New member with Unusual system

[Aroidgrower]

Well I think I should first introduce myself. My name is Brian William's I own and operate a retail and online nursery. I live and operate out of Louisville KY and I grow mainly rare and unusual tropical plants.
Last season I had decided to look into hydroponics and aquaponics for growing my plants. I was have trouble with employees not watering enough and many of the plants I grow can grow as partial aquatics. Which I had figured should make them easy to work with in a hydroponics type system. Here is a general idea of the plants I am growing in this system Colocasias, Alocasias, Bananas, Philodendrons, and many more. I had some problems right from the start with finding information for a system I would need. Most of the other systems I have seen were not on a larger scale or were not dealing with the situations I faced. I needed something that could produce nice healthy plants in pots with a cheep cost to build. I had tables already in place from years past and they slanted down hill. So I drew up a few ideas of what I thought my system should do and how it should work.
The first table is 4 feet wide and a little over 100 feet long. I lined the table with pond liner and placed capillary matting over the top. This was to prevent any dry areas. At the end of the table was a large container to catch the runoff water and to recycle it back to the top of the table.
The system worked extremely well in the spring and first of the summer. I could tell by mid to late summer that some plants were not growing as well. A inspection of the roots showed that the root systems and root tips were rotting. I have a few theories as to why this maybe happening. One was over fertilizing in the water. Many of the plants were not repotted for this set up and the time release fertilizers may have been leaching out into the systems water. Another idea was lack of oxygen in the water this is something I am still working on to fix. Also with the lack of oxygen I have been looking for the best mix to use in the pots and trays. Some experiments at the end of season showed that a mix of perlite and clay sand used at the bottom of the pots with a neutral grow mix on top worked well. My plants are shipped by mail order and I need them to be able to handle a trip out of the system for a considerable amount of time. I have been trying to use a mix that holds some water as well as can handle the system. This maybe one of the most different parts of my system as I have been trying to grow in media and soiless mixes. Finding the right mix that is cost friendly I am sure will be a key to getting better results.
The last problem I discovered was the tank was not in the ground and that the water was getting very warm in the summer. I have thought about getting a larger tank and putting it in the ground. One table has a small tank which I am not sure if I can move but maybe able to add another tank to.

One question I am trying to figure out at the moment with my system is if I should have a small constant drip running down the table or if I should have a fast flowing steady flow? I am not sure which would work best and have found little info on either. I guess some experimentation could be done but this is tough to do in the growing season.

I am posting photos of the system when I first put it together. I am looking for good ideas and any info on similar systems. At the moment the system is on a constant flow. I have read very little on constant flow systems. Their maybe some design flaws or something I am over looking that could make this work much better. I am here to learn so feel free to give me any suggestions.
I built a few other systems after these and will post more soon. Thanks.

[Aroidgrower]

Photos of my other table. This table is built in a U shape one table pours into another and then onto another back to were it started. The pump then only has to push the water a few feet away. I had similar luck with this system working great in spring and rot problems by end of summer. Hopefully I can figure out my problem and correct it. The results in the spring, were so good I am sure I am close to getting it to work all season great if tweaked a bit more. The following photos are of the tables being constructed.

Last but not least are some photos of one of the tables running. This was in the spring when the table was preforming great

[Murray]

Hi Aroidgrower,
It is indeed an unusual system. It is right outside accepted practice for both aquaponics and hydroponics so I suppose you are right in experimental mode.
What process did you go through to get the system you have built or partly built ? Did you get some info from somewhere to take you down the flat shallow tray road ? Perhaps there may be more info form that source that can extend your knowledge.
The rotting roots are lack of oxygen in simple terms, as water temp rises there is less dissolved oxygen in a given body of water, so in summer time the water temp would have risen especially as the water travells along the flat trays.

In NFT systems there is a very thin fast stream of water over short distances.
I would think on just an initial look at your photos the run for the water is too long, nutrients and dissolved oxygen will be expended by the time the water gets to the other end.

Others may be able to assist with further info.

[Aroidgrower]

The idea for the system was all my own. I probably should have done a bit more research before jumping in but for what I already had and what I needed the system to do. I am not sure I could done many things different. I believe a NFT system is possibly the closest I have found to what I have. I did some research on a very slow drip system were the table stays moist and not really wet at all times. I am not sure if this system is still considered a hydroponics type system or just a high end capillary system. All I am looking for is performance in the plants. I am considering testing this out before moving further. As for adding nutrients in the long table I have decided to add sections in the main water line that will spray out every 10 to 15 feet. This should add more oxygen to the water and get The nutrients to the plants.
I am still not sure how to adjust the U shaped table. I plan to add more oxygen the catch tank at the end has been put in the ground already and I plan to put a lip at the end to produce a type of waterfall effect. I also have two other sections of the table that step down a 4 inches or so to also cause this waterfall effect. I have been thinking of adding a new tank to the front of this table for more fish.
I am not sure at times if this is a true hydroponics or aquaponic system due to the fact that I have not figured out yet what growing media works best. Many of the plants grew well in a 10% peat 40% perlite 50% expanded clay sand.

The idea for my system came mostly form my last visit to Agri starts Tissue culture nursery. They have a multimillion dollar hydroponics greenhouse that uses a flood and drain system. I was attempting to duplicate the process with a small budget. Many of the plants that was in the system can commonly grow in ponds. I had figured they would do well in this system but the lack of oxygen was something I did not foresee.

[GaryD]

Hi,

You might like to take a look at the Smart Valve as a means of controlling the flow of nutrients to your plants.

The valve can be mounted in a shallow tray (in which you'd sit the pots)and will only allow more water to flow to the pots once they have used the previous lot of water.

This system is very precise in terms of water and nutrient use....and it doesn't recirculate so disease potential is also reduced. Your root problems would also probably cease if the plant roots weren't constantly in water.

Anyway, check it out at http://www.autopot.com.au/

Gary

[DaveOponic]

I'm surprised that the tables aren't covered in green algae. What material have you used on the trays? Have you had algae problems? Even in my NFT system around the pipes where there is sunlight, green algae forms.