No Heaters and the Fish are Still Alive

A picture of one of my bluegills from last summer

One of the most fundamental tenets of medical ethics is primum non nocere, or "first, do no harm." In the practice of medicine, this means it may be better to do nothing rather than commit an act that risks causing more harm than good. When it comes to aquaponics, Ive taken this advice to heart when it comes to feeding my fish and heating their environment.

I covered the greenhouse in early January but I didnt get around to connecting my rocket mass heater and solar heaters. Last year I was worried about either exhaust leaks or melting things in the case of the rocket mass heater or pumping cold air into the greenhouse during overcast days in the case of the solar heater. I eventually figured out how to overcome these difficulties. But 24 hours isnt enough time to do everything I want to accomplish in a day. As a result, my lovely heaters havent been in use this winter. When I say "No Heaters and the Fish are Still Alive," I mean there has been no supplemental heat at all this entire winter.

And yet the fish (goldfish, bluegill) have survived.

I had a scare while we were fixing dinner for Chinese New Year. My son-in-law mentioned the green onions in the dishes were from the garden. Since I hadnt been to the garden that day, I asked about my goldfish. The goldfish live in the sump tank, and the sump tank water levels had gotten low that week.

He said, "I didnt see any goldfish. But the water is only a quarter inch deep in that tank."

I was sure the fish were dead. But when I got a chance to go out and inspect, I saw that the sump tank, though nearly empty, still had a couple of inches in the bottom. The pump is elevated on a pad so it stops pumping water when the level drops that low. The three goldfish were still in there, alive and well though cold.

In the same vein, Ive worried about the bluegill. During cold snaps, Ive gone for days and even weeks without visiting the greenhouse, much less feeding the fish. Whenever that happens, I begin to worry that Ive got a tank full of cold water filled with dead fish. Im just hard-wired to think an animal has to eat every day. Intellectually I know its actually more harmful to feed fish when the water is nearly freezing. But the anxiety monster grows until I get a chance to go out and lift the lid of the tank. So far Ive not had a single bluegill die.

I did lose my single surviving minnow, a fathead minnow or toughie (tuffie) as they are sometimes called. However, these minnows are only supposed to have a lifespan of 14 months. Its rather astounding that this solitary fish had managed to survive for at least 22 months after I bought him. If I thought my toughie had died of disease, I would have disposed of him outside the garden. Old age, however, isnt a communicable disease.Since the water was near freezing, I slid him into the bluegill tank, where one of the fish made a quick meal of my toughies mortal remains.

Though nighttime temperatures will continue to drop below freezing, the weather should warm from here on out, on average. More importantly, the days will become increasingly warm, and the longer days will begin pumping heat energy into the greenhouse, to the point that I may have to start lifting the side walls by April or May.


Average highs, lows, and rainfall

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Square Foot Gardening with Aquaponics

A Grow Bed with a Grid

I like the idea of square foot gardening - marking your growing space into square patches that are each about one square foot in area. But since I have these oval rubbermaid tanks, I hadnt wrapped my mind around how to do the marks.

But this past February I decided to pay attention and figure something out. I took some thin rope and black binder clips. The binder clips can be the small ones that hold 3/8-inch of paper. This allows them to grab onto the edge of the lip of the rim securely. Then the thin rope is tied between the handles of the binder clips on opposite sides of the grow bed.

When I initially created the grid, the rope was slack. Heres where the rounded edges come in handy. I moved one of the binder clips for each pair around the lip so the distance between the two clips was smaller. I re-tied the rope between the clips, then slid the clip back into position. This made the rope taught.

Once I was done, I broadcast seeded the squares, as well as planting my floating raft. I also added seed to bare patches in my two grow beds that still had plants that had survived the winter. Heres the map I drew for myself.



I planted seeds on 2/16, and a month later the bok choy, turnips, and radishes have germinated. Im starting to see hints of cabbage and leek, and my carrots and beets are still AWOL. Im sure they would have germinated more quickly inside, but direct seeding is much easier. And even though most of the nights since February 16th have dipped below freezing, the temperature of the water in the fish tanks has held steady at 40-50 degrees, as measured by my "through the cover" meat thermometer.


My tank temperature was still 38 degrees on February 23rd, even though night-time temperatures had dipped well below freezing for six nights in a row leading up to this picture.

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