Wednesday, August 31, 2011

Media Bed Vs Raft Bed

     The first thing you have to do when getting into aquaponics is to decide which type of system is right for you.  It can seem like a tough decision, and most people you could ask have a favorite for one reason or another.  It's important to pick a system design that'll work best for you.  In this article I'm going to discuss media bed systems and raft bed systems.  Most home growers pick one of these two designs, so we'll focus on them.
Raft Bed system
     I prefer raft bed systems.  Remember that this is just my preference, but I'll try and give a good argument for them.  Raft beds utilize a bed, usually one foot deep, with a raft floating on the water for plants to grow in.  Net pots, rockwool, or another substrate is planted in and then placed in holes in the raft.  The ratio of fish tank to raft bed volume is 1:1 or 1:2.  The great thing about raft beds is that the stocking density of fish in the system is determined by the total water volume in the system.  In example, a 100 gallon fish tank in a raft bed system can be stocked with more fish than a 100 gallon fish tank in a media bed because of the extra water volume from the raft beds.  This is important to keep in mind if you want to harvest fish for their protein.  Another benefit of extra water volume is that there is more of a buffer when it comes to water quality.  Swings in pH and temperature are less likely.  There are more components in the raft bed design, which leads to a higher initial investment.  These designs utilize a mineralization/clarification tank to collect and filter out solids.  This will keep the solid waste from your fish tank out of your raft beds, where it can coat plant roots and hinder nutrient uptake.  But the maintenance on these systems is very simple.  You feed your fish, flush solids about once a week, make sure the water is flowing properly, and add amendments once a week.  It's not hard to maintain a raft bed system.
Media Bed system
      Media bed systems typically have a more simple design, which means it costs less to start up a system.  This can be a huge factor for some.  The downside is that all the solid waste from the fish ends up in the media bed, which acts as your filter.  Media beds function more efficiently when fish are stocked at a lower density because there are fewer solids this way.  If your main concern in aquaponics is plant production this is less of a concern.  And, in my experience, media beds benefit from having a mineralization tank in the system.  One of the advantages of media beds is that planting in a media bed is more familiar to people than planting in a raft.  It also provides more support for the plants if the area the system is in gets a lot of wind.  The media bed is usually about waist high, too.  This is a great feature for anyone who wants to garden without all the kneeling and bending over.  There is less maintenance in a properly designed and stocked (fish) media system.  The media bed acting as a filter cuts back on the need to remove solids manually.
     Either of these two systems are a great choice.  Like I said, it just depends on you and what you want.  I hope this helps you make a more informed decision on which system is right for you.  If you need any more information or advice shoot me an email and I'll get back to you as soon as I can.

Brendon Tripp
Trinity Aquaponics

Tuesday, August 30, 2011

"Aquaponic Food Production" Book Review

My copy of "Aquaponic Food Production"
     When I took my first Aquaponics course "Aquaponic Food Production: Raising fish and plants for food and profit" was chosen as to be the textbook.  It's one of the few books available on aquaponic food production, and it's a pretty well rounded book.
     The book explains what aquaponics is and how it works in wording that is very easy to understand, even if you have no background in aquaponics.  There is even a chapter on the history of aquaponics, which I like since I'm a big fan of learning about history.  The types of systems most often used and the components used to build these systems are discussed to give the reader a better understanding of how the systems function.  Chapters on plant and fish selection help the reader choose what crop and what species of fish they'd like to grow in their system based on their needs.  There's even a pretty good chapter with information on starting an aquaponic business.
     There were some issues I had with the book.  When explaining raft bed systems it's mentioned that there are set ratios for raft to fish tank volume that are very important to follow.  This information is then never mentioned, in any way.  The stocking rate of fish to water volume or fish to plants is never mentioned, either.  And, oddly enough, the only time rates for feeding fish are mentioned is in the chapter on the different systems, not in the chapter on fish feeds and feeding.  In my mind this is information that should be easy to find and made very clear.  I can't help but wonder if the information was purposely left out.  How could you forget state a ratio that you just mentioned was extremely important?  And pest control was not adequately discussed, in my opinion.  There is a bit of information on pests, but not much on what to use to deal with them.  Since there are a lot of pest control products that can't be used in aquaponics (many inorganic products will kill the fish) pest control options should have been discussed in more depth.  If it weren't for the lack of this group of information I'd say that this book would be a fantastic choice for an all-in-one manual for aquaponics.  Luckily, the information that was left out is readily available on the Internet.  If you're reading this post, then you can surely find that information.
     All in all, I would recommend this book to newcomers and more experienced aquaponic enthusiasts alike.  It's got a lot of great information and I've gone back to it several times to get answers to some of my questions.  But, don't expect it to be the only book you'll need to get going in aquaponics.  Coupled with the Internet this book will help you out a lot, though.

Monday, August 29, 2011

Rockwool as a Substrate

     Rockwool is a commonly used substrate in hydroponics and aquaponics.  If you have never worked with it the best description of rockwool would be to say it looks and feels somewhat like insulation.  It isn't hard on your skin to work with, though.  Rockwool manufactured for growing purposes is made from basaltic rock.  The rock is heated to its melting point and spun into fibers.  A binder is then added to the fibers and they are compressed into slabs.  These slabs are then cut to a variety of sizes which serve different growing purposes.
     Rockwool is great for aquaponic purposes because of its water retention and air holding capabilities.  It's also very clean and easy to work with.  I use rockwool in my raft systems because it won't break down when constantly moist and is very inexpensive.  Seeds can be germinated directly in the rockwool or seedlings can be put in rockwool once they've sprouted.  It's a very versatile medium.  There are disadvantages, though.  The earth must be mined to get the basaltic rock required for the production of rockwool.  Many would argue that this makes it an unsustainable product.  It naturally has a higher pH, and it's recommended that you soak rockwool in a solution of lower pH to neutralize it.  I've never adjusted the pH and have never run into any problems, though.  Because it's manufactured from rock it won't break down.  So, once used, disposing of rockwool is tough for someone striving to be very green.  Putting it in a landfill is not acceptable for some people.
     There are a couple of viable alternatives to rockwool.  The best alternative, in my opinion, is to use net pots and hydroton or growstones.  This way when plants are harvested the substrate can be cleaned off and reused.  Seeds can be started in coco coir or a similar substrate and planted in the net pots when they've grown an inch or two.  There is also a product called Oasis foam that is mostly used in the floral industry.  It works, but I'm not fond of it.  The foam breaks apart easily and the cubes are too small, in my opinion.  I'd rather use rockwool than Oasis foam.
     If I had to pick my top two choices for raft and NFT system substrates I would choose rockwool or net pots.  Rockwool is a great product as far as using it in a system goes.  But, long term it may not be the best choice.  And it is another financial input since you have to buy new slabs occasionally.  Net pots will cost less over time and are the better choice for someone who wants to be as green as possible.  More information on rockwool can be found at the Grodan website.

Sunday, August 28, 2011

Aquaponics during Emergencies

     When things are going well and there are no troubles on the horizon it is easy to take for granted the many luxuries in our lives.  Electricity is one of the easiest aspects of modern life that is taken for granted every day by many people.  When you're maintaining an aquaponic system you can't afford to take it for granted, though. 
     Once the power goes out key aspects of an aquaponic system's life force are cut off.  Without the air pumps no oxygen is being provided to the system.  The fish will soon deplete the oxygen left in the water and begin to die.  The amount of time this takes depends on how much oxygen was in the water and the ratio of fish to water.  The more fish in a system, the faster the oxygen will run out.  This isn't only a financial loss.  More importantly, it's a loss of nutrient for your plants.  If the fish in a system die and are not replaced quickly crop production will take a tremendous hit.  The fish aren't the only living organisms in the system that need oxygen.  Both the beneficial bacteria and plants need oxygen to survive, as well.  The loss of beneficial bacteria in a system is just as awful a loss as is the loss of fish.  The bacteria are needed for the conversion of toxic chemicals from the fish to useful nutrients for the plants.  Without the bacteria a system's water can become toxic quickly.  This is especially true in a system that has been running at the maximum stocking density of fish.  And, while plants may be cheaper and easier to replace than fish it does take time to propagate from seeds or cuttings.  If a crop dies then so does a large part of your filter.  Nitrates are much less toxic than ammonia and nitrites, but at high levels it can still kill your fish.  If you have to wait a couple of weeks to get plants back into a system it can cause a lot of trouble.
     So, how do you ensure that you won't run into these problems?  You need a plan for emergencies.  The best option is backup power.  A generator can run an aquaponic system easily.  However, in some emergencies getting the gas to run a generator can be almost impossible.  Having a store of gasoline for the generator can alleviate some of the pressure of going out to find gas.  Renewable energy is another fantastic option.  It is definitely a more expensive option than a generator, but the benefits may outweigh the cost in your situation.  Solar panels or wind turbines storing power in a battery bank can offer an endless supply of electricity for an aquaponic system.  And renewable energy isn't only going to work for you during emergencies.  It works all the time.  This technology can be used to take your system off the grid and save you a little money every month on the electric bill.  If you find yourself unprepared when the lights go off and your pumps stop pumping you can use a bucket to agitate the water by filling the bucket with water from the system and dumping it right back in.  This will add some oxygen back to the water, but it is in no way efficient.  It's also very tiring, especially considering how often you'd have to do it.
     Whatever your situation is it is always safer to have a backup plan for electricity to power your aquaponic system.  If you don't have a plan it can cost you your money, plants, fish and bacteria.  If you can afford solar panels and batteries for a battery bank it'd be my first choice.  If the weather in your area dictates, a wind turbine may be the better choice.  And if you'd rather just have an emergency plan a generator will keep things flowing smoothly, so long as you have the fuel for it.

Vermicompost Bin

Easy, cheap vermicompost bin

     Vermicomposting is a great solution to composting if you don't have a lot of space to dedicate to composting.  You can keep a vermicomposter almost anywhere so long as it's not hot and there's good air circulation.  And vermicomposting breaks down kitchen scraps a lot faster than just composting.
     In case you're not familiar with it, vermicomposting uses worms to break down vegetable matter.  As the worms eat the material in the vermicomposter they leave behind worm castings.  The worm casting can be scooped up and added to soil as an amendment or it can be dissolved in water to make a fertilizer solution.  Plants love the stuff.
     It's very cheap and easy to start.  And the added bonus is that if you run an aquaponic system, the worms from the composter can be used to supplement the diet of your fish.  Worms are high in protein and fish love them.  The webpage linked in the post has great information.  Not only on building a vermicomposter, but on starting it up, what to feed the worms, and troubleshooting.  It's a great article.

Friday, August 26, 2011

Water Usage in Aquaponics

     It's been a week no since Trinity Aquaponics began recording water loss in a residential sized system that we maintain for research.  So far I'm very happy with the results.
     The system being used to collect data is a 400 gallon, 2 raft bed system.  The raft beds together equal a 3' x 8' x 1' grow space.  Measures have been taken to minimize water lost to evaporation, including covering the fish tank and mineralization tank.  I believe that these measures have significantly reduced water loss because of the minimal surface area of water exposed to the elements.
     The average temperature where the system is located has been 97.5 degrees Fahrenheit.  Despite the high temperatures the system has only lost 7.95 gallons over the course of the week.  I'm very happy with these results and have high hopes for the continuation of this research.
     A soil garden of comparable grow space would use this amount of water in a day or two in this area.  A week of recording water loss is not enough time to record substantial research results.  So as the research continues I will update the blog with further findings.  Like I said, I have high hopes for this research and am very excited with the first week's results.

Brendon Tripp,
Owner/ operator of Trinity Aquaponics

DIY Seeding Cabinet

Propagating seeds is one of my favorite parts of gardening.  Knowing that you've taken part in a plant thriving from start to finish just feels good.  And it's always awesome watching a seedling break through the soil.  I prefer to start seeds inside in a seeding cabinet that I made some time ago.  There are several benefits.  For one, I can start a lot of seedling in a small space.  The cabinet has about 1' x 2 1/2' of floor space and is about 3' tall.  It takes up very little room, yet I can start a tremendous amount of plants in it.  A 98 cube slab of rockwool fits in the cabinet easily, and I can fit even more using my preferred method of seeding using coco coir (  I like to call that method high density seeding.  You can plant several seeds in one place and separate them carefully once they emerge and grow to an inch or two.  You have to be very careful with the taproot when doing that, though.

Seeding Cabinet with light on (cabinet can be painted to block out light.)

Seeding tray inside of cabinet.

     Building the cabinet was very easy and pretty inexpensive.  I purchased a short sterilite garage cabinet to house everything.  I attached four light bulb sockets to the top (horizontally to make the most use out of the lights) and wired them using a cheap extension cord.  I won't go into details on that here, but a quick google search or even talking to an employee at a home improvement store will provide you all you need to know.  In the bottom of the cabinet I used a hole saw to drill a passive intake hole for air current.  I also drilled a couple of holes in the shelf that whatever I'm seeding in sits on to increase airflow from the intake to outtake.  Another hole further up on the cabinet created an outtake.  To ensure airflow I used a reused PC fan and a/c phone charger.  The PC fan is wired to the phone charger, which can be plugged into any power outlet.  You simply snip the phone connection off the end of the charger, strip the two wires, and splice them with the two wires from the PC fan.  You may have to switch the wires once to get the right wires spliced together.  Be very careful when doing this, electricity is no joke.  You can hurt yourself very badly if you aren't careful, and I'd suggest searching on google for a more in depth description of how to do this.  The only other thing to do was to get a pack of cfl bulbs and a surge protector to plug the lights and fan into.  I like compact fluorescent lights because they put out a lot of light relative to heat.  With four 12-20 watt cfl bulbs the PC fan will keep the cabinet at just above room temperature.

Lights attached to the top of the cabinet.  The hole in the middle is where the PC fan is.

PC fan attached to the back of the cabinet.

Surge protector with lights an fan plugged in.

     Plug the surge protector to a wall outlet and you're ready to go.  You can now seed whichever way you prefer so long as it fits in the cabinet.  I highly recommend trying out the coco coir method, but there are many options and it's pretty much all about preference.

Thursday, August 25, 2011

Aquaponics in the Texas Heat

     At Trinity Aquaponics we maintain several systems so that our staff never stops learning and so we can conduct our own research on aquaponics in zone 9, the gardening zone we're headquartered in.  Research on aquaponics has been conducts since the '70s, but that research isn't widespread.  The research my company conducted is key to offering our customers here in Houston the advice and information that they need to successfully grow with aquaponics.
     We're in the heat of midsummer right now, and it gets brutal outside.  There are a lot of crops that simply won't grow right now.  But it's crucial for an aquaponic system to have plant growth in the system at all times.  Without plants the filtration is lost and fish mortality is significantly increased.  So, what can you grow the temperature rises?
     Most leafy green crops such as lettuce and cabbage are cool season crops.  If you try and grow them during the summer they are stunted, bolt (stretch and become bitter), or just die.  And fruiting crops such as tomatoes will stop setting fruit and produce much less when things heat up.  Crops that do extremely well are herbs.  Right now our systems are overflowing with mint and lemon balm.  I have several basil plants in the systems that are doing great, as well.  Peppers have also fared well this summer.  Despite the heat, these plants will continue producing for you.
    As part of the research that I run, we've just in the past week introduced pole beans, bush beans, cucumber, and tomatillos to one of the systems in order to record how well they grow and produce when introduced in midsummer.  So far growth has been great, and I will keep updating the blog with the progress of those crops as they continue to grow.  I can state for a fact that tomatillos will flourish despite brutal heat and little water in traditional soil gardens.  I have high hopes for them in aquaponics.
     Even though your options are severely limited in the heat of a Texas summer there are fruiting crops that will produce for you.  And it is a great time for herbs.  If you have a food dehydrator you can stock up on dried herbs during the summer to make more space for fruiting crops come cooler weather.  Peppers can be harvested and canned or pickled, which gives you a supply later in the year while once again making room for other crops.  Now, if you have a climate controlled greenhouse your crop selection won't be limited by temperatures.  But a greenhouse is typically a bit of an investment, so I'd suggest sticking with crops that do well in the heat for most residential aquaponic gardeners.

Tuesday, August 23, 2011

Rain Collection: Making Every Drop Count

     Texas is in what is labelled an "exceptional" drought.  To call it for what it is, it's really bad.  Like "driest 10 month period since 1895" bad.  It feels like there's no end in sight, and I've almost forgotten what rain is like.  Here in Houston we've just been put on water restrictions.  Each household is to only water outdoors twice a week.  It's hard times for turf grass in Texas.  And trees aren't fairing much better.  Memorial park is expected to have some severe damage to its trees, and will look very different in several years.  Maintaining a garden is near impossible right now, but I've been doing very well with the aquaponic systems I have at home.  There has been no shortage of peppers or mint this summer.  One of the most significant advantages of aquaponics is the extremely efficient water usage (95% less water than traditional field farming).  And when that rare rain shower occurs we collect as much of the water as possible to use in the backyard systems.  But, isn't a rain collection system going to put a dent in your pocket?  No, it really won't.

Simple rain collecting.
     In my backyard I've set up a 75 gallon container in a spot that gets a pretty heavy flow of water during rainstorms.  I take off the lid and water just pours into the container.  It fills up within a few minutes if it's a decent shower (and if it lasts long enough).  At that point I run a hose connected to a water pump in the container to a smaller 50 gallon drum (the blue drum on the left in the picture).  Turn the pump on and you're making room for more water.
     This is by no means a large collection system.  And it was thrown together with items I already had around the house, so the investment may as well have been nothing.  But the 125 gallons I can collect during a good shower can last me up to 12 weeks, depending on how hot it's been and how much water my systems have lost.  Typically, I fill up a system with a 4' x 8' grow space once a week with roughly 10 gallons.  Compared to a traditional soil garden I'm practically not using water.  I'm not paying for the water either, which is a big help.  And rainwater is one of the best sources of water you can use in aquaponics, so it's a winning situation all around.
     If you have a backyard aquaponic system, a small garden, or even just potted plants I would recommend setting up some sort of rain collection.  It's as easy as trimming back some gutter on the side of your house and running the gutter into a container that is sturdy enough to hold the water.  And you're really only limited by your imagination.  One container not enough for you?  Then why not set several containers next to each other with plumbing connecting them?  Then all the containers fill up during a rainstorm.  But even if you do just want to collect 50 gallons of water, I'd say it's worth the time to set it up.  Take advantage of what nature is giving you, when she decides to give it.

Owner/operator of Trinity Aquaponics
Brendon Tripp 

Monday, August 22, 2011

Coco coir and seeds

     Planting seeds and watching them sprout is one of my favorite parts of horticulture.  Something about putting a seed in a medium and watching a new life form emerge gets me every time.  I look for excuses to start new seeds as often as possible.  And in my experience I've found coco coir to be one of the most efficient and easiest ways to start seeds.
   Coco coir is made from the fibers in the husks of coconuts.  A quick search on google will give you more detail, but what coco coir is is not what I'd like to focus on right now.  I will tell you that it often comes in a dried, compressed brick.  You add water to the brick and it expands profoundly.  Many indoor garden stores sell coco, but I usually buy it at the pet store.  It's sold in the reptile department as a floor mat.  Go with the bricks.  I've found that the coir that comes in a bag doesn't soak up moisture all too well.  One of the best characteristics of coco coir is that it breaks down very slowly, so it can be reused for quite some time before it has to be discarded.  And at that point it can be thrown in a compost pile.

Pole bean emerging from coco coir

     I seed in coco because it there is less waste.  If you plant directly into planter pots, rockwool, or another medium there will be wasted space or resources if some of the seeds don't germinate.  With coco, on the other hand, little space is taken up during the seeding process and if seeds don't germinate you still have coco for the next round.  The steps I take while seeding in coco coir are as follows:
  1.  Buy a brick of coco coir.
  2. Unwrap the brick and place it in a 5 gallon bucket or large bowl and add water.  The packaging will likely tell you how much to add.
  3. Once the brick has absorbed water and has expanded the coco can be mixed up to ensure even distribution of the moisture.  Then it can be placed in a container for seeding (food storage containers work great).
  4. Using a pen or something similar poke holes in the coco to place the seeds into.
  5. Plant several seeds in each hole and label to distinguish varieties (dates are also useful).  Once planted, the seeds can be covered over with coco.
  6. Place the containers in an area with some light, room temperature is fine.
  7. Monitor the containers for seed growth and to ensure that the coco remains moist.
  8. When seedlings emerge and are roughly an inch long they can be pulled from the coco.  I like to use a knife to loosen the coco around the seedlings and pry them up.  You have to be careful not to damage the taproots or the seedlings will die.  This is also important to remember when separating the seedling from each other.
  9. Plant however you were planning to grow.  The seedlings can be placed in soil, rockwool, perlite, etc.
High density seeding

     Then the coco is ready to be used again.  If you don't need it at the time you can store it in a bag big enough to contain all that you have left over.  I would allow the coco to dry out before storing to cut back on any fungus or mold growing on it.  Using this method you can propagate seedlings in a very high density with a high percentage of success.  Personally, I love this method.  And I certainly think it's a lot better than planting directly into rockwool, which is the medium I most often use for my aquaponic applications.

Owner/operator of Trinity Aquaponics
Brendon Tripp