HYDROPONICS

                                                               HYDROPONICS

By-Sanket Kumar Sahu
Brahmapur,Odisha

Hydroponics is a subset of Hydroculture, which is a method of growing plants without soil by using mineral nutrient solutions in a water solvent.Terrestrial plants may be grown with only their roots exposed to the mineral solution, or the roots may be supported by an inert medium, such as perlite or gravel.

TYPES OF HYDROPONICS SYSTEM

There are two main variations for each medium, sub-irrigation and top irrigation. For all techniques, most hydroponic reservoirs are now built of plastic, but other materials have been used including concrete, glass, metal, vegetable solids, and wood. The containers should exclude light to prevent algae growth in the nutrient solution.

Hydroponic systems are characterized as active or passive. An active hydroponic system actively moves the nutrient solution, usually using a pump. Passive hydroponic systems rely on the capillary action of the growing medium or a wick. The nutrient solution is absorbed by the medium or the wick and passed along to the roots. Passive systems are usually too wet and do not supply enough oxygen to the root system for optimum growth rates.

Hydroponic systems can also be characterized as recovery or non-recovery. Recovery systems or recirculating systems reuse the nutrient solution. Non-recovery means just what it says. The nutrient solution is applied to the growing medium and not recovered.

Based on techniques used hydroponic systems can be divided in following 6 types: Wick, Water Culture, Ebb and Flow (Flood & Drain), Drip (recovery or non-recovery), N.F.T. (Nutrient Film Technique) and Aeroponic. There are hundreds of variations on these basic types of systems, but all hydroponic methods are a variation (or combination) of these six.

1. WICK SYSTEM


This system can use a variety of growing medium. Perlite, Vermiculite, Pro-Mix and Coconut Fiber are among the most popular.The Wick system is by far the simplest type of hydroponic system. This is a passive system, which means there are no moving parts. The nutrients are stored in the reservoir and moved into the root system by capillary action often using a candle or lantern wick. In simpler terms, the nutrient solution travels up the wick and into the root system of the plant.

The wick system is easy and inexpensive to set-up and maintain. Although, it tends to keep the growing medium to wet, which doesn’t allow for the optimum amount of oxygen in the root system. The wick system is not the most effective way to garden hydroponically.

The biggest drawback of this system is that plants that are large or use large amounts of water may use up the nutrient solution faster than the wick(s) can supply it.

2.WATER CULTURE SYSTEM



Water culture is the system of choice for growing leaf lettuce, which are fast growing water loving plants, making them an ideal choice for this type of hydroponic system. Very few plants other than lettuce will do well in this type of system.

This type of hydroponic system is great for the classroom and is popular with teachers. A very inexpensive system can be made out of an old aquarium or other water tight container. The biggest drawback of this kind of system is that it doesn’t work well with large plants or with long-term plants.

3. EBB & FLOW SYSTEM – (FLOOD AND DRAIN)

The Ebb and Flow hydroponic system is an active recovery type system. The Ebb and Flow uses a submersible pump in the reservoir and the plants are in the upper tray. They work on a simple flood and drain theory. The Ebb and Flow system works by temporarily flooding the grow tray with nutrient solution and then draining the solution back into the reservoir. This action is normally done with a submerged pump that is connected to a timer. The reservoir holds the nutrient solution and the pump.

When the pump turns on, the nutrient solution is pumped up to the upper tray and delivered to the root system of the plants. The pump should remain on for about 20 to 30 minutes, which is called a flood cycle. Once the water has reached a set level, an overflow pipe or fitting allows the nutrient solution to drain back into the reservoir. The pump remains on for the entire flood cycle. After the flood cycle the nutrient solution slowly drains back down into the reservoir through the pump. During the flood cycle oxygen poor air is pushed out of the root system by the upward moving nutrient solution. As the nutrient solution drains back into the reservoir, oxygen rich air is pulled into the growing medium. This allows the roots ample oxygen to maximize their nutrient intake.The Timer is set to come on several times a day, depending on the size and type of plants, temperature and humidity and the type of growing medium used.The Ebb & Flow is a versatile system that can be used with a variety of growing mediums. The entire grow tray can be filled with Grow Rocks, gravel or granular Rockwool. Many people like to use individual pots filled with growing medium, this makes it easier to move plants around or even move them in or out of the system.

The main disadvantage of this type of system is that with some types of growing medium (Gravel, Growrocks, Perlite), there is a vulnerability to power outages as well as pump and timer failures. The roots can dry out quickly when the watering cycles are interrupted. This problem can be relieved somewhat by using growing media that retains more water (Rockwool, Vermiculite, coconut fiber or a good soilless mix).

The Ebb and Flow is low maintenance, yet highly effective type of hydroponic gardening.

4.DRIP SYSTEMS RECOVERY / NON-RECOVERY


Drip systems are probably the most widely used type of hydroponic system in the world.Operation is simple; a timer controls a submersed pump. The timer turns the pump on and nutrient solution is dripped onto the base of each plant by a small drip line. In a Recovery Drip System the excess nutrient solution that runs off is collected back in the reservoir for re-use. The Non-Recovery System does not collect the run off.The Continuous Drip system is an active recovery or non-recovery type system. This system uses a submersible pump in a reservoir with supply lines going to each plant. With drip emitter for each plant the gardener can adjust the amount of solution per plant. A drip tray under each row of plants, sending the solution back to the reservoir, can easily make this system an active recovery type. In the early days of hydroponics, the extra solution was leached out into the ground. Continuous Drip systems are often used with Rockwool. Although, any growing medium can be used with this system, thanks to the adjustment feature on each individual drip emitter.

A recovery system uses nutrient solution a bit more efficiently, as excess solution is reused, this also allows for the use of a more inexpensive timer because a recovery system doesn’t require precise control of the watering cycles. The non-recovery system needs to have a more precise timer so that watering cycles can be adjusted to insure that the plants get enough nutrient solution and the runoff is kept to a minimum.

The non-recovery system requires less maintenance due to the fact that the excess nutrient solution isn’t recycled back into the reservoir, so the nutrient strength and pH of the reservoir will not vary. This means that you can fill the reservoir with pH adjusted nutrient solution and then forget it until you need to mix more. A recovery system can have large shifts in the pH and nutrient strength levels that require periodic checking and adjusting.

5.N.F.T. (Nutrient Film Technique)

The Nutrient Film Technique or NFT system is an active recovery type hydroponic system.The plants are held up by a support collar or a grow-basket and no growing medium is used. There is usually no growing medium used other than air, which saves the expense of replacing the growing medium after every crop. Plant is supported in a small plastic basket with the roots dangling into the nutrient solution.This is the kind of hydroponic system most people think of when they think about hydroponics. N.F.T. systems have a constant flow of nutrient solution so no timer required for the submersible pump. The nutrient solution is pumped into the growing tray (usually a tube) and flows over the roots of the plants, and then drains back into the reservoir. The nutrient solution flows over the roots up to 24 hours per day.

Oxygen is needed in the grow-tube so capillary matting or air stones must be used. The NFT system is very effective. Although, many novice hydroponic growers find it difficult to fine tune. N.F.T. systems are very susceptible to power outages and pump failures. The roots dry out very rapidly when the flow of nutrient solution is interrupted. It can also be very unforgiving, with no growing medium to hold any moisture, any long period of interruption in the nutrient flow can cause the roots to dry out and the plants to suffer and possibly die.

6.AEROPONIC SYSTEM

A timer controls the nutrient pump much like other types of hydroponic systems, except the aeroponic system needs a short cycle timer that runs the pump for a few seconds every couple of minutes.The aeroponic system is probably the most high-tech type of hydroponic gardening. Like the N.F.T. system above the growing medium is primarily air. The roots hang in the air and are misted with nutrient solution. The mistings are usually done every few minutes. Because the roots are exposed to the air like the N.F.T. system, the roots will dry out rapidly if the misting cycles are interrupted.

In this system, plant roots are misted with water and nutrients, while getting oxygen directly from the air. Aeroponics has been proven and refined for decades and is used by scientists around the world, including NASA. Using Aeroponics, plants:

• receive their required daily nutrients.
• avoid contact with soil borne pests and fungus.
• grow up to 50% faster.

The opportunity to grow fresh fruits and vegetables outside of the soil, indoors or outdoors, is becoming not only a distinct advantage, but also a necessity. While we have learned much about this exciting method of growing, the benefits of Aeroponics are still largely untapped. It is believed that Aeroponics will soon be the most commonly used growing technique worldwide.

ADVANTAGES & DISADVANTAGES OF HYDROPONICS

1. No Soils Needed

In a sense, you can grow crops in places where the land is limited, doesn't exist, or is heavily contaminated. In the 1940s, Hydroponics was successfully used to supply fresh vegetables for troops in Wake Island, a refueling stop for Pan American airlines. This is a distant arable area in the Pacific Ocean. Also, Hydroponics has been considered as the farming of the future to grow foods for astronauts in the space (where there is no soil) by NASA.

2. Make Better Use Of Space And Location

Because all that plants need are provided and maintained in a system, you can grow in your small apartment, or the spare bedrooms as long as you have some spaces.Plants' roots usually expand and spread out in search of foods, and oxygen in the soil. This is not the case in Hydroponics, where the roots are sunk in a tank full of oxygenated nutrient solution and directly contact with vital minerals. This means you can grow your plants much closer, and consequently huge space savings.

3. Climate Control

Like in greenhouses, hydroponic growers can have total control over the climate - temperature, humidity, light intensification, the composition of the air. In this sense, you can grow foods all year round regardless of the season. Farmers can produce foods at the appropriate time to maximize their business profits.

4. Hydroponics Is Water-Saving

Plants grown hydroponically can use only 10% of water compared to field-grown ones. In this method, water is recirculated. Plants will take up the necessary water, while run-off ones will be captured and return to the system. Water loss only occurs in two forms - evaporation and leaks from the system (but an efficient hydroponic setup will minimize or don't have any leaks).

It is estimated that agriculture uses up to 80% water of the ground and surface water in the US. While water will become a critical issue in the future when food production is predicted to increase by 70% according to the FAQ, Hydroponics is considered a viable solution to large-scale food production. 

5. Effective Use Of Nutrients

In Hydroponics, you have a 100% control of the nutrients (foods) that plants need. Before planting, growers can check what plants require and the specific amounts of nutrients needed at particular stages and mix them with water accordingly. Nutrients are conserved in the tank, so there are no losses or changes of nutrients like they are in the soil. 

6. pH Control Of The Solution

All of the minerals are contained in the water. That means you can measure and adjust the pH levels of your water mixture much more easily compared to the soils. That ensures the optimal nutrients uptake for plants. 

7. Better Growth Rate

Is hydroponically plants grown faster than in soil? Yes, it is.

You are your own boss that commands the whole environment for your plants' growth - temperature, lights, moisture, and especially nutrients. Plants are placed in ideal conditions, while nutrients are provided at the sufficient amounts, and come into direct contacts with the root systems. Thereby, plants no longer waste valuable energy searching for diluted nutrients in the soil. Instead, they shift all of their focus on growing and producing fruits.

8. No Weeds

If you have grown in the soil, you will understand how irritating weeds cause to your garden. It's one of the most time-consuming tasks for gardeners - till, plow, hoe, and so on. Weeds are mostly associated with the soil. So eliminate soils, and all bothers of weeds are gone. 

9. Fewer Pests & Diseases

And like weeds, getting rids of soils helps make your plants less vulnerable to soil-borne pests like birds, gophers, groundhogs; and diseases like Fusarium, Pythium, and Rhizoctonia species.Also when growing indoors in a closed system, the gardeners can easily take controls of most surrounding variables.

10. Less Use Of Insecticide And Herbicides

Since you are using no soils and while the weeds, pests, and plant diseases are heavily reduced, there are fewer chemicals used. This helps you grow cleaner and healthier foods. The cut of insecticide and herbicides is a strong point of Hydroponics when the criteria for modern life and food safety are more and more placed on top.

11. Labor And Time Savers

Besides spending fewer works on tilling, watering, cultivating, and fumigating weeds and pests, you enjoy much time saved because plants' growth is proven to be higher in Hydroponics. When agriculture is planned to be more technology-based, Hydroponics has a room in it.

12. Hydroponics Is A Stress-Relieving Hobby

This interest will put you back in touch with nature. Tired after a long working day and commute, you return to your small apartment corner, it's time to lay back everything and play with your hydroponic garden. Reasons like lack of spaces are no longer right. You can start fresh, tasty vegetables, or vital herbs in your small closets, and enjoy the relaxing time with your little green spaces.

Seem like there are lots of benefits of Hydroponics and the image below seems to try to persuade you into Hydroponic growing. But keep reading to learn about its downsides.

Disadvantages and Challenges:

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DISADVANTAGES

13. A Hydroponic Garden Requires Your Time And Commitment

Just like any things worthwhile in life, hard-working and responsible attitude gives satisfactory yields. However, In soil-borne counterparts, plants can be left on its own for days and weeks, and they still survive in a short time. Mother nature and soils will help regulate if something is not balancing. That's not the case in Hydroponics. Plants will die out more quickly without proper care and adequate knowledge. Remember that your plants are depending on you for their survival. You must take good care of your plants, and the system upon initial installation. Then you can automate the whole thing later, but you still need to gauge and prevent the unexpected issues of the operations, and do frequent maintenance.

14. Experiences And Technical Knowledge

You are running a system of many types of equipment, which requires necessary specific expertise for the devices used, what plants you can grow and how they can survive and thrive in a soilless environment. Mistakes in setting up the systems and plants' growth ability in this soilless environment and you end up ruining your whole progress.

15. Organic Debates

There have been some heated arguments about whether Hydroponics should be certified as organic or not. People are questioning whether plants grown hydroponically will get microbiomes as they are in the soil. But people around the world have grown hydroponic plants - lettuces, tomatoes, strawberries, etc. for tens of years, especially in Australia, Tokyo, Netherland, and the United States. They have provided food for millions of people. You cannot expect perfection from anything in life. Even for soil growing, there are still more risks of pesticides, pests, etc. compared to Hydroponics. There are some organic growing methods suggested for Hydroponic growers. For example, some growers provide microbiomes for plants by using organic growing media such as coco coir and add worm casting into it. Natural-made nutrients are commonly used such as fishes, bones, alfalfas, cottonseeds, neems, etc.

16. Water And Electricity Risks

In a Hydroponic system, mostly you use water and electricity. Beware of electricity in a combination of water in close proximity. Always put safety first when working with the water systems and electric equipment, especially in commercial greenhouses.

17. System Failure Threats 

You are using electricity to manage the whole system. So suppose you do not take preliminary actions for a power outage, the system will stop working immediately, and plants may dry out quickly and will die in several hours. Hence, a backup power source and plan should always be planned, especially for great scale systems.

18. Initial Expenses

You are sure to spend under one hundred to a few hundreds of dollars (depending on your garden scale) to purchase equipment for your first installation. Whatever systems you build, you will need containers, lights, a pump, a timer, growing media, nutrients). Once the system has been in place, the cost will be reduced to only nutrients and electricity (to keep the water system running, and lightning).

19. Long Return Per Investment

If you follow news on agriculture start-up, you may have known that there have been some new indoor hydroponic business started recently. That's a good thing for the agriculture sector and the development of Hydroponics as well. However, commercial growers still face some big challenges when starting with Hydroponics on a large scale. This is largely because of the high initial expenses and the long, uncertain ROI (return on investment). It's not easy to detail a clear profitable plan to urge for investment while there are also many other attractive high-tech fields out there that seem fairly promising for funding.

20. Diseases & Pests May Spread Quickly

You are growing plants in a closed system using water. In the case of plant infections or pests, they can escalate fast to plants on the same nutrient reservoir. In most cases, diseases and pests are not so much of problem in a small system of home growers.

So don't care much about these issues if you are beginners.

It's only complicated for big hydroponic greenhouses. So better to have a good disease management plan beforehand. For example, use just clean disease-free water sources and growing materials; checking the systems periodically.

                                                    ------THANK YOU------