Bio-organic Planting | Grow-bed & Pump | [ Part- 3 ]

This is the third part of the Bio-organic Planting series. If you want to read the second part please click here.


The medium that we grow our plants in is our next area of concern. Since the system constantly floods and flushes itself the space between the medium should be substantially high and it should let the water pass through easily.

 The ideal choice would be clay pebbles as they help maintain a minimum safe level of moisture and is easy to maintain. One can also used broken pieces of clay pots, small pebbles  or stones. The general idea is to avoid mud or sand or any medium that might clog the system or flow out through the siphon and into the fish tank.What I used for my prototype is a layer of broken clay tiles and then a very thin layer of granite stones over it. The clay tile pieces help maintain the moisture at lower levels.

 Another important point is the level up to which one should fill the medium. This depends on how we set the siphon. When the medium is flooded the water level should remain 1 to 2 cm below the surface of the medium, this is to prevent the formation of algae or other such matter over the growth medium. The ideal height of the growth medium fill is 30cm. This is required for proper root formation and stability of the plants.

The pump is a crucial part of the whole system, much like our heart. If the pump stops the whole system fails and both the plants and the fishes die. Fishes die of ammonia build up in the water and lack of oxygen and the plants die of dry roots. So when we select the pump we should keep in mind that it should be capable of running 24x7 all 365 days. Well, we sometimes use timers to control some large output pumps but generally they work all the time. So the general aspects on deciding the pump would be:

• How much water is to be pumped and circulated?
• What is the time interval to be maintained?
• How much power consumption are we looking at?
• What is the head/height of delivery?
• What is the available power source ?

 Larger areas require larger pumps. If a small pump is used in larger areas water takes a long time to fill and this can cause root rot, so we use higher output pumps. Some systems incorporate timers or sensors to control the pumps. Timers switch the pumps on and off as per the predefined time schedule. Generally the frequency increases surrounding the mid day as the temperature is higher and the frequency is drastically reduced at night. In a sensor based system the pump switches off when the water floods the medium and switches on again at the minimum level. The sensor based system however is not very common. Power consumption is another area of concern.

This is directly proportional to the area that we plant or the crop/fish output. So smaller the area the smaller should be the power consumption. Low power pumps do not have a large head, i.e  they can not pump high, so the growth medium should be kept as close to the tank as possible [above the tank]. The pumps can either be AC or DC powered. If you use power from solar panels a DC powered pump would be ideal. Inlet side of the pump will have a suction relative to the power of the pump and most pumps come with an inlet filter. The filter prevents the intake of large particles or small fish into the impeller of the pump. Ensure that the filter is kept clean as this affects the output and the life of the pump. For the prototype  I used a small 6.6Watt AC pump. The unit has been set up at a head of approx 30 cm from the bottom of the pump to the top of the output. I have incorporated a system that is similar to sprinkler/drip irrigation to maintain surface moisture.

In the next concluding part we will look at adding the fish and planting and aftercare.

Index:


Bio-organic Planting [ Part-1 ]

Bio-organic Planting | Building the Siphon | [ Part- 2 ]

Bio-organic Planting | Grow-bed & Pump | [ Part- 3 ]

Bio-organic Planting | Building the Siphon | [ Part- 2 ]

This is the second part of the Bio-organic Planting series. If you want to read the first part please click here.

So we move on to building the siphon.The big question would be "Why do we need a siphon in the first place?" The plant roots can decay if it is completely submerged in water for prolonged periods. There is also a need to aerate the roots for healthy plant growth. A constant cycle of flooding and emptying the plant growth medium is the best way to go. If we keep a simple drain at the bottom of the planting container the flooding wont happen and  if the drain is kept at the top, it would cause continuous flooding. So both these options are not feasible. The solution is therefore to use a siphon.

The siphon that is best suited for this purpose is the 'bell siphon'. It does three things :- starts the flushing of water from the growth medium at the required flooding level, maintains the flow even as water level drops and can also cut the flow at the specific required level to  maintain a minimum safe level of water.

 The bell siphon consists of three main parts. The inner pipe, the larger outer pipe sealed at the top and a water level sensing tube. Here is how it works:

• Water fills the tank and reaches the level of the inner pipe and starts flowing down the pipe.
• This starts a flow and creates a suction that continues because of the larger outer pipe maintaining a vacuum inside.
• As the water level reaches the lower tip of the level sensor tube, it sucks in air and breaks the vacuum thus stopping the flow and the next cycle begins.

 Below are a few snaps of a simple bell siphon I made out of left over pieces of pipe. I have sealed off the top part of the outer tube with a piece of acrylic which was cut in a circle. Ideally you can use an end cap to seal off the end.
Click the button below to view the steps involved:

The pump that I used in the project was a low output fish tank pump, to fill the growth medium container. So I used an inner tube smaller than the pumps inlet tube. If this is not done the siphon wont work properly for low output pumps. If you have a high discharge/output pump the recommended inner tube diameter is twice that of the inlet diameter. Test the system with the siphon in place before adding the growth medium and fine-tune it if required.

In the next part we will take a look at the growth medium and setting up the pump.




Index:


Bio-organic Planting [ Part-1 ]

Bio-organic Planting | Building the Siphon | [ Part- 2 ]

Bio-organic Planting | Grow-bed & Pump | [ Part- 3 ]

Bio-organic Planting [ Part-1 ]

I am currently working on an eco friendly looped cycle method of growing plants without chemical fertilizer or soil. So thought  I would  start a log on it as I go along. The word 'Bio-Organic Planting' is just a word that I came up with since I need to call this project something.Here are a few simple methods which we will combine later on in our project.


Aquaculture, also known as aqua-farming, is the farming of aquatic organisms such as fish.

Hydroponics is a method of growing plants using mineral nutrient solutions, in water, without soil. The medium is often ceramic pebbles , husk , broken tiles or any neutral medium that can support root formation. The nutrient rich water is circulated through this medium. 

Aeroponics , this process grows plants with no soil and extremely little water. Here we do not use any medium. There are misting/fogging chambers in which the plant roots get the required  growth nutrients.

Fishes discharge ammonia  through their gills and also through their waste matter. Ammonia build up in the water is unhealthy for fishes. Plants grow well in a nitrate rich environment. So if we have a method to convert the ammonia into nitrate we can use it for the plants. Hydroponic and aeroponic systems use nutrient rich water for plant growth. We can complete the cycle with the help of two good bacteria namely the 'Nitrosomonas' and the Nitrobacter'. 'Nitrosomonas' is a bacteria responsible for changing the ammonia to nitritre and 'Nitrobacter' is another bacteria responsible for changing this nitrite to nitrate.

To cut things short, we need the bacteria medium to convert the ammonia to nitrate and then to nitrate and finally we feed it to the plants. There are different methods to achieve this, but before that a few key points.... 

• Prolonged exposure of the plant roots to a submerged condition will lead to the roots getting rotten.
• The roots take in air and so it is healthy to aerate them on a timely basis for optimum growth.
• Since soil is not required we can use mediums like clay pebbles, broken bits of pots/clay-tiles or small stones. I have used a layer of broken tiles and then rock stones over it.
• The growth medium will provide an environment congenial for the bacteria to grow and facilitate the conversion of ammonia to nitrite and then to nitrate.
• The nitrate in the medium will then be absorbed by the plant roots and the clean water is send back to the fish farm.

So here is what we would need for a very basic proof of concept setup and the same is salable:

• A siphon system to control the filling and emptying cycle in the growth medium.
• Pump to pump up the water.
• Container to hold the growing medium.
• A reservoir to hold the fish.
• Tubing and plumbing

The Siphon:

We know that the prolonged exposure of roots to water can destroy the root structure or retard growth. So the ideal way is to create a continuous cycle of wetting the roots and then aerating it without making it extremely dry. So ideally we should flood the growth medium and then flush out the water and continuously repeat the process. This is possible by designing a siphon system in the growth medium.   

In part 2 we will start off by building the siphon. 




Index:


Bio-organic Planting [ Part-1 ]

Bio-organic Planting | Building the Siphon | [ Part- 2 ]

Bio-organic Planting | Grow-bed & Pump | [ Part- 3 ]