Hydroponics

Hydroponics came from the Greek words “Hydro” meaning water and then “ponos” meaning labour, the name for this word “working water” was coined by Dr William F. Gericke in 1920’s, although the actual name was created in the 1920’s, that act of using nutrients and water to grow plants started much earlier in time by the Babylonians in the 6th Century. The arid desert meant that they needed a way to irrigate their crops with little or no substrates there for using Hydroponics to grow their food.

Hydroponics is typically a way of Growing plants with little or no substrates by delivering water and nutrients to the root zone. This way of growing has many benefits such as:
Faster growth cycles
Reduced waste
Increased yields
More control

Hydroponics in Horticulture has been used all around the world since the Babylonians, the Aztecs, the Chinese, and many others have used this as a way of growing crops. Many of these people designed different ways of using Hydroponics that are still used today and an example of this comes from the floating gardens of China which was developed over 3000 years ago.

This is a very common method used today in developed and non-developed countries for growing, for example lettuce on both small to huge scales of horticulture, the tiny lettuce is simply placed into a float (this can be trays of polystyrene) the roots go directly into the water that are fed with nutrients and oxygen via pumps, the trays then float on the water, as new trays are placed in the water bed the older trays at the front are harvested.

This method of Horticulture has been used for over 300 years, they call this “Dhap” locally known as “Baira” these floating vegetable gardens are becoming much more popular and work well for the Bangladeshi’s as they simply rise and fall with the flood water which will inevitable only get worse with climate change.

There are various methods of hydroponics they include Drip irrigation, Wicking, Ebb and Flow, Nutrient film technique, water culture, Aeroponics and Flood and drain.

The first method is Drip Irrigation

This is basically when the water and nutrient are push from a central reservoir down pipes into small drippers that are pushed into the desired area. This works well as it minimizes water evaporation as the holding reservoir can be kept sealed and in a cool place, nutrient loss from leaching is reduced and the user has much greater control over feeding. The downside can be blockages where the drippers get clogged up, there is maintenance to keep the system working well, but this is to be expected with any system put in place and in an outdoor setting the irrigation tubes can get damaged over time.

Wicking Beds

This method of growing uses 80% less water than a typical raised bed and because of this the user will typically get less weed growth as the moisture isn’t there for them to establish, meaning bigger yields for the plants that the user wants to grow. The other advantage is that its hard to over water as the plants take the water they need as they want it. Also, the system requires no pumps meaning no need for electric and no noise. The disadvantage is that they do use more substrate than most other hydroponic systems and the grower has little control of how much nutrient they are administering and measuring run is hard as well.

Ebb and flow

Ebb and flow is a form of hydroponics that enables your roots to breath, the ebb and flow motion leaves the roots exposed to air a lot of the day as the water ebbs back into the reservoir oxygenating the water as it does so. Once the pumps turn on, the water floods the plants roots feeding them once again with nutrient and oxygen rich water.

The problem can arise if the pumps don’t come on, the user must also keep the water at the correct temperature and ensure that the P.H and E.C levels are kept within the right parameters. This will mean a change of water at least every 7 days.

Nutrient film Technique

This method of growing uses very little substrate, most users start their plants off in either peat, coir pellets or rockwool cubes. For this method of growing, rockwool cubes are much cleaner and transfer well into the larger rockwool cubes which are usually three or four inch in diameter although larger six-inch cubes are available.

The Rockwool blocks are placed on a spreader mat that has been laid on a bed, this is usually made from plastic and usually has ridges moulded into it that allow the water to run under the roots that grow into the spreader matt.

The idea is that the water is pushed by the pump from the reservoir via a tube onto the bed that water runs along. The bed is set at a slight angle, feeding all the plants allowing the water to flow down towards the reservoir. The pump is constantly on recirculating the nutrient rich water. Oxygen is created as the liquid falls from the tray back into the reservoir.

This method allows the plants to grow quickly as there is an abundance of air to water ratio and there is very little in way of substrate, the cost of nutrients is little as the system recirculates them for days before the user needs to replenish them.

The downside to this method is that it needs electric for the pumps, as the liquid is always being recirculated, the water needs constant management for PH, EC and temperature. Cleaning of the reservoir can be a pain as in some cases the tray sits directly over the reservoir, water change is advised every 7 days minimum.

Water Culture or DWC (Deep water culture)

Deep water culture allows the roots to grow directly into a nutrient rich water solution. The cuttings can be placed into trays and floated on water or in many examples (mainly for larger growing plants) each plant has its own pot, the plant is usually placed in a net pot within a larger plastic Tub, each Tub is linked together by tubes which allow the nutrient rich water to be pushed around the system. The roots then dangle from the net pot into the nutrient solution. There is a central tank which will house an air pump and recirculating pump, this is where the user will fill the system and make all the relevant checks for P.H, E.C and take water temperature readings.

The advantage to this system is that little or no substrate are needed, plants grown in this manner can easily up take nutrients along with the massively oxygenated water, the yields can be very big, and plants can be fast growing.

The disadvantages are that you need electric, it can be an expensive system to set up because of all the pumps and accessories needed, the user must keep an keen eye on the water for nutrient swings and oxygen levels.

Aeroponics

This method of growing is probably the most advanced method of growing plants hydroponically, the user will get faster growing, healthier plants with larger yields. Plants are usually grown in rockwool which is an inert substrate. There are different forms of aeroponics but usually the roots are sprayed or misted via sprinklers with a fine nutrient rich solution. This enables the roots to breath and uptake maximum nutrient and oxygen at the same time. The plants hang from basket or pots over sprinkler, the pump delivers the solution to the sprinklers or fogger that then mists the dangling roots. The water then can run to waste or recirculate.

The advantages are much bigger yields, less substrate, more control over your garden with less resources and it produces an amazing root system.

The disadvantage for larger growing plants is that the roots can block the sprinklers as they get so big, the roots if they grow so big can coil up and then get root rot. The system can be expensive to set up and the user needs to be quite technical minded to keep every running smoothly regarding PH.EC.

Flood and Drain

Flood and Drain is popular with growers wanting to grow larger plants. This method of growing usually starts with a large reservoir, enough nutrient solution is needed to flood the tubs in the system.

Each Tub is then connected to a central line that leads back to the main reservoir, a timer is then connected to a brain that tells the main pump in the reservoir when to feed and how long for. There is then another pump that retrieves the water and pumps it back into the main reservoir.

Each Tub connected to the main line has another pot inside it, this can be a net pot for those that want to grow with less substrate or another bigger pot that hugs more closely the outer tub. Usually, a copper disc is placed at the bottom of the pot which stops the roots coming out the bottom and blocking the feed lines.

The system can be added to as long as the reservoir is big enough to hold the water the extra tubs would need for the plants to be watered.

The advantage of the flood and drain system is that system pulls oxygen into the roots zone as it ebbs back into the reservoir, the nutrient solution also oxygenates itself as it flows back. Plants can easily be swapped out. The reservoir can be easily oxygenated by adding more air pumps. The system can be easily added to.

The disadvantages are that the system can be expensive to set up, electric is needed, and the pumps can be noisy, this is a recirculating system which mean that there can be swings in PH. The system needs cleaning out each week. Also, the roots can block the feed pipe.