Backyard Aquaponics
A place to discuss aquaponics

How do any of you heat the fish in the winter in Houston, TX? The temperature in winter is usually into the 40s and sometimes gets to 20 F for a night or so. I have Mozambique tilapia. Am I better off getting some catfish?

Are there any plants that will withstand a short cold spell into the 30s or 20s?

I set up a hoop house with 6 mil plastic sheet and 3/4" PVC ribbing but it barely increases the temperature over ambient conditions.

Thanks!

Dan

What is the primary direction of your greenhouse? E=>W, N=>S?

Out in the open or close to other objects?

Any air gaps with how your plastic is attached?

Adam

My hoop house is next to my garage but it still gets plenty of sun light.

It is a single layer of plastic. There are some air gaps present as I had to kind of rush to assemble it the first day.

Would you say that the skinny side or the long side facing South?

I set my GH facing E=>W on the ends with the long side facing south. I maximized exposure to the sun and if it shinning, it heats up quickly.

Last year, my GH within a GH allowed 1500 watts of heater to keep it between 65-67 with below freezing temps. Warmer with snow on the ground covering all the perimeter.

Adam

I don't think it's cost effective to heat that much water to keep tilapia alive in AP through the winter if your temps are that cold. If you are getting down that cold you should try adding more water mass. If the greenhouse is east-west line your north wall with water barrels to give thermal mass for storing heat will keep it a little warmer, but also make it slower to warm up.

My tilapia all went in the freezer other than my ten original breeders and I saved 9 more to make more breeding colonies. They are in the house to keep them warm through the winter. If my catfish turn out good next fall I will probably switch to just catfish so I don't have to switch between seasons. The tilapia are good for eating but started becoming inactive and dying at mid to low 50s.

As for plants, winter you need to switch to cold crops. I still have tomato and pepper plants alive in my greenhouse because the coldest it has been so far is mid 40s, but the hoop house doesn't hold heat as well so it will drop down colder. Lettuce will be ok with freezing temps as long as you let it that before harvesting (so I've read anyhow). You can do like Adam mentioned and cover your beds with a second layer of plastic inside the hoop house to make it a little warmer. Watch Elliott Coleman's winter harvest video on YouTube. It's about an hour long speech he gave which gives a few ideas on what to do for winter harvesting. He says each layer of cover is like you are growing 500 miles closer to the equator. Even just row covers at night insulate plants s lot.