Backyard Aquaponics
A place to discuss aquaponics

First winter with a greenhouse needing ideas for heaters...The Cheaper the better!!!

Good luck. Do your research there is lots of discussion on the forum on this topic. Search function is your friend.

Switch to cold water fish species

If you use native fish you just need to keep the water from freezing and if you are not high density stocking even a thin sheet on the top of the tank for a few days wont be a big deal. The more water the better for stabilizing temps and storing suns heat.

If you end up needing to add heat to keep from freezing, i would use a 1kw stock tank heater with a thermometer to regulate the the on/off.

Trout?

in arkansas i would suggest native sunfish or catfish. They are also fine with the summers.

yes I started with channel cat just for that reason.but i'm worried more about the plants and keeping them from freezing.I have been looking into a couple of solar options though

cold weather plants should do fine. The greenhouse will keep the frost/ice off of them and in my experience that is the most damaging part of cold weather.

Check out rocket mass heaters. It's another project but can be done really affordably and provide an efficient source of heat for your greenhouse