place. Usually, these plants are placed in a foam board or in the top of the container that you’re using as a reservoir. Plants will easily be able to absorb the nutrients because their roots are directly in the solution, and this means they should grow quickly. The key thing to look out for and be aware of is root rot. You’ll need to ensure that your roots are kept clean and healthy. 

 

DWC hydroponics is low maintenance once the initial set up has been done. You will need to replace the nutrient solution every 2–3 weeks and ensure the pump works properly at all times in order to provide oxygen to the air stone. It is possible to make DWC systems inexpensively at home, and you can pick up a pump and an air stone cheaply from a pet store or a garden center. This type of hydroponic system is good for growing herbs, lettuce, and leafy greens but would struggle with larger slow-growing plants or anything that flowers. You can grow tomatoes and peppers in a DWC system with a bit of work.

 

You can use an old aquarium and Styrofoam for this and use that as a “lettuce raft”. This type of system doesn’t take a lot of space, and generally it will yield more successful results than the Kratky method.

 

 

DWC is a method used in the past, and it’s one step up from the Kratky method where you have solution in a tank with an air pump that helps give the plants oxygen. But hydroponic gardeners don’t tend to use this method often because typically they prefer two tanks and two pumps. It’s better than the Kratky Method because it uses an air pump, which helps provide more oxygen to the plants’ roots, but it’s still simple and doesn’t have a lot of mechanical parts. 

 

In a DWC system, the water does stay still a lot, and this can cause bacteria, algae, fungi, and mold to grow, which is bad news. While an air pump can give some aeration, depending on how many plants you have in your tank, whichever plants are nearest to the air stone will take most of the oxygen. The best place to place an air stone is in the middle of the tank to try to be fair, but the plants on the edge won’t get their fair share of oxygen. 

 

Deep Water Culture systems don’t work with vertical gardens or hydroponic towers, so they’re not really designed to fit in a small space or to make the best use of the space you have available. If space is an issue for you, then some of the other hydroponic systems may work better, for example, an Aeroponic system. DWC systems are more difficult to clean because you would need to remove all the plants to empty the tank and get rid of any algae, so you would typically do this when you’re not using the tank at all or when you’re changing over crops.

 

Ebb and Flow Systems

Ebb and Flow systems are also sometimes called ‘Flood and Drain’. In this system, your plants are flooded with the nutrient solution on a cycle. Many home gardeners use this technique. Plants are put into a grow bed filled with either perlite or rockwool. That grow bed is flooded with a nutrient-rich solution until the water is a couple of inches below the top layer of the perlite or rockwool to ensure it doesn’t overflow. This technique uses a water pump to flood the grow bed, and it will switch off on a timer so that water can drain and go back into the reservoir. 

 

This technique can be used to grow most plants and is particularly good for vegetables such as carrots and radishes. It is good for root vegetables because unlike in the DWC system mentioned above, plants are not constantly exposed to water in the Ebb and Flow system. When the water ebbs, the grow bed empties, and the roots will dry out and take in oxygen before they are flooded again. An air pump should also oxygenate the water in the reservoir as it sits there before the next flood cycle.

 

It is advisable not to grow especially large plants with this technique because they need a lot of space to grow, and you also need to fit the growing medium, such as perlite or rockwool, and the plants’ roots into the grow bed. If you want to grow root vegetables, you’ll need a deeper bed. You can grow things like tomatoes, cucumbers, peppers, peas, beans, beets, strawberries, and carrots using an Ebb and Flow system. You can use grow rocks and clay pebbles as a growing medium because you can easily clean and reuse them, and they’re lightweight too.

 

You need to ensure the pump is working so that the solution ebbs and flows properly, and that the grow bed is draining adequately to prevent root rot. You also need to make sure it’s all clean to prevent mold and insects. One other thing to consider is the growing medium that you grow the plants in. It will be flooded, so it’s best not to use perlite because it’s too light and plants may float or tip over. Slightly heavier growing mediums, such as rockwool or coco coir, are better to use with Ebb and Flow systems.

 

This system does need to be balanced and timed correctly because if it isn’t, there is a risk that you could either oversaturate your plants or they could dry out. You will also need to monitor the pH level of your nutrient solution regularly.

 

With Ebb and Flow systems, you usually irrigate in cycles where you have a time for irrigation and a time where the plants are dry. The irrigation typically occurs for 10–15 minutes every two hours of daylight. This includes the time that you have grow lights on too. A minimum time for irrigation would be 5 minutes, but you would typically need more with most hydroponic gardens. The plants won’t require nutrition and water to photosynthesize when it’s dark, so they don’t need irrigating then, and your plants can rest during that time. The only time you would irrigate at night is if the weather is especially hot and dry.

 

The Ebb and Flow system isn’t a system that newcomers to hydroponics would immediately jump into because it does have some complexity to it in terms of setting up the irrigation with plastic pipes and using a reversible pump and timer. You will also need to get used to the cycles and phases that this system requires. It has a number of parts to the system, and if something breaks, especially the pump, this can prevent the system from working properly. It’s really important that the roots don’t dry out completely. You will also need to know about the crops that you are growing and what their nutritional, water, and humidity requirements are. You will need to clean the pump frequently because bits of roots or leaves from plants can get stuck in there. The piping may also become clogged from time to time. Keep in mind that the pump will generate some noise, so it’s important to consider where you would place your system. After all, you don’t want it to annoy you or disturb your sleep.

 

Nutrient Film Technology/Technique (NFT) Systems 

NFT systems have a relatively simple design but can be scaled up if required. In an NFT hydroponic system, the nutrient solution is first put into a reservoir, and then the solution is pumped from it into sloped channels. A thin layer (a ‘film’) of nutrient solution constantly flows through the channels, which gives the roots the nutrients and water they need, while allowing the upper part of the roots to breathe. If there are excess nutrients, these flow back into the reservoir.

 

Typically, a growing medium would not be used in an NFT hydroponic system so that it doesn’t stop the flow of nutrients. You will need net pots to support the plants’ roots, though. The channels that this system uses are small, so it’s best to grow plants with small roots in this system. You can easily scale this system up to grow large numbers of smaller plants, and in fact, many commercial growers use this type of system.

 

The water in the reservoir needs to be aerated with an air stone. A pump that is responsible for pumping the nutrient solution back to the channels will be submerged, and this recirculates and recycles the solution. Roots in this technique can spread horizontally and end up having a mop-like appearance. The tanks need to be angled so that they’re not perfectly horizontal. The nutrient solution enters the grow tank on the side, and then flows down a gentle slope until it’s collected and recycled. 

 

The angling needs to be done carefully at just a few degrees. You don’t want the nutrient solution rushing by too fast, but the pipes shouldn’t be too straight either because the solution would just sit there and stagnate. You can always buy kits if you’re worried about what inclination you should have the grow tank set at. 

 

If you decide to make your own NFT hydroponic system, the inclination should be 1:100. This means the inclination for the slope should go down an inch or centimeter for every 100 inches or centimeters. The angle would be 0.573

 

Plants that tend to do well with an NFT hydroponic system include plants that are light, such as leafy greens, including mustard greens. lettuce, kale, spinach, and strawberries do well too. If you want to grow tomatoes and cucumbers, which are heavier, then you would need to use trellises to help support their weight.

 

There are a few different ways NFT systems can be implemented, and these can include a stacked NFT system, which is a great space saving way of doing this. You can use a slanted wall NFT system, which is good if you intend to place the system against a wall. You can purchase kits. You can also buy small versions of commercial systems. Or you can build your own system.

 

If you decide to expand your NFT hydroponic system and set up more crops and more channels, it is sensible to use different reservoirs. This way, if you experience a pump failure or any diseases, this will only impact one reservoir and the channels associated, and not your entire garden. If your pump fails, then your plants can dry out and die quickly because there is nothing around them to keep them moist and supplied with nutrients, so you do need to keep a good eye on this. If you ever go on holiday and leave anyone else looking after your hydroponic systems, they do need to be warned to regularly check that everything is working properly.

 

Something else to keep in mind with NFT systems is that the plants do need plenty of space because if they’re too close together and the roots are compacted, the channel can become clogged with roots, and they can overgrow and become intertwined. As a result, the water containing the nutrient solution would not be able to flow over this, and the plants would starve and die. If some plants at a part of a channel don’t seem to be doing as well as others, you could remove some plants.

 

The main benefit of NFT systems is that they don’t need a lot of water because they recirculate it. Because the water is constantly flowing, less salts gather at the plant roots, compared to some other forms of hydroponics. NFT systems typically don’t use a growing medium, so you don’t need to buy or replace this as an ongoing cost. NFT systems allow you to constantly adjust inputs, and this can really help growth. However, they can also have a greater cost and take a bit more time and expertise to set up and maintain.

 

Drip Systems

Drip systems, also known as ‘top feed’, are easy to alter and make changes to. The nutrient solution is taken from the reservoir and placed into a tube that sends the solution directly to the plants’ roots. There is an emitter at the end of the tube to control how much solution a plant gets, and this can be adjusted to meet the requirements of each plant. These systems can be big or small, depending on what you need. This is the type of system that is often used for commercial settings because they can be made to a large scale. These systems tend to fall into two categories: recirculating and non-recirculating. A recirculating system is one that drips constantly. If there are any extra nutrients, these go back into the tank holding the solution. You do need to be careful to monitor the nutrient and pH levels when the solution is recirculated. In a non-recirculating system, any excess water drains out and goes off as wastewater.

 

Drip systems tend to use two pumps, a reservoir, and hoses to deliver the nutrient solution to the roots of your plants. One pump keeps the nutrient solution moving and supplied with oxygen, while the other pump moves the solution through hoses to drip emitters that then drip nutrients onto the growing mediums.

 

Drip systems are very popular, and a lot of commercial growers use these systems. It is probably my favorite type of hydroponic system. The system many home growers use is called a ‘recovery’ system (this is another name for the recirculating system mentioned above), where excess water goes back into the reservoir and is recirculated. Commercial growers tend to use non-recovery (or non-recirculating) systems, where any excess water drains out and goes off as wastewater. While this may sound like it’s wasting water, commercial growers do use their water sparingly and use elaborate timers to reduce any waste.

 

The type of growing medium you use may have an impact on whether you continuously irrigate or whether you irrigate every few hours. Continuous irrigation would be used with hydroponic expanded clay, whereas with rockwool, you would tend to irrigate every 3 to 5 hours. You may need to do some testing with your irrigation cycles initially to work out what works for your hydroponic garden, as every garden is different.

 

If you decide to go with a Drip system, one thing to keep an eye on is how much the nutrient solution has fluctuations to its pH levels. Plants will obviously take nutrients out of the solution, so you will need to monitor the solution and adjust it accordingly. You need to check that the growing mediums aren’t overrun with nutrients, and if they are, then they can be washed and replaced.

 

 

One of the great things about Drip systems is that you can grow large plants in them, such as melons, zucchinis, pumpkins, and onions. You can grow fruit trees too. These systems can hold a lot of growing medium and tend to work best with peat moss, rockwool, and coco coir. If you wish to scale up, this can be easily done with extra reservoirs and different timing schedules according to the needs of the plants. You can have vertical gardens and towers with Drip systems, which means you can fit a lot of plants into a compact space. You can make use of unusual spaces too, using pots and hoses to get this system to work.

 

A Drip system can have a flexible approach that fits most spaces, and you can grow either singular or multiple plants. If you decide you want to recycle the water, this can lead to higher maintenance. You can really control when plants are fed and watered with this type of hydroponic system. It is also less likely to break compared to some of the others, and it’s relatively cheap to set up. It could be considered overkill for a small garden, so maybe this isn’t the first hydroponic method to try. But if you have tried others with good success and hydroponic gardening really appeals to you, this could be the next step that you work towards.

 

Drip systems do require some maintenance. You will need to be constantly monitoring the pH and nutrient levels. You need to ensure that not too many nutrients have built up. You will also need to wash and flush out delivery lines because they can become clogged with bits of plants.

 

The main downside to Drip systems you should be aware of is leakages with the pipes and hoses. A top tip to quickly find these is to use some colored tissue paper that goes darker when wet so that you can see exactly where on the pipe or hose the leaks are coming from. This isn’t a big deal, as pipes and hoses are cheap and relatively easy to replace. It is worth having spare pipes and hoses to hand so that you can fix a leak even if it’s late at night or at a time when shops are closed. Another issue with this system is that the water pump can break, so your plants will be left without nutrient solution. It is always worth getting into a routine where you spend a few minutes checking that the water pump works properly each day.

 

As mentioned earlier, the Drip system is my favorite type of hydroponic system. I think it’s incredibly versatile. It’s relatively easy to set up, inexpensive, and simple to maintain. Plants are aerated in this system, and you can fully control the irrigation.

 

Aeroponic Systems

These systems can be a bit trickier to put together. They are quite high tech and therefore tend to be more expensive. This system has plants and roots suspended in the air, and below the plants are mist nozzles that spray the nutrient solution on the plants’ roots. It can look quite futuristic. These systems can often look like cubes or towers with the mist released at the top, and as the droplets cascade down, the roots of the plants get moisture and nutrients, but at the same time they can breathe well because they are surrounded by oxygen. This vertical structure means they take up less space, so you can have quite a number of towers in your house. You can also easily move an aeroponic tower to a different location. Aeroponics is an extremely clean and sterile way of growing. Roots can spread out as much as they want to because there isn’t any growing medium getting in their way.

 

In an Aeroponic system, the roots of plants are enclosed in a space known as aeroponic chamber. You can put the roots through holes that have flexible rubber collars—these are simple to use.

 

The plants get plenty of oxygen because they are suspended in the air. The reservoir which holds the water also contains an oxygenating air pump. The mist nozzles are connected to a water pump, and pressure causes the solution to be sprayed. If the plants have excess nutrients after being sprayed, these fall into a reservoir below them. You can grow most types of plants this way, but you’ll need a deeper reservoir for larger plants. Aeroponic systems use less water than other types of hydroponic systems. They can cost more to build, however. They also need a bit more maintenance than other systems. Sometimes you will find that the nozzles that spray the nutrient solution become clogged and will need cleaning.

 

Some growers who use this type of hydroponic system use a non-stop fine mist, while others will mist on a cycle. If it is on a cycle, there are only a few minutes between each cycle. They are much shorter than in Ebb and Flow systems discussed previously.

 

 

No growing medium is used in Aeroponic systems, so that can be a cost saving. The plants get plenty of access to oxygen because their roots are always suspended in the air. These systems use less water than any other type of hydroponics, and 95% less water than traditional gardening. In Aeroponic systems, plants grow really fast because they get so much oxygen, so it can be quite satisfying to see the rewards of caring for them and getting a good yield fast. 

 

The types of plants that do well in Aeroponic systems include tomatoes, lettuce, eggplants, watermelons, strawberries, bell peppers, ginger, baby greens, edible flowers, and herbs. Root vegetables, such as carrots and beets, don’t do well in these systems, and fruit trees are too large and heavy for Aeroponic systems. Plants may outgrow Aeroponic systems and may need to be transplanted elsewhere, so you may need to have alternative places if this occurs.

 

Aeroponic systems tend to be more expensive to set up than other hydroponic systems because you’ll need reservoirs, timers, pumps, misting nozzles, and more. If you have an Aeroponic system, you need to ensure that you frequently check timers and pumps so that your plants are misted properly because otherwise the roots would dry out and your plants would die. If you lose electricity, you’ll need to manually mist the plants with the nutrient solution to keep them moist. The root chambers will need cleaning to prevent diseases.

 

There are two pressure systems used in Aeroponics: low pressure system (LPA) and high pressure system (HPA). When you use a high-pressure system, the irrigation cycles are very short, usually 5 seconds every 5 minutes. When you are looking to purchase a pump for Aeroponics, you’ll have to consider not just the pump’s capacity (how many gallons of water it can move per hour) but its pressure power too—this is measured in pounds per square inch (PSI). 

 

If you’re interested in an Aeroponic system and it’s your first time doing this, you could buy a kit to get this set up easily.

 

Choosing the Right System for You

This will depend entirely on what your requirements are, whether you want to grow small or large plants, and whether you want to grow a large number of plants.

 

There really is a hydroponic system for everyone, depending on how much you want to spend, what space you have, and how technical you want it to be. You can use a jug and grow a sweet potato in it, or you can set up a space-age looking Aeroponic system if you have the time and money. 

 

If you are growing plants at home and want a fairly simple system that is easy to set up, then a wick or a DWC system are probably the easiest to start with. 

 

If you intend to grow a large number of plants, then you could look at Drip or NFT systems, but ensure that you thoroughly research the system you intend to use so that you’re aware of their advantages and disadvantages before starting.

 

You may need to give thought to how much space you have available, what your budget is for hydroponic gardening, what time you’ll have available to maintain and monitor it, and whether growing your own fresh produce all year round appeals to you. It is sensible to work out your budget before you start because if your budget is small, something like a Wick system may be a good plan, being one of the most inexpensive forms of hydroponics. DWC and NFT systems aren’t too expensive either, but they will require more maintenance. 

 

Whether you have any pre-existing experience with hydroponics is also something to consider. If you already have some experience with hydroponics, you could opt for something like an Ebb and Flow, NFT, or even Aeroponic system, whereas if you’re new to this, you may choose a Wick, DWC, or Drip system.

 

My personal favorite type of hydroponic system is the Drip system. While it’s a bit more complex than Wick or Deep Water Culture systems, it offers many advantages, such as being able to grow almost any plant, including larger ones. Drip systems are not too expensive to build, and you can easily scale them up to grow a much larger number of plants too. I still remember when I built our first Drip system, and one of my overriding memories is when we first grew a lot of pumpkins using this system. We made lots of wonderful produce from them, including pumpkin pies, spicy pumpkin soup, and honey roasted pumpkin seeds that were great as a healthy snack. We also carved our own pumpkins that we had grown for Halloween, and the house looked and smelled fantastic with the roasted pumpkin spiced smells and all these amazing glowing Jack-o'-lanterns!

 

For more great content check out the Proponics YouTube channel below!

 

Proponics on YouTube

 

 

By Max Barnes

Max Barnes is a long-time homesteader and author. Max grows the majority of his own food year-round using a variety of different methods, including hydroponics. Hydroponic gardening plays a huge part in his homestead and self-sufficiency goals.