Organizing Your Channels

Arranging your channels can make a big difference to system design. This is an example of arranging the channels in parallel. At first that seems like a great idea, very geometric and regular. What it does mean is that you can minimize the support structure, here it is just two U-shaped sections of thin walled conduit. There are two down sides in my experience:

1. You can't get to the inside channels easily and as the plants grow it becomes a jungle. But even at the beginning it is impossible to reach the inner channels to manipulate the support strings or maintain the system.
   
2. You have to build a nutrient return to the tank.

So this is an example of a channel organization that seems quite natural but doesn't work out all that well.

How does that work again?

In a NFT (Nutrient Film Technique) system the plants are put in a channel (usually flat bottomed for a purist) and nutrient is pumped to the end of the channel and flows by gravity back to the tank. In the detail at the right you see the way I mount my channels. There is a 3/4" thin walled conduit pounded into the ground for primary support and then a piece of 1/2" conduit is dropped in on which a little pedestal is mounted which has a carriage bolt through it. A 3" hold is drilled in the channel where the plant is mounted. A parallel PVC tube carries the nutrient to the end of the channel where it is fed in with a 1/4" tube into a drilled 6mm hole. Works well!

Support System

When you grow plants like tomatoes or cucumbers or even peppers you need to support them. This requires a support structure of some kind. When I was first starting out I used an A-Frame but that really doesn't work too well because it draws the top of the plants together. You get enough of a jungle as it is, but if you force the plants together then you get such a tangle that finding the fruit can be an adventure.
So what's the solution? Well you'd like something that goes straight up, but it has to be able to handle a fair amount of weight. I've never actually estimated it, but it might end up being almost a hundred pounds, certainly over fifty per channel.
The solution that I finally came up with was thin-walled conduit. I drop 3/4 inch conduit into 1" conduit supports and then run cross beams of 3/4" conduit by joining it with 90 degree 1" conduit bends. Then I cross brace with 1/2" conduit held in place by wrapping it with those small bungie cords. The picture at right shows what my overhead structure looks like on a fairly large NFT system in the backyard.

Measuring Nutrient Strength

You won't be doing hydroponics too long before you discover that you can't do it very well if you don't know how strong your nutrient solution is. The plants need to be fed consistently at an optimum strength and the usual way to control this is with a conductivity meter. (See the picture at right of the Dipstick which is about $85 and a slightly more recent version of the first instrument I got for doing hydroponics).
When nutrients (non-organic salts) are dissolved in water they disassociate into ions and make the water slightly conductive. Using a meter you can tell how much dissolved nutrient is in solution. Unfortunately you can't tell the composition, i.e. how much of different nutrients make up the solution. So ever few weeks it is a good idea to dump the nutrient and remix to reestablish a known nutrient composition. This can be done when the tank has gone down a good bit so that relatively little nutrient is lost.
If you want to see a selection of meters you can CLICK HERE and it will take you to a Portland Oregon firm, American Agriculture. This is just an example of what is out there.

Simple Systems

Among the simplest kind of systems you can build is the float system. Here's a picture of an easy one. You probably recognize a couple of those plastic organizing tubs you can get for a few bucks at the store. The particular system uses styrofoam to literally "float" the system. Holes cut in the styrofoam are filled with little cups with the plants in them and nutrient is mixed into the water.

The system is aerated by a small aquarium pump to make sure there is oxygen in the nutrient. The system in front has some garden lettuce in it and the system in back has Romaine. It grows like gangbusters and you never have to water or weed. You do have to check the water level and nutrient concentration every couple of days. That takes about two minutes.

Starting Plants

Getting plants started is pretty much the same as with ordinary gardening except that you generally want to start them in a passive, non-organically based medium. The main reason for that is to make sure you don't get either disease organisms or a medium that will distribute particulates into your nutrient solution where, if you're using NFT or other methods that require pumps, the particulates can interfere with the pumps.
The picture here is of a cucumber plant started in a perlite cup and embedded into a hole cut in a 4" diameter 10' long PVC channel which nutrient flows down. To prepare the cup I generally put a little loose rockwool in the bottom of the cup after cutting triangular cuts in the bottom sides of the cup which I fold out. The rockwool fills the cup to over the height of the triangular cuts so that the perlite that I put on top doesn't have a chance to flow out into the nutrient solution. The use of the perlite ensures that there is a portion of the root zone that is easily accessible to oxygen and keeps the cucumber roots from being too flooded over their whole length. My experience is that the cucumbers like this a bit better than just being rooted in rockwool cubes.
I position the cup in the channel so that the holes lie directly in the line of nutrient flow. When the roots get down to the holes they exit into the nutrient flow directly so the plant always has lots of nutrition. That's really all there is to it though. It's pretty simple.

Keeping Notes

Whatever you do when you're dreaming about doing your own Hydroponics Garden and having your own personal adventure, you want to keep notes. Nothing succeeds like a well thought out strategy. I always keep a quadrille notebook and sketch out my ideas for systems. It's great fun, especially on some of those lazy Winter days when you don't want to go out because it's too cold.

As May rolls around you don't have much time. Here's a page from my notebook back in 2002 when I put out all sorts of systems. There was a 4 tube 2/3rds Star System, an NFT lettuce system and a table full of tub float systems.

As I was dreaming up the systems I'd draw these diagrams and make notes of what I might need. Then it was off to the design center (Lowes, Home Depot, Walmart, ... wherever there are plastic bric-a-brac from which to cobble up a system. Each and every design is an adventure.