So I live in Texas. My AC can’t usually keep the house below 78, which means that I need some way to artificially cool the closet/box/whatever where I plan on fermenting. Basically I’m afraid to start my first batch, because I don’t want it to get ruined because of the stupid heat down here. Any hints, suggestions, inventions?
:-\
I also live in Texas, and my A/C also has trouble staying below 78 some days. I usually put my fermenter in a fridge or freezer with a temperature controller. When they are all full, I will put the fermenter in the tub in my guest bathroom and fill it half full of cool water. I put a T-shirt over the carboy and pour water over the shirt every once in a while to keep it wet. This should cool the fermenter by 5 to 10 degrees below room temperature. You can cool even more by periodically adding ice to the bath and also by setting a fan to blow on the fermenter. If you don’t have a spare bathroom that you can dedicate to brewing, you can find a large plastic tub at your local hardware store that works as well. Make sure and put it someplace where the air will circulate around it (i.e., not in a closet).
Alternately, you can try to make something that does fine at really high temperatures, like a saison.
mark
Just get a tub at WalMart the will hold your fermentor, fill it with water and frozen bottles of water. Make sure the wort is cool before you pitch the yeast, change the water bottles before you go to work and when you get home and everything should be fine. The thermal mass of cool water and the beer will regulate the temps.
I fermented my beer in the living room at 72-74F for years before I ever heard of temp control and we all loved my beer back then. Beer is more forgiving than some people will admit. Cooler is definitely better but remember that beer has been brewed for many centuries without temp control.
This may help some good ideas from a while back. 5th one from the bottom of the link.
Beat the Heat: A Texas Tale on how to make Cool Brews when the Weather’s Hot
Note - I always smile when I see Saguaros associated with Texas - no Saguros are native plants in Texas.
no Saguros are native plants in Texas
Tumbleweeds aren’t either 
Tumbleweeds are Russian Thistle, which was brought over as a decorative plant by Russian imigrants. It spread easily here in NA.
Edit - Saguaros are native to Arizona and just a little of Southern California across the Colorado Rriver here in the USA. Saguaros are also abundant in Sonora Mexico.