Good evening everybody, how are you all doing today?
It was quite an active day today.
We were building a pilot hydroponic growing system that will eventually be set up in a greenhouse, to see its benefits compared to some other water based growing techniques.
The name of the system is "RDWC" - or "Recirculating Deep Water Culture".
So what the smoke is RDWC?!
Well the easy answer (annoying?) is that RDWC is like DWC but recirculating ;)
But for those of you that are not familiar with all this terminology, please allow me to clarify.
So in order to understand what is the recirculating part of the system stands for, we first need to understand the "deep water culture" part.
I am not going to dive here into what is hydroponics in general, and how it is different from growing in soil...the basic idea of hydroponic growing is the fact that we provide the food to the plants via fertilizer enriched water, rather than basing it nutritional needs on various biological processes that naturally occur in soil.
There is a plethora of variations for hydroponic growing techniques, starting from basic drip based systems like the "dutch buckets", to commonly used NFT systems, Dwc, aeroponic and many more.
The main difference between all those techniques is in the way that nutritious water is actually delivered to the root mass.
So in NFT (nutrient film technique) for example, the plants are grown in horizontally positioned gullies, while the tips of the roots are directly submerged in a thin layer (film) of nutrition enriched water.
They can also be stacked:
Or even spiraled ;)
On the other hand, In aeroponic systems, the nutritious water is misted or sprayed on the roots, providing a well oxygenated, and readily available food for those precious plants.
But today we are talking about the Deep Water Culture technique, or actually its upgraded variation, the RDWC.
So as the name suggests in this technique the plants roots are actually submerged in deep nutritious water.
*image credit:Royal Queen Seeds
You cannot simply submerge plants in water (be it with or without fertilizer) and expect them to thrive.
Roots need plenty of oxygen in the water in order to properly absorb those nutrients and for numerous other essential plant functions.
In other systems like NFT only the tips of the roots are submerged in water, leaving most of it exposed to the air, providing the roots plenty of oxygen to thrive, but in DWC usually the root mass is deeply submerged in water, living it not air to extract its oxygen from.
So the oxygen is provided externally via some kind of air pump.
So the idea is simple, take some kind of a container (it can be as simple as a food container (non transparent), make a few holes to sit a net cup of a sort, add an air pump and an airstone, put some fertilizer and plant your plants.
And frankly it works great on small scales as all you need to do is monitor only one water tank, being the actual growing tank.
So if you notice that the fertilizer levels are dropping you can easily add some more, and if the PH range is drifting away from the optimal, you simply adjust it accordingly by adding the relevant substance straight to your growing container.
And if you need to change your water after a week or so, when using a weekly scheduled nutritions, you simply pour out the water to your vegetable garden and prepare a new solution.
The problem starts when you start adding those containers…
Even if you premix your nutrition in a separate reservoir and then fill up the actual growing containers, after several days and sometimes even hours, the balance of the water will be different in each and every one of those containers, making them grow and produce unuiformly.
The fertilizer concentration and ph levels will be affected by numerous reasons and will require you to monitor each one of those growing containers individually.
That might have benefit for some growers, that plan to plant different types of plants or plants in different growth stages in those containers...
But this is of course not the best idea if you are going to put plant of the same type and growing stage and want to minimize the amount of time you spend on the maintenance of your setup.
And it's even worse idea if you plan to use some kind of controller to auto dose the nutrients and the acids into the water (as we plan to do in the current installation).
So this is where the "recirculating" part comes in.
So the goal is simple - and it's to be able to exchange and mix between the water in all of the growing containers and the main reservoir, and by allowing us to monitor and adjust the water in only one place and have it exchanged with the rest of the water in the system.
We achieve this by setting up a water pump in addition to the air pump that usually used in DWC systems.
The job of the pump is to move water from one part of the system back to the reservoir and by that recirculate all the water in the system, making it properly balance between all the growing containers.
There are 2 ways to do that (they can even be called sub-techniques of the RDWC technique), and they are called "Undercurrent RDWC" and "Overflow RDWC" (there are some other names but we are not writing a dictionary here, aren't we).
Both of the techniques are based on recirculating the solution in the growing pods by pumping water from one place to another within the system.
It is achieved by interconnecting all the buckets with a pipe, by making holes in the bottom of the container and putting some kind of a gasket to allow the pipe to come through without any leaks.
The difference between the Undercurrent technique to Overflow, is in the way that water is transferred.
Without going to much into technicalities here, the overflow system usually has the water pump submerged in the main reservoir pumping water through the main feed line to all of the containers, and through means of hydraulic pressure this water is mixed throughout the system via the bottom drain pipes, interconnecting all the buckets.
The Undercurrent technique on the other hand has the pump sitting outside of the reservoir, and instead of pumping the water from the reservoir to the system, it rather pulls the water from the system back to the reservoir.
The principle is the same, just the implementation is slightly different.
There are many debates on which one of the techniques is better, but in my opinion, as long as you do it properly, making sure the hydraulic pressure is balanced and you have proper flow and water exchange through the system, then it doesn't really matter which one you choose.
In this case we have decided to go for the undercurrent setup, as it allows slightly better control with regards to drainage.
So the current setup will be initially consisted of about 20 , 18 litre buckets.
They will have a main reservoir consisting of 2 sixty litre tanks, 3000 L/H water pump, 60 L/M air compressor and a bunch of accessories like 5" net cups, clay pebbles, air stones etc…
The buckets will be interconnected with a 2" (50mm) pipe, right in the bottom of the bucket, and a ¾" (20mm) main feed line.
The hole system will be connected to a water chiller that will be constantly monitoring and adjusting the water temperature and a dosing controller, that will be monitoring and adjusting the nutrition and the PH levels of the water.
The controller will also have an electric solenoid valve that will automatically top water as needed.
The tubing is set up in that way the flow of the pump can be switched (via flow controllers) to allow easy draining and refill of the whole system.
Every bucket will get its own airstone to supply as much oxygen as possible to the root zone.
I was using those golf-shaped airstones, but decided to switch to those disc shaped ones as they provide much butter air distribution.
The plants will be planted in the 5" net cups and with time their roots should grow right trough those cups, straight into the the oxygynated water.
There is still a long way to go with assemblying the whole thing, just to make sure it works properly and that we dont have some surprising leaks.
But thats for tomorrow...or maybe next week...
Time to have my 4:20 (16:20) moment and do my daily trading, Bitcoin is going a bit crazy today...
I was smoking some nice sativa today. To be honest, i am not sure which strain it is, but it was doing the work no doubt!
Strangly, the only thing around that can be used as a rolling tray is a solar panel..maybe my nuggets will get some vitamin D ;).
Now a quick update on my witness...
I gotta admit it was a rough start...after sharing with you in my previous post about succesfully running my witness, I woke up the next day, to see that it was actually down.
I guess I was happy to early...
Of course after noticing that it was down (the strange part is that the sessions were still running) I immidiatly relunched it, just to have it go offline again after couple hours...
This saga continued througout the day and every couple hours my witness kept showing offline.
But after doing some tests, changing some keys and finally rebooting the whole thing, Mr' Ubuntu decided to finaly start witnessing...
Its been 3 days now and no issues...so I guess I can call it a win, my witness is officaily up and running!
So if you still haven't done so, i will appreciate if you can head over to the witness page and throw me a vote, with the number of currently active witnesses you probably have a few unused votes so you might as well use them on an active witness :)
I want to thanl @herbncrypto once more, for being awesomly patient with me and helping me out to resolve the issue with myu witness setup.
Dude you are awesome! Please except my humble token of gratitude...
See ya all next time, untill then I wish you all the best.
If you Liked my post and feeling generous, Crypto-Tips are always welcome :) (wink wink)
MY BTC Wallet : 1aAFg9RUqda8sYnhLfHgnc4cep7c3kFSo
MY ETH Wallet : 0x2DEB7dDB01Ae0f269278A4CdaE0B650d9f7BA5AC