High Tunnel Aquaponics in Winter

We're entering mid-December and the nighttime lows here in Kansas have been reaching about 15F, well below freezing. The water in the high tunnel aquaponics system has been fluctuating in the 72-80F range, while the air temperature oscillates in the 60-90F range.

The fish haven't been growing much, which is to be expected since blue tilapia grow about 3 times faster at 85F than at 72F. They nevertheless seem very happy and healthy, as you can see in this video:

And here's a peek at the grow bed.  I just finished moving the peppers and transplanting the next generation of lettuce, so it looks a bit scraggly right now.  Should look great in a couple of weeks, though.  The white things in the water on the left are all that remain of some giant bolting heads of lettuce.  I tossed some of the heads in there about a week ago when I was reorganizing, and the little 2" long tilapia in the pool have eaten everything but the tap roots.

Blue tilapia fry are growing fast

Here is some fresh footage of the blue tilapia fry from today:

Late October in the Aquaponics Greenhouse

The lettuce is growing fast, as are the cucumbers and the banana pepper plant. I transplanted some other pepper plants into the tunnel; they're a bit droopy, but should pull through. Interestingly, all of these pepper plants were sowed together outside at the same time. When they came up, I moved the runt inside...and now the runt is far and away the biggest and healthiest. We'll see if its siblings can catch up.

Redecorating to accommodate brooding

I originally designed this high tunnel aquaponics system as a production facility rather than as a brooding system.  This means that I had intended to get all-male fry via Fed Ex every 3 months and to simply grow them out to market size.  That plan was simple: just one big fish tank and one big grow bed.

I have since changed my mind and decided to set up my own hatchery operation to brood my own fry.  A hatchery operation (or, if you prefer not to emphasize h's when they lead off words, "an hatchery operation") has different needs than a pure production system.  These needs can be conveniently met by digging out pools in the grow bed to serve as nurseries, but at a cost of reduced filtration and reduced grow space for plants.

I'm now redesigning my system to accommodate the needs of both a hatchery operation and a production operation.  I can squeeze in a nice hatchery operation if I convert 1/3 of the grow bed into a series of nursery pools, and I've calculated that I can convert 1/3 of the grow bed into fish pools if I decrease the peak density in the main fish tank from 1/2 lb fish per gal down to 1/4 lb fish per gallon. 

Below is a pic of the progress to date. Fry collect in the small pool (aka "fry pool"). When they're about 3" long I'll transfer them to the larger pool (aka "fingerling pool"). After another 2-3 months I'll transfer them to a large pen in the big fish tank for their final growout phase.

So in a nutshell, the cost of adding a small hatchery operation to my existing high tunnel aquaponics system is that I'll only be able to produce about half as many adults.  At that rate, I hope to harvest 200 1.5lb fish every 2-3 months, giving me a total of 1,200-1,800 lbs in annual fish production.  We'll see how it goes...

Female tilapia with her fry

One of the female blue tilapia released a couple hundred fry last night. Here she is with her brood (there's a better-quality version on YouTube if you have trouble seeing the fry):

Found first baby tilapia fry and first baby lettuce today!

Here's the baby lettuce:

And here are the first tilapia fry (about 7-seconds in):

Just planted first aquaponics lettuce of Fall 2011

I cleared out the corn, rearranged a bit, and seeded the whole grow bed with Buttercrunch lettuce.  It looks barren now, but the lettuce seeds will sprout within few days and will quickly turn the floor green.  The sole green you're seeing now is a banana pepper plant.  It was doing well until the last 4 or 5 days, during which time I've kept the door closed in order to warm up the water.  The peppers have started to develop brown spots from the high humidity (I think), but I don't think high humidity bothers lettuce.

I also dug out a 2nd small pool and moved the largemouth bass into it from the 1st small pool (the one closest to the fish tank).  I did this because I didn't want the bass to eat any adventuresome fry that sneak through the fish tank's exit; this way, the 1st pool will serve as a catch basin for any wayward fry.

Corn is Tasseling, but...

The corn is tasseling, but I don't expect good ears. The system is extremely nutrient deficient right now, since there is so little fish biomass. The system is designed to handle around 800 lbs of fish, but there's only around 10-15 lb of fish in there right now. So since the fish part is running at about 2% of capacity, and since I'm not adding fertilizer, the plant part is extremely nutrient starved. Since it takes lots and lots of nutrients to make good ears of corn, the ears probably won't develop into anything worth eating.

If you're wondering why I'm not using fertilizer, here's why: the cheap stuff is toxic to aquaponics systems, and an adequate supply of the safe stuff (Maxicrop, aka Seasol) is tremendously expensive for a system as large as mine. I've considered dumping a bunch of phosphoric acid (which would yield phosphates as it decomposed) and nitric acid (which would yield nitrates), but it would still cost a sizable amount for the quantities I'd need. Therefore, I'm choosing to just wait until the fish can do their job. The fish are brooding now, so if there's a good hatch and good survival, the tank should be up to capacity in 4-6 months.

Tilapia are brooding

The blue-colored tilapia you see here are females with mouths full of eggs/fry. The mums should spit out the fry in a couple of weeks.

If I had panned around, you'd have seen some algae building up on the pvc and walls (you can actually see a little bit of green on the pvc in the vid). The only reason there's any algae to see is because the females have stopped feeding while they brood. Before they started brooding, the tilapia kept the pvc bone-white and the water sparkling (they LOVE algae, consuming it both by filtering the water and by nibbling on underwater surfaces on which it grows).

The males are significantly longer and are white with blue dorsal fins.  This was surprising to me, since males of most animal species are usually the showy/colorful sex and the females are usually duller and less colored.  Regardless, these white males constantly defend their nests (clean swept patches on the bottom) and try to attract romance (darting up to the school of females and 'flashing' in an attempt to get a lady to follow).  You can see one of them flash near the top of the screen at the 20-second mark in the video below, and another at the 34-second mark.

Most of these tilapia are probably 7-9" long right now.  They were only 1" long when they arrived about 3 months ago (June 2nd).

Aquaponics Corn update

The Honey & Cream sweet corn in the high tunnel aquaponics system is getting bigger, as you can see here:

I had wondered whether we'd see a decrease in plant health and robustness along the flow of the bed as the water lost oxygen along its route. I think we're seeing a slight hint of that effect: the corn towards the beginning is bigger and yellower, while the corn towards the end is smaller and greener. I think what's happening is this: due to decreasing oxygen levels, the corn towards the beginning is growing faster than the corn toward the end; and since the grow bed is new and lacking in sufficient nutrient buildup, the faster-growing corn is yellower since, due to nutrient deficiencies, its rate of growth is outstripping the rate at which it can manufacture chlorophyll.

It's interesting to note that the system is so nutrient starved (due to having so few fish in it so far) that the aquaponics corn is lagging behind the outdoor sample of the same variety that was planted at the same time:

The corn I grew in my small aquaponics system last year grew about 50% faster than the corn I grew alongside it in the dirt garden, and I have little doubt that the current larger system will produce similar results once it gets better established.

Composting Worms for Aquaponics

Most aquaponics systems benefit significantly from being stocked with composting worms. When the worms eat the fish waste and vegetative matter in your grow bed, their digestive process unlocks a tremendous amount of nutrients that would not otherwise have become available for the plants. This results in significantly faster, lusher, and more productive plant growth. On top of this, the activities of the worms help to keep the growbed flowing smoothly by reducing the risk of clogging.

I stocked my high tunnel aquaponics system with red wrigglers (eisenia fetida), which are especially well suited for media-based aquaponics grow beds (gravel, clay hydroton, etc) due to their small size and big appetites.  I don't raise and sell composting worms, but you can order them online from sources like this:

Composting Redworms (Eisenia fetida) - 1 lb - $26.50

Retail Price: $36.50

You Save: $10.00

from: CompostMania

Composting Redworms (Eisenia fetida) - 2 lbs - $49.50

Retail Price: $59.50

You Save: $10.00

from: CompostMania

Composting Redworms (Eisenia fetida) - 5 lbs - $99.00

Retail Price: $109.00

You Save: $10.00

from: CompostMania

Greenhouses and High Tunnels

High tunnels are an inexpensive type of greenhouse that are well-suited for aquaponics. I use a high tunnel to protect my aquaponics system from the elements and to allow year-round growth, even when outdoor temperatures are below freezing.

If you're interested in a greenhouse or high tunnel, I'd suggest getting a kit from Growers Supply. I was referred to them by the manager of a local nursery and have been pleased with them.

Click on the picture below to check out their extensive selection of greenhouses, high tunnels, and supplies. Happy hunting!

Aquaponic Corn

The corn is coming up:

Some wily critters tore into a sack of wheat berries, so I put the spillage in a bucket with some water.  Hopefully the wheat will soften up enough (and be tasty enough) that the tilapia will eat it.

Compost pile:

Getting a bit portly:

Here's the only vegetation I left in the greenhouse when I planted the corn.  The greener stuff in the bottom left is basil, lightly cooked.  The sprawling tomato plant actually originated as a limb that broke off of one of the old monster plants.  I stuck the limb in the ground to see if it would take root, and it did.  It has flowered quite a bit, but with the temps getting so hot (108F outside, and hotter than that in the greenhouse), it's having trouble setting any fruit. 

Testing My Aquaponics System with Sweet Corn

I've just cleaned out the high tunnel and planted the entire grow bed with a sweet corn variety called "Merit."  I don't expect the corn to do very well for a number of reasons: extreme high temps during the days, high humidity, and low (but exponentially growing) levels of fish poo to name a few.  That said, I'll still be able to learn some valuable info by seeing how the corn grows relative to itself; that is, whether there is uniform growth throughout the grow bed.

Hopefully we'll see uniform growth, but disparities would not be unexpected.  Oxygen levels could be a culprit of such disparities: since I only oxygenate the water while it is in the fish tank, that means that the water steadily loses oxygen as it passes through the grow bed.  If plants don't get enough oxygen to their roots, their growth will be stunted (or they'll outright die).  If oxygen levels drop below desired levels along the water's path through the grow bed, it will be visually obvious: the plants will be continually smaller along the path.

Nutrient levels also diminish along the way as water passes through the grow bed, so another possible cause of any variations in the growth pattern may be attributable to a lack of nutrients (i.e. insufficient fish waste).

If I don't see any systemic variations, then that means the nutrient and oxygen levels are remaining sufficiently high throughout the water's path through the grow bed.  If the plants get smaller along the water's path, though, then the system is suffering from insufficient oxygen, insufficient nutrients, or both.

Here's the mighty corn patch in its current form:

And here are some gratuitous pics from the fish half of the aquaponics system:

The outside garden is full of sprouting corn.  The section in the first pic is just double rows of corn; the section in the 2nd pic features watermelon and cantaloupe plants in between the double rows of corn.  I'm hoping the combo strategy will be successful since watermelon plants send their roots much deeper than corn plants (thereby allowing the watermelon and corn to pull their water and nutrients from different strata).  We'll see.

 

Sad Day in Aquaponicsville

I put one of the tilapia in a new outdoor aquaponics system yesterday, and unfortunately I was dumb on two fronts: the system was extremely full of water (within 2-3" of the lip) and uncovered.  I found the fish dead and semi-dry on the ground about 12 hours later.  I tried to revive it for about 20 minutes, but it was too far gone and never responded.

species:  blue tilapia
weight:  32 grams (1 1/8 oz)
length:  4.5"
age:  probably 9 or 10 weeks (had it for 7.5 weeks)

Tilapia Grow Somewhat Quickly in a Good Environment...

The tilapia are now around 4" long (individual variance of +/- a half inch). My best guess is that they have tripled in length since my last post less than a month ago, with their mass increasing by a factor of 10. 

The first two pics are just with the camera; I shot the last two with my polarized sunglasses covering the lens:

Here's the view from the doorway.  I'm in the process of clearing out the tomatoes and cucumbers from the left-hand side for a fresh planting.  The lettuce on the right-hand side is only there out of curiosity.  The shrub-looking things behind the lettuce are eggplants.

Tilapia update

The tilapia seem to have doubled in mass again:

Tilapia fry have nearly doubled in size

Pic of the baby tilapia taken yesterday (6/13):



Pic of the same fish taken 11 days earlier (6/2):

Tilapia fry in their new aquaponics nursery

Outdoor lettuce is looking good!

This outdoor lettuce isn't part of my recirculating aquaponics system, but I occasionally fertilize it with water from the fish tank, so I'll indulge it for a post.




Mixed varieties of leaf lettuce:




A row of Black-Seeded Simpson lettuce:



An Oak Leaf lettuce plant:


Buttercrunch is my favorite. It forms a loose head that resembles a giant dark green rose (here's a better pic from an earlier post):



Here's some Outredgeous Romaine:


This is some type of red Bibb lettuce. I'm not sure what its name is, but tonight I think I'll call it dinner:


A patch along the back end of the tunnel:


And some spinach for good measure: