needmoreCOFFEE: March 2012

HYDROPONICS. in a nutshell

(Im not responsible for this analysis - I just found it to be a really, really good one. I had no idea what on earth hydroP was, but after 20mins reading this I had a very good idea :-)!)

The primary types of Hydroponics systems are NFT, Wick, Water Culture, Drip, Ebb & Flow (Flood & Drain), and Aeroponics. There are many variations on the themes but they all pretty much fall into one or other (sometimes several) of those types.

I've listed below a basic description of the various types

NFT - Nutrient Film technique

In the NFT method of hydroponics the plants are suspended above a constantly flowing stream of nutrient solution, which in practice is some 1 - 3mm deep. The plant is suspended above the solution usually in a rock wool cube within a mesh container, with the roots dangling down into the solution.

This is a successful technique often used by commercial growers. There are definite advantages for both the commercial grower and amateur. There are no drippers to block, but on occasion the roots will grow so well that they can block the channel, resulting in if not checked a total loss of nutrient and ultimately dead plants.

Filtration of the waste water is important in this and all hydroponic systems, it must be filtered of root debris etc before it is returned to the holding tank, otherwise you can expect blockages.

The system uses a pump so it is reliant on a constant source of electricity.

Wick System

The Wick system is arguably the simplest of the hydroponic system types. There are no moving parts (drippers pumps etc) so it is referred to as a “passive system”.

The nutrient solution is drawn up into the growing medium from a reservoir below the pot, via a form of wick.

There are a huge number of applications of this type, you can very probably buy plant pots based on this system in your local hardware shop. The disadvantage in many of it’s forms is that the nutrient is not moving therefore it can become deoxygenated or stagnant. An air stone is a good solution, but there is often not enough room for that in the reservoir of the smaller pots.

Large plants can suffer in this type of system as they might draw more nutrient than the wick can supply. Thus drying out the plant. It does work very well in practice though.

Water Culture

Again a very simple hydroponics system. The plant is suspended in the nutrient solution, usually using a floating polystyrene/Styrofoam platform.

Sometimes the water is left to stand but it is better circulated and aerated by an air stone. This system is scalable and has been used on a very large scale to produce leaf crops such as lettuce or other small fast growing crops in a commercial environment.

The advantages are that in the floating form the plant roots are always in the nutrient regardless of the level. You are therefore not at the mercy of the electricity supply, where in a system such as NFT the plants can die.

This system is not however suitable for large plants or plants that take a long time to grow.

Ebb And Flow - Flood And Drain

The ebb and flow system is a non passive system, it requires a pump of some type.

The plant is suspended in a vessel were the roots are regularly subjected to a flood of water which covers the roots. The water is then allowed to gradually drain away thus oxygenating the roots.

This system is reliant on electricity so that a constant supply of water can be delivered. In a cold climate that is not such a problem, but in a warm or hot situation a relatively short period without water will dry the roots and kill the plant. A water absorbing medium to support the plant can help, but will add to the cost of operation. That said I have used this type of system in a very hot climate with huge success.

Large plants such as rhubarb, tomatoes and even potatoes grow well in this type. Lettuce do not do as well as in some other types of hydroponics system.

Drip Systems

This is one of my favorite types of hydroponic system and is probably the most widely used type.

The plant is grown in a pot or vessel containing a free draining medium such as grow rock's or perlite etc and the nutrient is dripped in to the pot. The nutrient can then be caught at the bottom of the pot and returned to a tank were it is then eventually recirculated back to the plant. Alternatively the nutrient is not caught and allowed to run to waste.

The delivery of nutrient to the plant is often controlled by a timer, a constant delivery of nutrient is not really necessary. You can make a very simple manual version of this system using three buckets and a dripper set to drip infrequently. At the other end of the scale i've seen Banana trees grown hydroponicaly using the drip method.

The down sides of this type of system is that the drippers are prone to blockage and need at least daily checking. Also the plants will absorb widely varying quantities of nutrient and can change the pH of the nutrient. Regular checking of this is important.

A none recirculating system avoids this problem but on a large scale this type can be environmentally challenging and must be disposed of somehow and nutrient costs are vastly increased.

Aeroponics

Aeroponics is in some ways the ideal concept of a hydroponics system, but like most seemingly perfect things it proves in actual fact to be flawed.

The principal is simple, a plant is suspended above a vessel with the roots hanging down in to the chamber below, where they are misted with nutrient. Thus providing food for the plant and plenty of oxygen.

In practice this type of system is extremely reliant on a reliable power supply, because it is at the mercy of a constant misting of nutrient.

But the biggest problem is that if you mist a solution of salts, it will inevitably condense on the jet and ultimately block it. Regular (even hourly) inspection of the jet is essential as the plant roots will dry out quickly. My brief experiments with this type of system were a miserable failure after just a few days.

However I would be delighted to see an inexpensive working Aeroponics system, there are several around that are way out of my budget.

So there you have it, the six types of Hydroponics system. In my experience there is no perfect system, but for me the drip method comes close to it, it is I think the best system type for a beginner.

That said a drip system is a compromise, it is not ideally suited to all of the plant types, in commercial production they suit the system to the plant and achieve even more amazing results.

Cute huh?
Well... yes, but:

Is this not actually a more accurate ideology of what we have come to think of as 'green architecture' than one might think? What I'm saying is that the more research I do, the more I look into this new trend that is going green I cant help but wonder is it really a practical, feasable and above all economically viable way forward? Like the image above the whole going green phase, at least in my opinion, is more of a cutesy stereotype that opens itself to dreamy visions of a paradise-like future than it is a realistic look at the characteristics and restrictions imposed on us by modern day architecture.

Its fine and well to be perched in your mothers basement day and night dreaming up skyscrapers emerging from the oceans clad in lush green lawns and roofed with the recycled exrement of domestic kitty cats. But venture upstairs at some point and spend some time in the real world and you will actually develop an understanding of how the grass isn't always greener on the other side of a vertical wall. Actually within a few months it's usually dead.

The question I'm asking is really can we acheive even an inkling of our proposed sustainable goal while still residing within the realm of plausable, recognized construction AND will the the client pay for it? I think in essence at the end of the day GREEN is like physical exercise. As long as it plays a role in our life - within the fabric of our way of thinking, we are able to improve the way we live in this world and the means with which we interact with it. If this is true on even a minor scale then all our efforts certainly count for something, or at least thats what we can tell ourselves.