Backyard Aquaponics
A place to discuss aquaponics

Hi All,

Just to preface I'm a complete newbie to hydroponics and have been watching alot of YouTube videos and reading up on different designs (which I think has worked a bit against me as I'm confused about which design to use).

My current plan is to build a first time small system outside using 4 inch PVC that runs horizontally and mounted vertically to suit a small unused space.

The system I believe I'm looking at is NFT or similar to. There are two different designs I've seen with this style (round PVC pipes mounted vertically) and that is:

1. 90 degree bends are at the end of a run that connects to the pipe below it, as a result the water level is low and there is a small stream of water in the bottom of the pipe. If a power failure was to occur water would drain from the pipes back into the reservoir.

2. The end of each runs are capped off to create a dam effect and an outlet is placed at a certain height to maintain a higher water level before water is passed to the next row of piping. Water level is alot higher.

I'm having trouble deciding on which design to go with, I see the benefit with having a "dam" style to maintain a water level if power was to fail. However with the higher water height would you need to be more careful with roots being completely inundated with water? I'm trying to understand the pros and cons of both.

I don't have any huge plans on exactly what I want to grow, primarily to start I was thinking cos lettuce, lemongrass, mint and kale.

Any help would be greatly appreciated.

Root inundated with water is not usually a problem for most hydroponically grown plants provided there is enough desolved oxygen in the water. Here is mint and spring onion constantly submerged in water in a concrete stock trough in my system. Both grown kitchen scraps.

Most plants will grow fine in constant flood... even earthworms enjoy it, but the dams will eventually fill with silt if you are not drawing water from a sump that contains only water that has been through a grow bed. ie filtered crystal clear water.

Roots will also collect silt, but that's not such a big deal if you are eating the plants with the roots. If it's lettuce or something you are pulling out, that won't be a problem, but if you are growing something you intend to let sit there for a few years you might get some silt blockage.

I had some issues with strawberry plants after year two, but I was pulling water directly from my fish tank, so there were some big solids.

But none of that matters if you have space (ie enough depth) for the water to flow past any buildup of silt.

Also if you are growing anything bigger than lettuce I'd recommend 6" PVC versus 4" since it will try to clog with roots.