Hydroponics is now widely used both domestically and commercially as the main alternative to growing plants in soil. Once again, the purpose of this section is to introduce you to the concepts available so you can get started on researching and designing your own system.
- Hydroponics requires no weeding and digging
- Faster and more productive growth than traditional growing methods
- Plants can be spaced much closer together (up to twice as dense) than planting in soil
- Minimal water usage – although more water is used than an aquaponics system because the water needs to be replaced
Disadvantages: Although less complicated than aquaponics, hydroponics still requires time and effort up front than conventional gardening methods. Higher set up cost than other methods, although you can use recycled materials to help reduce this. Regular maintenance and ongoing running costs required (nutrient solution, pump operation and maintenance).
Hydroponics is simply growing plants in a medium other that soil (inert mixture) with added nutrients. Systems typically consist of an immersed water pump in a tank that is mixed with nutrients. The pump is then used flow water through the grow beds and then the water nutrient mix drains back to the main tank.
Choosing a location and space
Hydroponics systems can also be set up pretty much anywhere outside that the space is available as long as there is enough sunlight hours in the day to enable the plants to grow. The alternative is to use grow lights, but this can become more expensive to run due to the demand on electricity. The advantage of hydroponics over aquaponics is that minimal space is required for the water storage, as you only need enough water to fill the space of the grow beds.
Different types of hydroponic systems
Flood and drain
As with the aquaponics flood and drain system, this hydroponics system uses a container filled with a grow media such as rockwool, coconut fiber or vermiculite for growing the plants. The container is filled with water combined with nutrient solution from the sump tank via a pump (immersed in the tank) usually connected to a timer. It is then drained back into the sump tank and the process is repeated to keep the system cycling and providing nutrients and water to the plants.
Electronic timer – stand pipe
A stand pipe is inserted vertically into the grow bed of the hydroponics system and the height is set the maximum water level in a grow bed. This pipe also acts as the drain pipe back into the tank. When the pump is switched off water drains slowly from the bed into the sump or fish tank through either the fill pipe or small holes that are drilled in the base of the standpipe. For a more detailed description of the stand pipe and other draining methods see the aquaponics section.
Nutrient Film Technique (NFT)
A good space saver, long custom made channels or PVC tubing with cut outs is used to house the plants in this hydroponics system. Plants can be inserted into baskets and then inserted into the main channel or pipe to immerse them in the water. One of the advantages of this type of system is that no grow media (other than air) is needed, making this a cheaper system to set up. The water / nutrient mix is continuously pumped through the channels/pipe and plant roots (no timer required) and then drains back into the sump tank. An air pump is added to the sump to help aerate the mix.
A word of warning here is that if the power does fail, it does not take long for the plants to become stressed and dry out – this is one of the disadvantages of this type of hydroponics system.
As with the N.F.T method and as the name indicates, the growing medium is air. The roots of the plants are suspended in air and are “misted” with nutrient solution via a pump submerged in the sump tank. A timer is used to turn the pump on in short cycles to keep up the moisture to the roots of the plants and may only be required to run for a few seconds every few minutes – saving on power costs. This is probably the most high tech method of hydroponics. This system has the same disadvantages as the N.F.T in the case of a power outage or pump failure.
The theory behind this method is that the plants growth is best when it has maximum access to oxygen resulting in optimum growth.
One of the most widely used systems for backyard gardeners; the drip system is a very basic setup of a pump immersed in a sump tank which then pumps water to plants via a drip system. A grow medium is used for the water/nutrient mix to drip into. The water can then either drain back into the sump similar to the flood and drain method where the system is continually cycled. Or alternatively it can be a non-draining system where the nutrient/water mix is used up be the plant and then replenished when needed. The advantage of the non-return system is that pH and nutrient mix is always stable (eg. What you put in the sump), whereas if the mix is drained back into the sump then pH and nutrient needs to be monitored and adjusted as needed.
Which system is best for you?
The methods described cover some of the more common ways that hydroponics is used. Once again, there are many other designs and concepts that build off these systems, so be creative and experiment when designing your own system to see what works best for your space and environment.
As with the aquaponics system, it is essential to have a pH testing kit as part of your hydroponics system, so you can monitor levels on a regular basis and adjust accordingly. Remember the optimum growing conditions for vegetables is slightly below neutral (7).
Continue to monitor pH levels within your hydroponics system to quickly react to changing conditions before the plants are affected.
Regular monitoring of the nutrient mix and water levels is required and the mix needs to be constantly replenished for optimum growth of your plants.
Enjoy experimenting with some simple hydroponics systems and compare the results with your conventional methods. You may find it is worth the extra time and effort.