Backyard Aquaponics
A place to discuss aquaponics

I keep reading that grow beds should be 12 inches deep. Why?

Why cant the bacteria grow just as well in a 6 inch pipe full of gravel or what ever?

It would be so much simpler to make grow beds 50 feet long and stack them 4 feet tall to use vertical space using 6 inch pvc.

Bacteria grows everywhere, of course, but the stuff we want prefers darker conditions. 12" has been found to be optimal to get good volume in a given footprint, and to provide dark conditions. It's not a magic number or anything.

Do keep in mind that if you fill 6" PVC with gravel, and then put plants in, you may have difficulty removing root mass. King Eric recently had problems where the roots grew so well that it clogged the pipe and caused overflowing water. (Think it was him.) In fact, you might want to review his system. He has a long narrow space along a fence, and did something similar to what you may be thinking. Also, I think it is Jay's system where he has vertical pipes with little pockets for the plants. That is a small system, but nicely designed.

So if it is darkness the bacteria needs why can I not spray the pipe with crome paint made for plastic?

I have grown tomatoes in pipe before. It just requires a smaller pipe in the bottom to allow the water to flow in bypass mode if the pipe were to stop up. I understand the risk.

Can you tell I would really like to add a pipe grow bed? lol

I can not find anything other than barrels for a grow bed. I can get 6 inch pvc pipe for the same price per foot as used $8/drum plastic barrels. Further, the only food grad barrels I can find are 30 gallon. That the reason I asked. I am a little hesitant to use chemical barrels; not even knowing what was in them.

I think another reason for the 12" depth is to provide support for the plants, although all my plants have had small root balls (I guess because they can too easily get to nutrients they need) so they need to be supported by other means anyway.

Dan,

Your hydroponic Growbeds were/are perfect! I think the deeper base also tends to help with stability of the larger plants. Why not just have more of the same Growbeds you already have? and put some pipe in there as well. Several people on the forum have multiple methods in their systems. Jaymie for instance has several, large system, Janet has some floating (duckweed) as well as a regular GB -smaller system. So there are lots of ways to mix it up. The 12" also seems to give a hugh "bio filter" while taking up very little extra space compared to the area you are growing the plants in.

Rup mentioned something about not carrying over the hydro ponic thoughts, I had studied the aquaculture and the hydroponic and therefore was convinced that you had to have bio filters and remove solids, etc. etc. However, once I sat down and thought about this meathod that the Speraneo's and Joel and most of the rest of the folks here are using, it made total sense and made things much simpler. Just grow your plants in your bio filter so to speak.

Your Hydro set up is perfect, just take out the fertilizer, make your sump Much bigger, and fill it with fish. The plant side of it is alreay done.

You should post the pics of your hydro beds, if you don't tell anyone on here, they would all think you have a successfull AP sys.

Just a few thoughts.

The wood frames are not going to last very long. I was hoping to use something that would have a longer life. My grow beds are 8 inches deep and do fine holding a 4 foot sun flower up.

The load time is HUGE (*dial up customers skip this one). Here is a my hydroponic beds. I have not fixed the spelling so just ignore it. I just threw this up on the web in 5 minuets before leaving so I could show someone my growth rate. Each of theses beds give about 4 pounds of vegies every day. My tank is in the ground.. I could put fish in there.... Hmmm... That would keep them from freezing.. Its a 200 gallon tank with 398 gallons of grow bed; 80 square feet of growing surface. It has a 1/2 HP 900 GMP waste water pump in it. That might suck up the fish and feed them to the plants.. I would also have to change the drain type to auto siphon so algae and junk would not stop up the weep holes.

Na, I'm not so sure. I will try to find something to make grow beds out of..

Here I sized three pics down:

Very nice dan couple questions whats the allfoil on the pipes [cooling] And i see you visiting late at night [ute headlights on ] you are not growing any think else there are you do you have a moonshine still hidden there to

The foil is to block sun light from the inside of the pipes. It prevents algae buildup. in the pipes and tank.. You know a clean system.. I had 4 O'clocks, sun flowers and elm trees come up in my beds even after washing the gravel.

With fish that would not be a problem. They would eat it.

And I dont do moon shine, just wine

Thanks for that will be interesting to see how the aqua comes up against the hydro jim here in aus is doing a test also .I also have a section that just buy turning off 2 taps i can run hydro .Theres a person in perth with a large hydro setup he is running fish in some tanks for mozzie controll

Great analogy Mathew!

I updated the page with hydroponic system on it to include two trial system pictures.

I think dwc might very well be an option for fish. I also think it would be best to do aquaponics on this current system to compare. There are already air stones in the tank. The only problem is how am I going to get the fish out of the tank.... If they all hide on one side at the bottom there is no way I can reach them. Also, I really dont know if they will get sucked into the pump.. Removing the pump is not something I really want to do; and I cant reach it. I would have to cut the 1.5 inch pipe then splice it back together. <gripe gripe>

Would the tilapia survive the winter in the tank? There is no way to insulate it. Water coming from the grow beds is bound to be cold.

make a net with a frame the shape of the tank, lower it to the bottom and raise it up whenever you want fish. You could even put in some form of extention on it so it will not lower all the way down, effectively makeing a false bottom, which would protect your pump/fish from each other.

Just picture the turkey oil fryer, the same way you pull that turkey up out of the oil, pull the fish up out of the water.

And by doing so increase surface area for Bio, I like it!

Amen to that Dandee.... very nice setup and if Matthew hadn't said anything then it could have easily passed as an AP system....

The only thing the seems to be preventing it be converted straight over is access to the fish....

as Matthew says .... just plant straight into the bio-filter, the growbeds...

You already have the basics of flood and drain down pat... the rest is just fine tuning...



Because AP systems are recirculating by nature and fish are highly suseptible to chemicals and metal poisoning.....

The constant exposure of your fish to levels of any metal (chrome etc) would result in accumulated levels in the flesh of your fish over time.

Plants only take up elements and minerals in there ionic form (salts to hydro growers) and immediately convert them into inert plant structures.

Therefore they don't accumulate toxic substance like fish and other animals do.

Secondly, most hydroponics, although utilising chemicals that in themselves could be possibly harmful, usually are "run to waste" and dumped after a short period...

Obviously in a recirculating system this isn't the case.

Make sense Dandee?