Growhouse v Greenhouse

My fiancee and I are planning on starting a commercial scale aquaponics business. We have been doing research for about a year now. Learning many ins and outs and have a basic design idea on how we want our setup to work, incorporating rocket mass heaters, passive solar collection and radiant heat reclamation to name a few. The one thing I can't discern is the building type. The big issue is that we live in Maine. We have long cold winters with short days, and even in the spring and summer we have a lot of overcast days and the temps rarely break into the triple digits. Humidity is also a constant battle because it is dry in the winter and wet in the summer.

So, my question is, is it more energy efficient to heat a greenhouse year round and provide supplemental lighting for the benefit of the small amount of natural sun, or would it be better to re-purpose an existing well insulated building, add a passive and active solar system? I am leaning towards the existing structure because we would be able to use most of the space for growing as led light panels would allow for stacking grow beds allowing for greater yield. But I am really hoping that someone with experience could give some advice in this matter.

I would run some numbers on both.

Heating greenhouses is very expensive. Building well insulated greenhouses that actually retain the heat is also expensive.

Growing plants with light from other than the sun isnt cheap either. Still have heating concerns in winter too.

What exactly do you plan to grow? What is your anticipated harvest season? Yields and markets?

Shooting from the hip, I might suggest a greenhouse that you operate seasonally, say Mar-Nov. During the deep of winter I am sure you would be operating at a loss in either system.
But run the numbers, be brutally honest. See what you find. Let us know, I would be curious.

You might look into using light pipe or tubular skylights to get sunlight in through an insulated roof. it wont help much when the sun is setting at 4:30 during a Maine winter, but it would help offset electric grow lights generaly. At least thats what I'm speculating...

Ooh, you should read these books about farming and growing a lot of vegetables year-round in Maine by Eliot Coleman: http://www.fourseasonfarm.com/books . I have The Four-Season Harvest book and love it, but the other one looks good too. It explains in detail how to get vegetables 12 months of the year using a greenhouse as well as other methods, without elaborate and expensive heating systems, specifically in Maine but applicable elsewhere.

I assume you've checked out crmpi.org.

I'm not sure how much light you get in the winter. There was more than enough when I was living in Gloucester, MA. Basically, your growth times are what will be affected. Your lettuce won't be done in 5 weeks, etc. You can supplement with LEDs or CFLs.

I'd love to hear how your plans go. I'm in the test phase for my aquaponics. Getting ready to buy bigger pumps and swapping for food grade parts.

The truth is most of the known aquaponics systems in the states are either 501c3's or showcases to draw customers and students and there are only a handful of truly profitable commercial systems.

Check out http://www.brightagrotech.com/ as they are a profitable system in a cold climate.

There is a system set up in an old packing plant in Chicago. I can't remember the name, and not sure they have been running long enough to prove profitability.

Thanks for the link. I appreciate the growth estimate they provided in PDF!

Look into Chinese greenhouses. There are the best for aquaponics with their insulation properties. Also, rather than try and heat and cool the air, heat and cool the water. The water is your biggest biomass. Water very, very slowly absorbs or loses heat while the air loses heat quickly as there is no biomass. A solar water heater and heat exchange is perfect to keep the water at temperature even when it is extremely cold outside. To cool the water, trenches can be dug and geothermal lines installed that will be used with the heat exchanger to cool the water in the summer. Insulate your tanks and grow beds well so that the water continues to hold heat/cold longer.

I'm in AZ and about to start my own aquaponics so I've done a lot of research on how to accomplish a thriving system in our brutal environment. I will be building a Chinese greenhouse and using the above ideas as well. Good luck with your system.

Hi there. I'd agree with the previous post that the Chinese have a lot figured out with regard to thermal mass. However, I think Penn & Cord are better. Even better would be to replace the water in the barrels with 50 psi pressurized ammonia. You'd have to address the safety concern but it would store a ton of heat.

I've also heard that there are few, if any, profitable aquaponics farms. If they exist, they do it by selling very high-priced basil and lettuce to a high-price market like Chicago.

You also asked about the cold. That's sort-of my specialty. Feel free to get in touch via my blog or check out the forum about cold weather aquponics on the Aquaponic Source. We have some really experienced folk there that can help.

Some ideas that work well are a passive solar greenhouse like discussed above, plastic or bubble-wrap low tunnels over your beds, air sealing and insulating everything, and freezers for fish tanks.