Aqua and Hydroponics

Lately my interest has peaked in aquaponics and hydroponics. As a hydrogeologist, I like toying with the concepts of dissolved nutrients in water, and how the parameters of water can influence the biosphere.

Hydroponics

Hydroponics is a method of growing plants without soil, using nutrient-enhanced water.  Commonly, the plants will root in a growing medium, such as sterile pellets, or be embedded in floating mat.  Hydroponics is a form of geek gardening that allows for precise control of most of the variables controlling the viability of the plants.  You can decide the exact nutrients that the plants get and decide how frequently the root system is exposed to water.  Some gardeners prefer continuous root exposure to water, while others alternate between cycles of saturated and unsaturated or use a drip line to provide water.  

A simple drip hydroponic setup using a rain gutter.  The gutter is usually filled with a growing medium like expanded clay pebbles or rock wool.  Nutrient-rich water is pumped and dripped to each plant.  The gutter is oriented in a way that allows for gravity drainage of the water back to the bucket. From: Gregory Axt.

Some of the lease expensive hydroponics setups use PVC or rain gutters to hold their plants and network water. The PVC system pictured is likely a Nutrient Film System, where a shallow, slow-flowing stream of nutrient-enhanced water is circulated through the pipes. From homestead-hydroponics.

A basic ebb and flow hydroponics setup, where the growing medium is periodically flooded and drained.  Nutrients are generally added in the reservoir. From hydroponics simplified.

In many hydroponics systems, the plants are suspended using a plastic mesh net pot.

A Water Culture System.  The plan roots are continuously saturated in nutrient-enhanced water. This is one of the least expensive hydroponics systems to build, as it only requires an air pump and an air stone. I have seen people build small water culture systems that only require a coffee can or five gallon bucket.

Generally, an air stone is introduced into the reservoir to add oxygen into the water and to prolong dissolution of the nutrients.  While plant use carbon dioxide for photosynthesis, their roots require oxygen.

Aquaponics 

Aquaponics is a type of hydroponics that uses fish to provide the nutrients required by the plants.  Oftentimes, a special type of fish food is used to help promote an ideal nutrient balance for the plants.  Commercial-scale aquaponics systems actually grow both edible plants and edible fish.  However, most smaller-scale home aquaponics systems use less palatable fish such as goldfish.  I like aquaponics because it promotes the concept of symbiosis, where plants rely on the fish waste for nitrates and the fish need the plants to eliminate/reformulate those nitrates.  Because fish are providing the nutrients for the plants, you want to use high quality fish food designed for aquaponics.

Basic aquaponics setup from DIY aquaponics website.  This is a variation on the ebb and flow system and includes a self-draining bell siphon. Here are some excellent instructions on how to build a self-draining bell siphon for an aquaponics ebb and flow system.

This is an excellent graphic of the aquaponics nitrogen cycle from the Backyard Aquaponics website.

The size of aquaponics systems can vary dramatically.  Backyard Aquaponics offers free plans on how to build these cool barrel systems.

The addition of an aquarium water heater to an aquaponics system could help enhance yield and growth rate, as well as growing season.

Aquaponics relies on bacteria to convert the nitrate into a usable form.  Creating an area for those bacteria to grow makes these systems more effective.  This guy used a filter that promotes multiplication of these bacteria.

For more information about aquaponics, check out this awesome guide by Backyard Aquaponics.

Colorado Aquaponics also wrote a nice presentation on the subject.

Aeroponics

A variation on hydroponics is aeroponics, where roots are exposed to air. This technique can enhance root growth.

A cross section of the Tower Garden aeroponics system.

An aeroponics setup from user GpsFrontier on the hydroponics-online forum.

Links

Window Farms hydroponics
Hydroponics setups for cheap on Instructables.
Another aquaponics manual
Aquaponics nutrients
More on aquaponics nutrients

Geek Gardening

Introduction

As a scientist, I am continuously seeking ways to monitor and quantify my world, including my garden.  After coming across this book on Amazon, I was enticed to search out the Geek Gardening community on the internet.

While this book does not incorporate computer programming (read below), it does apply science to improve your garden yield.  A combination of tips from this book and creative microcontroller programming could result in some really cool automated garden projects.

I am in the process of learning how to program/write in Python scripting language.  Like with gardening, I am very new at it and have a lot to learn.

Fortunately, there is a growing community of those who like to automate and quantify their gardening practice.  Most of the projects I have noticed involve the implementation of some variation of the open-source Arduino microcontroller or the Raspberry Pi mini-computer.  The simplest configurations of this marriage of programming and gardening usually involves creating a script to detect and react to a lack of water in the gardening system.  All of these projects are open source, which allows for your own creative input on how to improve them.

Gadgets

Garduino

The earliest implementation of programming to gardening that I have observed is the Garduino.  There is a how-to of the Garduino is on the very awesome website Instructables, which is geared towards the "maker" community.  Garduino can be modified to continuously measure humidity, temperature, and light.

The basic Garduino layout consists of using nails to determine soil moisture (electrical resistance of soil).  A pump, controlled by the Arduino, pumps water into the garden when the soil is dry.  The timing of the lights is also controlled by the Arduino board.  From MAKE magazine Volume 18.

Growerbot

For those of you not ambitious or brave enough to assemble a breadboard and program an Arduino by yourselves, there is the Growerbot, which uses the same technology, packaged in a cool wooden box. Growerbot is the child of a Kickstarter campaign.  The Growerbot comes with an advantage of being wireless internet ready, which can allow you to get instant online feedback on the status of your garden.  With the know-how, the Garduino concept can also be wi-fi enabled.

For $195, you can buy the preassembled and preprogrammed Growerbot.  For $120, you can buy the unassembled version. 

Botanicalls

The Botanicalls project is a small, leaf-shaped board that measures the soil moisture of your houseplants and sends you a Tweet when the soil is dry.

Although they deserve kudos for the design, the Botanicalls boards have a few serious drawbacks: they require a hard-wire power source, no wireless internet connection, and they are not made for outdoor conditions.

Ecoduino

The Ecoduino is another kit with the same intentions as the Garduino.  It's main components are a pump and soil moisture probe.

Open Sprinkler

Another extremely cool project is Open Sprinkler, an open-source sprinkler controller made by Ray Wang and Chris Anderson!  Ray has created a ready-to-use sprinkler controller and mobile web apps so that you can adjust your sprinkler system using your phone.  Open Sprinkler allows for 8 stations by itself.  With an expansion breadboard, the controller can handle up to 48 stations.  The community associated with Open Sprinkler has contributed modifications to the controller that allow the controller to check online weather reports to adjust watering accordingly

The newest preassembled edition of Open Sprinkler is $149.

Application

After finding some of the cool gadgets and kits, I wanted to see who was actually applying the technology to grow food.  Most of the automated gardens I found used aquaponics to grow their food.  Aquaponics is using circulating water to grow plants, usually in a gravel or floating mat medium.

This guy is passionate about aquaponics and garden automation:

This man is passionate about extreme urban gardening.  His website is Kijannigrows.

Here is another inventor implementing a similar variation of aquaponics.

One of the biggest applications of geek gardening is that of the marijuana growers.  They have definitely made plant growing a science, and many have embraced the route of gardening automation.  Many farms are indoor gardens, where every variable (including carbon dioxide, temperature, humidity, and nutrients) is closely monitored and controlled).  While I personally do not partake in the farming and growing of illicit drugs, I am impressed at the "high" bar that the growers set.  With the legalization of recreational marijuana in Washington and Colorado, hopefully growers will be more forthcoming with their techniques, as many of those techniques are directly applicable to vegetable gardens.   High Times included an extended article on the application of automation to indoor gardens. Tomato growers have a thing or two to learn about maximizing flowering of tropical plants.

Expanding the Concept

So, what can be done to improve the geek gardener community?  There are many ideas that I have that could be implemented.

As far as I can tell, there is a slight disconnect between the indoor and outdoor technology.  I think it would be cool to tie the concepts soil moisture monitoring to the mass watering capabilities of the Open Sprinkler.  Also, it would be a good idea to create an automatic soil moisture meter that measures moisture at different depths in the soil at the same point.  With information about the rate of water application, a multi-depth soil moisture probe could allow one to estimate water infiltration rate in the soil, and where a majority of the soil moisture resides.

Another interesting aspect of quantification would be fertilizer application. I would think that the easiest way to implement automation would be to incorporate liquid fertilizer in the watering system.

While soil moister is an important variable for maintaining plant health, it is not a direct measure of plant health.  Incorporating an infrared (IR) camera into the automated system would allow the gardener to continuously measure plant health.  IR cameras are increasingly becoming more accessible and are readily implemented by Raspberry Pi minicomputers.

One cool implementation of an inexpensive IR camera is the infragram photography project. The infragram photography project is another child of Kickstarter.