Winter Farming Techniques for Aquaponics – Part 2 – Winter Greenhouse Heating Plan

If you’re just joining us, we’ve been covering winter gardening techniques in aquaponics. Pt 1 here. These are old posts from 2014.

Primarily this column is to do one thing: help you learn from my mistakes, so you don’t end up making them yourself! I really want to speed up the learning curve for you. That’s why I’m bringing you my detailed experiences and the practical strategies and tactics that I’ve learned from those experiences.

Winter CSA Update

Last time we talked, we were at week 5/9 in our Community Supported Agriculture program (CSA). As of this writing (2015), we officially delivered the last box of the season on our regular Tuesday drop-off day, December 30th.

Lessons and Takeaways from this year’s winter CSA

A key component to a successful Winter CSA is a wide variety of local offerings. We teamed up with other local value added producers to make up for the lack of diversity coming off the farm this time of year. It is important to understand that while aquaponics is able to grow food all winter long, it doesn’t necessarily grow as well as say in the prime time of spring and summer. Once you understand that, you can plan for it. The network of partners you create will make up for loss of production variety due to the cold or lack of light.

Customers payed us in advance for 9 weeks worth of produce and other locally made grocery goods like artisan bread, local eggs, tea, and soaps. We also included an optional grass-fed pork add-on this season. This option offered various cuts of local pork to those who opted-in.

The variety of our weekly CSA box really excited our customers. They couldn’t wait to find out what the new type of tea, soap, bread or other offerings they would be getting that week. They also love the fact that our entire box is full of products from Connecticut. In fact, almost the entire box was sourced from our actual home-town of Glastonbury. Hows that for local!  

We also learned that it is possible to create a more robust experience than just a simple box filled with the weekly haul. Customers often asked or recipes, a list of items in next week’s box, and other things like that. Offering these simple pieces of information provides a feeling of continuity and robustness that will benefit any CSA program. Think of this information as sharable content. Maybe they’ll share it with their neighbors and spread word of your program!

We are already planning for our next session, Winter B (February and March) with these lessons in mind. Stay tuned for updates on our second winter CSA session in the future.


Back to the Winter Gardening Techniques!

Alright, enough about my CSA, on to the good stuff. Let’s talk Winter Gardening Techniques!Collapsed Greenhouse in Winter

Last time, you saw pictures of my personal greenhouse, collapsed under the first snowfall of the year. At the time, I felt that this did not bode well for the condition of this winter. Luckily, that was the only real snow we have received so far this year (I am crossing my fingers while writing this sentence hoping not to jinx myself).

It has only been winter for a few weeks now, so who knows what is to come. That is why we are implementing all of our upgrades to our major aquaponics system heating strategy now, rather than wait till its too late.

Welcome to Robb’s Farm, featuring FRESH Farm Aquaponics

Trifecta Robb's Farm AquaponicsOur large system is at Robb’s Farm. A third generation farmer, Robb Armando is no slouch when it comes to innovation and abundance. When we approached him about joining forces for an aquaponics greenhouse, he recounted when he was our age and had dozens, of hydroponic greenhouses covering his main hill. He was inspired to see a new generation of farmers with the next innovative evolution and was eager to help us construct our system on his land.

Our large aquaponics system is a Deep Water Culture (DWC) system in the style of the classic University of the Virgin Islands (UVI) system. There is a 1000 gallon fish tank and 6 DWC raft beds totaling 568 square feet of raft space and 5248 gallons of system water. This is a pretty massive body of water and it was vital we keep it warm, over the 55F threshold I mentioned last time.

Our Year 1 Winter Greenhouse Heating Plan

Last year was our first year operating aquaponics systems in the winter. As such, it was filled with exciting trials and tribulations that tested our spirit, determination and perseverance. All winter farmers will go through similar experiences to ours. I hope that our heating plan, laid out below, will help you avoid learning the hard way. We did that for you!

Our heating plan hinges on one key fact, that water releases heat slower than it warms up. That means the massive body of water (5248 gallons of system water) heats up during the day and then radiates the heat back out into the greenhouse at night, while retaining some of that heat in the water itself. This keeps the fish warm, relieves some of the heating costs and heats the plants as it radiates out of the raft beds.  

In order to maximize this process for ourselves, we use a mix of active methods (requiring some effort or ongoing expense on our part) and passive methods (requiring no effort once enacted) to heat the system.

This article covers our year 1 strategy for heating our larger system. During our first year, we were well intended but a little misguided. I want to take you through our thought process. That way you can see the evolution of the winter techniques we employ.

The two active methods for year 1 were Fish Tank Heaters and Mini Greenhouses. The two passive methods were insulation and painting the fish tank black.

We heated our 1000 gallon fish tank with 3 x 300 watt titanium fish tank heaters. This was FAR under the appropriate amount of heat for the system, which we made sure to correct this year. Nonetheless, the system easily stayed over that 55F threshold on sunny winter days due to the two passive heat sources. The black fish tank absorbs heat from the sun and passes it to the water. The mini greenhouses help to trap heat escaping from the grow beds.

I learned of the brilliant innovation of mini-greenhouses from Eliot Coleman, who is a year-round farmer in Maine! Maine is far colder than my location, so I know I can really learn a lot from him. His methods are simple,effective, and easily adaptable to Greenhouse DWC aquaponics operations of any scale. I highly suggest you check out his book.

Upgrades for Year 2

For year 2, we’ve made a number of improvements in order to maximize our winter yield and really push the boundaries on winter-farming in Connecticut. We are testing improvements like upgrading our inline heater, reinforcing our growbed structure, and adding grow lights. We also changed the material of our mini greenhouses from greenhouse plastic to cloth row cover.

We’ll cover these in more detail next time. Until then, you can always reach out to me directly at with any questions you might have. Do you have your own winter gardening experiences with any style of gardening or farming? pPease let me know on facebook or drop me a line using the chat box in the lower right corner.


Stay warm and have an abundant New Year,




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