Sunday, August 31, 2008

Looking at Roots

You don't need a whole lot to get started in hydroponics — just a plant and some nutrients and you can even experiment with your own mix of nutrients. It's helpful to have a conductivity meter to have some idea of how strong your nutrient mix is but once you have that you're pretty much good to go.

The picture here is of a system I used to grow tomatoes inside in my home office over one Winter. After a while they grew so large I decided that when the Spring came to retire the system and took it outdoors. Here I'm spreading the root mat that had developed over the several months the system was growing indoors. The system itself was just a simple wick system. A wick system just starts by putting rags or strings or anything that will "wick" nutrient up to the plant. It isn't long before the roots follow the moisture down into the nutrient solution and the wick itself become somewhat superfluous. The roots themselves form a fine webbing that draws nutrient up to the plant. It's quite a fascinating thing.

Saturday, August 23, 2008

Sometimes things don't go well ...

When I was first designing systems (design is probably an exaggeration) I just secured channels to sawhorses, two to a pair of sawhorses. The tricky thing was trying to figure out the support structure. Tomatoes need a lot of support. The first try was to make a little A-frame and run strings from it, but that made the tomatoes grow together and form a total rats-nest jungle.

So the solution was to build individual vertical supports, so I created a set of wooden frames but I made the frames with wood that was way too small. (I can hear my wife snickering — she's better at visualizing disaster than I am. She's never said "I told you so", just rolled her eyes a little.) With the help of my son Christopher we build some frames, but as the plants grew and grew the frames began to tilt and the horizontals overhead that the strings were tied to began to bow. We saw we had a problem so we tried to brace things with a rope. But then one fateful day, while I was adding nutrient to the tank I noticed the frames leaning over more and more and suddenly the tipping point was reached — Whoomph! Down they went. That sent me back to the school of more rigorous design.

Friday, August 22, 2008

Growing Indoors and Friends

Shortly after the first article I wrote about hydroponics appeared in The Growing Edge I got an email from Marlan Showalter. He described himself as an enthusiastic hydroponics hobbyist himself and said he had a store in the Dayton Farmer's Market, a regional attraction in Dayton Virginia where a host of small proprietors from the Mennonite community did business.

I just figured anyone in business would likley be middle-aged, so when I went down to meet Marlan I expected at least a 30 something to 40 something fellow. So you can imagine my surprise when Marlan turned out to be a personable young man of about 20. He was selling a variety of produce in his shop including hydroponically grown lettuce from a local hydroponics grower. To show people what hydroponics was all about he had a little system growing lettuce under flourescent lights. (see the photo) This is a miniature two channel system. The lights are just a tad anemic for growing lettuce but it will grow. Many plants that are able to grow in deep shade will grow just fine under flourescent lights, but from the viewpoint of what plants expect, they are not all that bright.

Thursday, August 21, 2008

You Can Grow Anything

One of the amazing things about hydroponics is that it is so open ended. You can grow almost anything, it's just a matter of getting it fine tuned a little and often that's not even much of a problem.

I've personally grown tomatoes, cucumbers, peppers, lettuce (several varieties), beans, herbs, strawberries, corn, egg plant, and squash. Some plants don't like to be grown with others because of different nutrient concentration preferences. For example lettuce runs at a lot lower nutrient concentration than tomatoes. But as long as you check it out you can generally grow it. I remember being astounded that you can even grow roots crops and I actually grew a rather stubby carrot one time and people grow potatoes.

If there is a way to grow it in dirt, there is likely a way to grow it hydroponically. That is simply great fun!

Tuesday, August 19, 2008

Starting plants

It's pretty easy to start plants. I always start from seeds. In my experience starting with plants that were grown in nurseries or in dirt is just a recipe for getting pathogens into your nutrient and causing problems for all you plants. Starting with sterile media and seed minimizes the chance of problems developing. Think clean room. You don't have to be too excessive, but care will ensure that your plants get off to a great start.

Just for fun one year I took a plastic tub and turned it into a baby continuous flow system and used it to start plants. It was fun and easy. I took a very small pond pump and used it to pump nutrient to the cover of the tub and cut a hole in the other end and ran it slightly tilted. The only slightly annoying feature was that the algae liked it even through it was flowing continuously and I got a little algae build up on the cover. The plants liked it to though so it was a fun way to get my plants started.

Wednesday, August 13, 2008

Getting Your Plants Started and Helpers

Once you start out in Hydroponics it's remarkable how many friends show up to help out. Grandchildren are particularly fascinated by what you're doing there grandpa? Here in the Shenandoah Valley of Virginia the first day you can be sure it won't freeze is somewhere around May 18th, although I've occasionally been surprised even then.
The picture above shows me putting seeds into a bunch of rockwool cubes to get my tomato plants started. I've done it a number of different ways, but one of the easiest is just to put them in a tray and put some diluted nutrient, about a quarter to a half of the concentration you'll use when the plants are mature and let the plants start in the rockwool.
Generally what I do is soak the rockwool ahead of time just because they say you should (I've never known it to make much difference). Then you can let the plant sprout on its own steam. There is enough nutrient in the seed to get it going, but then you'll want some nutrition once it sprouts.

Tuesday, August 12, 2008

Compounding Your Own Nutrient

I think I mentioned before that when I first started out doing hydroponics I thought compounding my own nutrient would be really neat. I enjoyed high school and college chemistry. My dad used to tell stories about some of his chemical escapades ranging from making gun powder to creating dots of something like nitro-tri-iodide and putting drops of it on the marble floor near the chemistry lab.
So when I first started I thought, "Gee I can mix chemicals!" But there is a lot of math involved. I thought I'd just give you a touch so you'll have the idea.
Nutrients are given in ppm (parts per million). That sounds a little threatening, but it really only means something like 1 mg (milligram, a thousandth of a gram) mixed into a liter of water (1000 grams of water is a liter). See that wasn't too awful.
It gets a little worse when you have to calculate the ingredients available to the plants when you mix various nutrient compounds into the water. Take Calcium Nitrate (Ca(NO3) 2) as an example. If you want to end up with 100 mg of Ca (Calcium) in the nutrient and you're using Calcium Nitrate you have to add up the atomic weights to get the molecular weight
  • Ca = 40.08
  • N = 14.008, and
  • O = 16.00
But there is only one calcium atom while there are two nitrogen and six oxygen atoms. So the total molecular weight of Ca(NO3)2 is 164.096. So it takes 164 milligrams of calcium nitrate to get 40 mg of Ca and you get 28 mg of nitrogen with it in the nitrate ions. To formulate a total nutrient solution you have to mix a number of water soluble salts into the water in just the right combination and amount. Once you fool around with it a bit you decide if you just want to grow tomatoes that you should leave it to the experts.
I'm always reminded of making a telescope because you want to look at the stars. I had a childhood friend who started doing that and got hooked on making telescopes. The only time he ever looked at the stars was to test his telescopes by looking at double stars.
I need to credit Howard Resh's Hydroponic Food Production for the discussion on calcium nitrate.

Monday, August 11, 2008

The roots follow the nutrient

One of the things that surprised me a lot when I first started doing hydroponics was the extent that the roots grew. The tomato plant's roots would follow the flow of the nutrient and each plants roots would become entangled with the plant down stream of it. The tomato plants that were nearest the nutrient tank would grow roots that followed the nutrient right down into the tank.
It was common to have root masses that towards the end of the growing season in September would totally fill the 4" PVC pipe so that the nutrient would get close to running over the side right out of the holes in which the plants were set. I have a picture of myself pulling out a combined root mass something like six feet long.
One thing I discovered is that if the nutrient flowed more rapidly it seems to stimulate more root growth than if it flowed more slowly. So after the first couple of seasons I cut down the flow rate of the nutrient appreciably by limiting the flow into the tubes to a 1/4 inch feed line. This slowed down the growth of the roots so that I didn't get channels filling up and threatening to overflow.

Sunday, August 10, 2008

The Miracle of Growth

One of the really fun things about hydroponics gardening is seeing the transformation of your system as the growing season advances. Here's a picture of the one-third Starburst. I called it that because fully expanded it would have nine channels, so the three shown here are one third of the system. Of course with nine channels the tank would probably have to be bigger since even at this size the tank tends to go down a lot during the day unless you run the system with automatic dosers and keep the water topped off with a float value.
Before and after says it all though doesn't it? Wow!

Saturday, August 9, 2008

Your Local Hydroponics System Supply Store

You can find all sorts of wonderful things to make your hydroponics system at your local Hydroponics System Supply Store (read Lowes, Home Depot, Walmart, and stores that handle all kinds of plastic bric-a-brac.). In this picture from 2000, you see the nutrient tank (a plastic trashcan), PVC tubes used for channels and the system support frame, a plastic gutter used as part of the return system, gutter extensions usually used to run water away from the house at the bottom of rain spouts, and little plastic covered lidded container pressed into service to protect the conductivity meter from the rain. There is an automatic hobby doser mounted on the side of the tank and the hose is connected to a float valve.

There are all kinds of wonderful things in the stores that can be turned to use in making your systems. That is part of the fun of it, turning conventional things to new uses.

Friday, August 8, 2008

Bringing it All Together

Another approach to channel organization is the "Star" system which arranges the channels radially. The good news is that this solves the problems posed by the parallel organization. The bad news is that it has some problems of its own. The solutions are:
  1. You can get to all the channels much more easily.
  2. The nutrient return to the tank is easy since they are all arranged radially.
  3. You can manage each channel individually since they are all fed individually.
So what's not to like? Well into every life a little rain must fall, as my mother used to say. The Star-architecture has a few issues:
  1. Each channel requires its own support structure. I solved that with the pedestal mount which works pretty well and is fairly each — but you need two per channel.
  2. Distribution of the nutrient requires a nutrient feed tube for each channel. I do that by bungie-cording them onto the channel, but
  3. That requires a manifold to distribute the nutrient. You can see it sticking up there out of the tank. Each channel nutrient distribution tube has it's own feed. These can be "turned off" by removing the (whatever they call'em — thingie) and replacing it with a plug which screws in.
  4. Notice the black stuff (that's a ground cover plastic and it is essential) — You have to keep the nutrient dark (as in let no light in) or you will be the charitable host of algae which will eat your nutrient and gum up your pumps.
  5. Oh and did I mention the overhead structure which just got more complicated too. Each channel needs an overhead structure from which to suspend strings on which to attach and support the plants. Like the channel support this requires two verticals per channel.
So all is not a rose garden. But still the star system is cool. The header has a picture of a six tube star system as it was put into practice. I've obviously inspired some imitators since other hobbyists have sent me pictures of their stars. Once you've created the pieces (which are mostly just cut to length and drill a few holes) you can put the system up in about an hour or two. It comes down more quickly but you have to clean out the channels and as experience has taught me, sanitize them as well or you're inviting plant diseases in subsequent years.

Thursday, August 7, 2008

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.

Wednesday, August 6, 2008

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!

Tuesday, August 5, 2008

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.

Monday, August 4, 2008

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.

Sunday, August 3, 2008

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.

Saturday, August 2, 2008

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.

Friday, August 1, 2008

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.