Growing Systems

BUYERS GUIDE

Hydroponic Systems Buyers Guide

One of the greatest aspects of hydroponics is the versatility in growing methods. There are hundreds of ways to grow hydroponically and new techniques are surfacing all of the time. However, out of all the current techiniques, every method is usually a variation or a combination of the following hydroponics systems.


Nutrient film technique (NFT)

NFT is one of the most commonly used hydroponic systems and it works in a beautifully simple way. Unlike many other hydroponics systems that need a timer to control the delivery of a nutrient solution, the NFT method constantly pumps the nutrient solution throughout the system, eliminating the risk of timer failure.

NFT works by placing a nutrient solution in a reservoir tank and placing plants in long sloped channels above the reservoir tank. A thin film of nutrient solution is pumped into one end of the channel and flows under the force of gravity down the slope over the roots. Any excess solution flows through a hole at the other end of the channel and back into the reservoir tank to be re-used.

A typical NFT system uses no growing medium at all. The channel usually houses plant pots on a piece of corrugated plastic, suspending them over the base of the channel where the solution flows. This prevents any light getting to the roots and stops the build-up of algae. The tips of the roots hang down into the constant flow of nutrient solution, allowing the plants to absorb what they need when they need it.

This set-up works well because plants have direct access to nutrients as and when they need them. Plus, as the roots aren’t contained in a growing medium they have access to the oxygen they need straight from the air around them, which helps facilitate faster and healthier growth.

Advantages of NFT
  • Efficient use of water and nutrients with little waste
  • Easy to harvest when using no growing medium for NFT
  • Easy to check the roots for signs of problems or disease
Disadvantages of NFT
  • Any failure in the system (e.g. pump failure) will have an immediate effect on plant health
  • Large plants can lack support as the roots are not grounded in any growing medium
  • As the nutrient solution flows down the channel uneven growth can occur
Our verdict

NFT has its charms and its setbacks. When nothing goes wrong, it is one of the most productive hydroponic systems out there. However, as it often involves exposing the roots in air, it is also one of the least forgiving systems when problems arise. That being said, many of the growers that have used NFT successfully tend to stick with it over other hydroponic techniques.

Check out our NFT systems.

Flood and drain

Flood and drain systems (also known as “ebb and flow” systems) are made up of a reservoir (which holds the nutrient solution) and a grow tray (that houses the plants).  The system functions by temporarily pumping the nutrient solution from the reservoir into the grow tray, flooding the root zone of plants with the nutrition they need, before draining the solution back into the reservoir.

A timer usually operates a submerged pump, which floods and drains the grow tray at specific intervals during a given day. The actual number of times the system floods and drains in a day should be tailored to the size and type of plants you are growing. Temperature and humidity should also be taken into account. Although the frequency of flooding and draining will vary, most systems usually flood the root zone for around 15 – 20 minutes before draining back into the reservoir.

An overflow measure is often implemented into flood and drain systems to prevent over-flooding the grow tray. This is usually a simple tube that drains the water back into the reservoir tank once it reaches a certain height. A range of growing mediums can be used with flood and drain systems, but the most suitable are coco, clay pebbles, vermiculite, and perlite (which are good at retaining water). It is possible to use a flood and drain system with no media whatsoever, but this will increase the risk of the roots drying out if the pump or timer fails, as there is no medium to retain water.

Advantages of flood and drain
  • Flooding prevents build-up of salt in the root zone and helps achieve uniform conductivity and PH
  • Flooding removes oxygen deficient air from the root zone and draining draws fresh oxygen rich air back into the root zone
  • Dry periods between flooding can encourage the growth of a robust root structure which is beneficial for nutrient uptake and plant development
Disadvanatages
  • In systems where no medium is used, any failure (such as pump or timer failure) can cause plants to die in a matter of hours
  • Height of the reservoir and tray can limit the overall height of your plants
Our verdict

One of the greatest features of flood and drain systems is their versatility. You can successfully use a variety of growing mediums with the flood and drain technique or even no medium at all, which means you have plenty of possibility for experimentation to find a set-up that best suits you. Probably the biggest drawback of flood and drain is that you’ll always need to be on hand to pay close attention to your system, as one little blip can kill your plants off rapidly.

Check out our flood and drain systems.

Drip system

The drip system is a widely used and relatively simple hydroponics growing technique. In a drip system, a timer is used to control a submersed pump, which when turned on, pumps a nutrient solution from a reservoir tank directly onto the root mass of individual plants via a drip line. The drip line is usually comprised of a main tube that pumps the nutrient solution direct from the reservoir, and smaller ‘dripper lines’ which drip the solution onto each individual plant.

The two types of drip system that are usually used in hydroponic gardening are recovery systems and non-recovery systems. The recovery system is a closed system in which excess nutrient solution that isn’t used by the plants is recycled into the reservoir for re-use. The non-recovery system is an open system where excess nutrient solution is discarded after use and not recycled back into the reservoir tank.

Recovery vs non-recovery systems

As recovery systems use recirculated nutrient solution, they are slightly more efficient and less wasteful than non-recovery systems. However, recovery systems will require higher levels of maintenance than non-recovery systems to sustain a balanced nutrient solution. This is because fluctuations in PH and electrical conductivity levels occur as the plants will have absorbed some of the nutrients before they are recycled back into the reservoir.

Non recovery systems may be more wasteful but they require less maintenance as the nutrient solution in the reservoir remains balanced, and PH and electrical conductivity levels only need to be monitored when new solution is added to the tank. However, a more precise timer is sometimes required in non-recovery systems to ensure that run-off is kept to a minimum.

Advantages of drip systems
  • Often simple to set-up
  • Easy to maintain correct nutrient levels in a non-recovery system
  • Nutrients are delivered direct to the roots, limiting energy expenditure of plants
  • After initial set-up costs drip systems are relatively inexpensive to maintain
Disadvantages of drip systems
  • Initial set-up can be expensive
  • Drippers are renowned for clogging, especially when using organic nutrients
  • As the solution is dripped onto a specific area, problems can arise with moisture distribution
Our verdict

Drip systems are an effective method of growing plants hydroponically, especially if you can avoid the clogging that is often associated with this type of system. We will always recommend a drip system over hand watering and feeding. However, because of the associated clogging, other systems like NFT can be less problematic. If you do decide to use a drip system, then we recommend using a non-recovery system with clay pebbles for easier maintenance and for keeping balanced nutrient levels to help your plants flourish.

Check out our drip systems.

Deep Water Culture (DWC)

Deep Water Culture (DWC) systems are one of the simplest hydroponic growing techniques, and many growers consider DWC to be the “purest form of hydroponics.” The system involves suspending plants in an oxygenated, nutrient-rich solution. The main components of a DWC system are a container (to hold the nutrient solution), a lid, a net pot, and an aquarium air pump with an air stone to oxygenate the nutrient solution.

In a DWC system, the plant roots are submerged in the nutrient solution held in the container and the rest of the plant is held in suspension above the nutrient solution by the net pot, which usually sits in the middle of the container lid. The net pot allows for the roots to grow out into the nutrient solution, whilst the air pump and air stone ensure that enough oxygen is pumped into the solution to aerate the root zone.

DWC systems require very little maintenance. There is no need for a timer to control delivery of the nutrient solution and no need for a timer or controller to operate the air pump; as the pump needs to remain on 24/7 to ensure adequate oxygenation and to prevent the roots from drowning.

As DWC systems are relatively simple systems, some growers prefer to create their own DIY version. However, we highly recommend buying a ready-made DWC system to avoid issues with algae growth and light penetrating through to the plant roots.

Advantages of DWC systems
  • No drip or spray emitters mean no risk of clogging
  • Less fertiliser is needed as plants are constantly suspended in the nutrient solution
  • Highly oxygenated solution encourages healthy root development and overall plant growth
  • Easy to maintain and no need for timers and controllers
Disadvantages of DWC systems
  • Air pump failure will cause the roots to drown and can lead to rapid plant death
  • Without water chillers it can be difficult to maintain the optimum temperature range
  • The design of DWC systems can make checking the roots tricky, especially with large plants
  • As plants are constantly in the nutrient solution, PH and electrical conductivity (EC) levels will vary greatly and will need regular monitoring.
Our verdict

DWC systems do require high levels of maintenance, which can be inconvenient for some growers. PH and EC levels can fluctuate rapidly so regular monitoring is a necessity to ensure you maintain a balanced system. However, those willing to put the effort in will see the fruits of their labour, as DWC systems not only reduce growing times, but they are also one of the most productive hydroponics systems out there.

Aeroponics

Aeroponics could be considered the most advanced form of hydroponic gardening to date. Like regular hydroponics, soil is not required and all nutrients are delivered through water and water alone. However, unlike other hydroponics systems, in aeroponics the nutrient-rich water solution is delivered as a mist.

The basic set-up of an aeroponics system involves growing plants in a closed or partially closed environment. The plants are suspended in the air and the roots are sprayed every few minutes with a nutrient-rich mist. Like NFT and DWC growing methods, the roots need to be shielded from light to prevent damage and most aeroponics set-ups look similar to both of these methods.

A timer controls the delivery of the nutrient solution, which, unlike conventional hydro systems, needs to be a short cycle timer and set to mist the plants for several seconds every few minutes to prevent the roots from drying out.  The mist needed in an aeroponics system is usually supplied by either a fine spay nozzle or a pond fogger.
Due to the fact roots can die off extremely quickly without water, many growers choose to combine aeroponics growing techniques with regular hydroponics; using a back-up hydro system such as DWC to rescue plants should the aeroponics system fail.

Advanatages of aeroponics
  • High oxygenation at the root zone encourages plants to grow faster and healthier
  • Efficient use of water and nutrients means less is needed and less is wasted
  • Aeroponics systems are relatively easy to maintain
Disadvantages of aeroponics
  • Any failure in the pump, sprayer, or timer can result in rapid deterioration of plant health and death
  • Requires technical knowledge as plant nutrients need to be carefully administered
  • Currently effective aeroponics system aren’t cheap and initial set-up costs can be expensive
Our verdict

Aeroponics can be an effective way to grow plants, and it is definitely the most efficient method of growing plants without soil, using less water and nutrients than other hydroponic techniques. However, current aeroponics technology is primarily geared at the commercial market and there aren't many systems out there to accomodate hobby growers. Personally, we prefer using a DWC or NFT system, as they are extremely productive and there are great systems on the market for both the commercial and hobby grower.

Check out our aeroponics systems.

Wick system

The wick system is undoubtedly the simplest type of hydroponics system. Nutrient solution is drawn from a reservoir into the growing medium with a wick. It is known as a passive hydroponics system, which means there are no active parts and no electricity is needed to pump nutrients from the reservoir to the growing medium.

Instead, wick systems work through capillary action, whereby the wick acts as a delivery mechanism for nutrients. A highly absorbent lower end sits in a reservoir filled with nutrient solution. The other end is fixed near the plant root system in the growing medium. The more nutrient solution plant roots absorb, the more is pulled through the wick from the reservoir into the growing medium.

A whole host of growing media can be used with the wick system, although it is commonly used with Perlite, Vermiculite, Clay Pebbles, and Coco. Many growers choose a medium that will provide good aeration and oxygenation at the root zone, and many choose to supplement the reservoir with an air pump and airstone to ensure more air is transported through the wick to the roots.

Advantages of wick systems
  • Very inexpensive to set-up, all you need is growing media, reservoir, and wicks
  • Extremely simple system, you can easily build your own in a short space of time
Disadvantages of wick systems
  • No control over rate and frequency of irrigation
  • Constant supply of water makes the system more susceptible to fungal infestations
  • Constant supply of water can be harmful to some plants and will stunt growth
  • Dirty system and wicks are susceptible to mould and other harmful bacteria
  • Can cause root rot in set-ups that don’t use a medium with good aeration
  • Larger plants may not get adequate nutrients or water fast enough from the wick
Our verdict

The wick system is incredibly easy to set-up and due to its low cost; it can be a potential option for beginners or those curious about how such a system works. However, wick systems are the least used of all hydroponics systems because they simply carry too many risks and apart from the cost and set-up, they offer little in the way of benefits. Wick systems are unclean and increase chances of root rot and other diseases.

We don’t sell wick systems for the simple fact that much better systems exist. If you do choose to use a wick system, make sure you use a growing medium that provides good aeration and steer clear of growing large plants and plants that don’t respond well to over watering.


© 2003 - 2014, Green's Horticulture, All Rights Reserved. | Affiliate Program