Ray's Journal for the Hydroponic Newbie
So, you're a "newbie" to hydroponics. I was a hydroponics "newbie" about twelve years ago. At the time I felt like a small child underfoot asking all kinds of annoying questions like: "Why do you do that?" or "How do you do this?" It's a real blessing when you find someone who sincerely wants to help.
I intially didn't like gardening because I was not very good at it and didn't like digging, weeding, spraying and all those other things. But I love tomatoes. I'm not entirely sure what turned me on to hydroponics, I'd known only a little about it from science-fiction, but nothing very useful. But whatever it was I quickly got intrigued by the idea of growing things without dirt or weeds or any of the other ordinary paraphernalia of gardening.
Most of the people I run into are fascinated by the idea, but they think it must be too hard. "Oh you're a scientist. That technical stuff is easy for you," is the kind of thing people often say to me. The secret (and it's not really a secret) is that hydroponics is easy and fun.
Think about gardening: you need seeds, light, soil, water, and if your soil isn't very good you need fertilizer. You dig and prepare the soil, then you plant the seeds and carefully tend them as they grow - providing water, nutrition, and weeding. Hydroponics changes two things: 1) it gets rid of the dirt and 2) let's you take complete control of the nutrients the plants receive. What could be better than that? Dirt is–, well dirty, and you probably don't know what's in it, so isn't it better to take complete control of your plants? Anyway I think so.
The Simplest Hydroponic System
There is no end to the different ways you can do hydroponics. If you like to tinker around that's one of the joys of this hobby. First, you need something to start the seeds in. I use little one-inch Rockwool cubes. Rockwool is sort of cotton candy made out of rock. It's used as plumber's insulation but you want to get it in a hydroponics grade to make sure there are no impurities. It's readily available in sheets. You can start the seeds right in the Rockwool cubes without any nutrient, but as soon as the plants sprout you'll want to add nutrient at reduced strength. Then as the plants grow, you gradually increase the nutrient strength.
You don't have to use Rockwool cubes of course. You can use those little peat pots or you can take disposable plastic drinking cups and put in some perlite or clay pellets or mixtures. I often do that for cucumbers, which seem to like a zone between their roots and the liquid nutrient.
The simplest hydroponics system is a bucket with a top which has a hole cut in it to put a cup holding the plant. Then you have rags going into the liquid in the bucket. The nutrient wicks up the rags to the plant and the plant's roots follow the rags down into the nutrient. You need to replenish the liquid in the bucket at regular intervals and if the plant is a kind that grows tall, you'll want to put some kind of support up that the plant can grow on. That's it! It's called a "wick system" because the rags wick the nutrient to the plants, at least until the roots grow down into the nutrient.
I've done wick systems indoors and outdoors when I didn't want to be bothered by pumps and electricity. They work well, especially if you only want a few plants. The wick system is an example of a passive system. Nothing to do but come by and check the liquid level and top it off and add a little nutrient whenever it needs it.
Other Kinds of Systems
There are many kinds of hydroponics systems and often one of the hardest decisions is which kind to try out first. The first year I tried hydroponics I found myself making an example of each kind of system as I discovered them and putting them out on my side-deck. My wife was not too happy since I'd promised to only use part of the deck and then as the late Spring turned to Summer the deck was quickly covered with more and more systems.
Typically the two things that vary with systems are the medium and the nutrient delivery. The medium is what you put the seeds into. The nutrient delivery is how the nutrient is delivered to the plants. We've mentioned one kind of passive system called the wick system. Another kind that is similar is the float system. This works extremely well with light plants that don't grow too high like lettuce and basil. To make a float system you take a sheet of Styrofoam and cut holes in it for little plant cups and then float it on the nutrient.
Active systems deliver the nutrient with pumps and flow the nutrient over the roots. These tend to come in two flavors: continuous, and flood and drain.
The typical continuous systems are NFT (Nutrient Film Technique) systems. I've done more of these than any other kind because the plants seem to flourish so well in NFT systems. Typically the plants are put in channels (tubes) and the nutrient is pumped to the high end and gravity flows back to the tank where it is then recirculated by the pump.
Flood and drains systems require a timer because the system is flooded and then drained. I've only done flood and drain systems a couple of times because it requires adding additional components (the timer) and typically requires more medium to retain moisture between flood cycles. Some plants likely prefer these kinds of systems, but not tomatoes and cucumbers and peppers which I've mostly grown.
The Hard Part (which really isn't hard)
So if it's so easy, what's the hard part? There really isn't a hard part but there is a slightly tricky part and that's keeping your nutrient adjusted correctly. You mix hydroponic fertilizer with water to feed your plants. The easiest way to get the nutrient is to buy it. When I first started out I looked into compounding it myself because it looked like fun and you can do that if you want to. There are all kinds of books that will guide you in that adventure. If you just want to grow things though it is much easier to buy a good nutrient and then follow directions. Typically you mix it with water in the right amounts and you get nutrient solution. What's hard about that? There is that little "right amounts" thing, and also when the plants are using the nutrient you can't tell how much they're using.
Enter instrumentation - you need a conductivity meter to measure nutrient strength. If it is too weak you add nutrient concentrate. If it is too strong you dilute it with water. The conductivity meter is a good guide. But since plants can selectively consume nutrients it is a good practice to dump your tank every few weeks and start over fresh. The instrument will cost somewhere in the $50 to $120 range depending on type and features. You also may need to measure pH, that is acidity. That will vary somewhat by region. I've never had to do it because my plants grow just fine without it. If you do need to do it, it is just another nutrient adjustment but it's a bit more complex. Generally the acid that is used is a diluted phosphoric acid which delivers a nutrient while lowering pH.
That's pretty much all you need to know to get started. Look at the pictures of some of my systems, or go out on the Internet and scout around. There are oodles of hydroponics practitioners out there.
LINKS TO GET YOU STARTED
The Growing Edge's Basics page - http://www.growingedge.com/basics/start.html
You can always hit my blog - http://theweedlessgarden.blogspot.com
Virginia Cooperative Extension - http://www.ext.vt.edu/pubs/envirohort/426-084/426-084.html
Illustrations of basic hydroponics systems - //http://www.simplyhydro.com/system.html
Grower's Guide to Plant Nutrition (see page 39 for Hydroponics Steiner Solution) http://www.ghsinc.net/pdf/53120-Total-Gro-book.pdf
