Hydroponics presents a method of soilless agricultural production in system where the plants have a constant nutrient supply. In the recent years, these methods became quite popular in among different groups of people, whether they are just amateurs that want to produce fresh food in their homes or agricultural professional that want to utilize this method to set up a large-scale food production in environments that are usually not suitable for growing food.
Although its raising popularity, this method has been around for a long time, starting from the hanging gardens in Babylon and the floating gardens made by the Aztecs in Mexico up to the 1600s where real scientific discoveries are made regarding hydroponics by French and Belgium scientist.
The basic idea of hydroponics is to allow the plant to absorb the needed nutrients dissolved in water, making the root system no longer obliged to develop and all the energy is focused in developing the habitus of the plants, thus creating much larger densities, and producing higher yields in comparison to conventional production using soil as a medium.
Every automated hydroponic system is made from several components. Here is a basic list of components that need to be implemented in order to create one hydroponic system, no matter if it is a home setup or high-tech large-scale commercial setup.
Firstly, you will need a growing chamber. Under the term growing chamber is everything that can holds water and have enough room to allow the root system to develop properly. Later in the text when we are going to describe the different methods and scales of hydroponic production, you’ll get familiar what can be used for a growing chamber.
Secondly, going in a logical order, is the reservoir where water and nutrients are getting mixed allowing the nutrient solution to be pumped in a circular way. Take into account that a proper reservoir should be made out of lightproof material. By making this decision you are going to solve a several problems, regarding the presence of overpopulated microorganisms and algae.
Next on the list is the air pump that will keep the water oxygenated, one of the crucial factors whether your production will succeed or not.
And the last essential thing on the list is the delivery system. There is a broad range of methods and materials to do this and one of the most practical one is the implementation of PVC pipes system.
As addition to this set of things, to make the system more autonomous and effective is the implementation of timers and artificial lights. The timers would provide you with an extra free time and less chores that you can use to focus on other things, such the crop itself, and the artificial lights will boost the photosynthetic activity of the plants ensuring maximum utilization of the specific crop yield potential.
Type of systems in modern hydroponic production
Dozens of systems are developed throughout the years. Some of them are passive like the Wick system and the large portion of them are active systems, which means they use pumps and gravitational force to provide constant moving of the nutrient solutions within the systems. The Wick system use different material as wicks (rayon, polyester, nylon and more) to provide the nutrient solution to the root system of the plants via capillary way.
The following systems belong to the active group of hydroponic production.
- Dutch bucket method
System built from special buckets, drainpipes, and a reservoir. The buckets are designed in such a way that they can be mounted on the drainpipes. This system is suitable for hobbyists but also for commercial grow (highly depend on the crops that are intended to be grown), since the Dutch bucket method requires usage of coarser medium such as expanded clay or perlite. The reason that a coarser medium is being used is that the plants need to have more solid and rigid medium for the root system to hold on something. Fun fact about this system: it is only called Dutch because the buckets where predominantly made in Holland.
- Ebb and flow system
This is a really suitable method for setting up a hydroponic farm at home (the detailed instructions will be presented later in the article). Works on a principle “flood and drain” where on predefined frequency the water pump will flood the growing chamber allowing for the nutrient solution to be spread evenly among the plants. When the solution reach a certain level a drain pipe bring the solution back to the reservoir where is additionally mixed and oxygenized for the next flooding. This method is very popular among the gardeners and many of the pre-made systems that are commercially available use this method. Popular mediums in this system are expanded clay pebbles, rockwool and perlite.
- Top feed (Drip system)
The name of the system clearly explains the principles of such hydroponic farm. This system is particularly good for growing crops with larger habitus because every crop is planted in a separate pot. A drip line, starting from the reservoir, is extended to each pot where on a regular basis the water pump delivers a certain amount of nutrient solution. The excess solution is drained from the pot in a channel that return the solution to the reservoir with the help of the gravity. Some of the systems may not have channels that brings the water back to the reservoir but instead the water pump is pumping a precise amount of solution to suit the needs of the crops and keep the medium wet until the next pumping.
It is out of a great importance that the quantity of the distributed solution must be very precise. Insufficient liquid between the scheduled irrigation may irreversibly dry out the roots of the crops and you will have an unsuccessful production, a nightmare for every grower, no matter if you are a professional having a fully automated hydroponic farm or an ambitious amateur having an improvised hydroponic farm setup at home. In a fully automated hydroponic farm this can be out of great use both practical and financially because this setup does not need the distribution channels to the reservoir, at the same time saving precious amounts of water. Also implementing such technique requires constant monitoring control of the nutrients level in the solution.
- Nutrient Film Technique
Also, very popular method of hydroponic farming where enclosed V-shape channel is used for crop planting. This channel is also tilted down to create natural gravity driven pathway for the excess nutrient solution. The pump needs to be running constantly providing a constant flow of nutrient solution forming a film. Nutrient Film Technique is very suitable for growing plants that are small, like lettuce and various herbs. It can be implemented on a large-scale operation where high-level of automation is needed because the plants can be susceptible to suffocation or wilting if the system is not working properly as a result of malfunction or power outage. This system requires a hydroponic CO2 controller.
- Raft method
One of the most utilized methods for large-scale lettuce or other greens production. The growing chamber has larger dimensions than other types of hydroponic farm systems because it needs to hold larger amounts of water allowing the polystyrene rafts to freely float around. With the help of the water pump a stream is made helping the rafts to move along the chamber. This is particularly helpful on larger scales allowing the producers to improve their effectiveness in doing operational activities. The air pumps must work impeccably to prevent one of the most frequent problems in this kind of production, the stagnation of the water and suffocations of the crops.
Aeroponic way of production is simply suspending the crop in midair while constantly supplying them with the needed nutrients via mist, maintaining 100% humidity. One of the greatest characteristics of the system is that the roots are provided with maximum oxygen, allowing production of healthy and fresh produce. Because of the complexity of the system, both financially and operationally this method is mostly used in laboratory for research purposes. Major anomaly of the system is the failure of the misting nozzles and the water pump, resulting in rapid crop loss.
Type of growing mediums used in hydroponic farms
On the market you will find many different growing mediums that can be used in hydroponic farming. In this part of the article, we are going to discuss the most popular substrates that have proved their effectiveness as a substitute of the “original” soil. Nonetheless of what material they have been produced, every medium needs to be inert, light weight, lightproof and porous.
The main function of the mediums is to provide support for the growing crops and to minimize the amount of light that can penetrate in the root system. Because of their inertness, they do not interfere with the provided nutrient solution, thus allowing full utilization of the prepared solution.
The most popular mediums in hydroponic farming, either that is home setup or commercial production, are the following.
In the process of melting basal rock a rockwool fibers are made and when it is pressed, we get the familiar looking product that can be in a shape of cubes, bricks, or slabs. Rockwool is ideal for seed germination because of its resistance to microbe development, good aeration, and absorption capacity. It is known that can cause skin and lung irritation and it is not environmentally friendly. Every grower must regularly check the pH because the rockwool has the ability of pH altering.
Expanded clay pellets
Expanded clay pellets original name is LECA (Lightweight Expanded Clay Aggregate) and it is made in a process similar to the process of making popcorn. The clay is heated to a certain degree, similar like the process of perlite production, until it expands into the known round shape. It has very good drainage capacity and it is pH neutral. The clay pellets can be reused lot of times, they need a just good thorough washing before usage. It is advisable to mix the clay pellets with another medium that has good water retention capacity (only major disadvantage of this medium).
Naturally occurring material or more specifically volcanic glass that has the ability to expand 20 times larger than its original size if heated to certain point. It is highly porous which provide excellent aeration and drainage for the crops and often is mixed in an equal ratio with vermiculite. One of the main disadvantages of this medium is his dust, causing irritation to the respiratory system when handling.
Organic fibers that are byproduct of the coconut industry that have excellent water and air retention properties. It is often sold as blocks with smaller dimension, but when water is added they can swell up to 8 time of their original size. This medium can be reused three to four times before starting to breakdown and because of his breakdown tendency it is not suitable for ebb and flow system. If you want a perfect medium, it is advisable to mix the coconut coir with other mediums that have good drainage properties.
Vermiculite is an expanded mineral that goes under the same process as the clay pellets and the perlite. It greatly retains water without altering the pH. It is often used in a mix with other mediums providing excellent environment for successful production. This medium does not break up and after proper cleaning it can be reused.
Needed equipment for environmental control
The type of equipment is dependent whether you want to set up a hydroponic farm at home or an automated hydroponic farm for commercial use. If you decide to begin with the backyard hydroponic farm almost every needed item you can obtain from a local building suppliers or distributors of plumbing, electrical and heating equipment, other than an environment controller. If you decide to take this on a professional level, you need to find a specialized company for greenhouse hydroponic constructions.
Nonetheless, in every type or scale of production you will need to focus on regulating the following environmental and technical parameters.
There is a whole industry solely focused on controlling the temperature in closed agricultural production. The temperature needs to be two-way controlled, by cooling and heating depending on the time of the year or more precisely on the time of the day. Under the temperature control there is a need for implementation of heating, cooling and ventilation systems.
Heating systems can range from simple electrical heaters to specialized heating mats that are placed under the crops.
Cooling systems can be either evaporative cooling, fogging systems or specialized high-tech systems for commercial growing.
Ventilation is straightforward when comes to closed production. You will need exhaust and circulation fans.
All the above-mentioned systems cannot be properly used if you do not have a proper control over them. For controlling these systems an additional equipment is needed such as thermometers and humidity meters.
Additional supplementary light is always needed in order to provide optimal conditions for the plants which will ultimately result in maximum yield and shortening of the growing period. The choice of light is a function of light demand of the specific crops, capital cost, operational cost, and the area served by a given unit. The type of the lightning system is a matter of personal choice and the scale of the hydroponic farm. They can range from cool white, high-output fluorescent, high intensity discharge (HID), light emitting diode (LED), and compact fluorescent lights.
Also, for this lightning equipment controllers are needed to mimic the light period needed. Almost every crop group demands different light schedule but mostly it is ranging from 12-14 hours of light. This can be controlled with the help of timers or photo sensors.
In hydroponic production irrigation is everything. The most important thing is to have automated growing system that are partly or fully autonomous. Apart from the irrigation system for providing nutrient solution to the crops an additional equipment is needed. This means that you will need pH and EC meters, water temperature meters and nutrient level meters.
These conditions must be held on optimal or sub-optimal level in order to prevent any damage to the crops which will result in yield and financial loss. Controlling all the above-mentioned parameters can sometimes be exhausting and time-consuming but thankfully the nowadays technology allows us to enjoy in hydroponic production while being fully informed and fully in-control of the growth and environmental factors in the hydroponic farm. And the control is available through specially developed software applications on your smartphone, tablet, or computer. If you want your hydroponic farm to be fully automated, you should seek all-in-one controller that have compatible sensor kits.
Hope this article has provided you enough knowledge and insight in the beautiful journey in hydroponic production.