I am in the process of buildiing a Hobbit Home.
Basicly a covered basement with a post and beam roof, covered in dirt.
My question for everyone, is this....
Is there a spice or a food item, when ground up - will deter ants and or chewing insects ?
My line of thought is, I when I am layering on the different layers of roofing material and waterproofing, would it stop or deter chewing insects, if (as an example) I put in a heavy sprinkling of cyan pepper under the last layer of water proofing membrane - would it stop the little critters ?
What about other powerfull spices? Garlic powder ? The space in between the layers is supposed to be a dry and stable environment, so it would not wash away...
Daves Hobbit Home Build progress
I remember reading somewhere that borax could act to repel ants. I used some of this in my own hobbit hole art studio for basically the same reasons you are thinking. Did it work? Hard to say. I probably could have used more. I was sprinkling some in the straw bales I was then wrapping in plastic and burying for insulation. I've still had ants inside. In fact a couple times over the years I've had swarms of the flying male drones coming out inside! On the other hand as far as I can tell the buried straw bale insulation has not gotten wet and decomposed. I also haven't had any issues with leaks and it's been over 10 years now.
The idea of DE in a dry section between layers of plastic sounds like a good one to me. I recently used it in my house for ants that were invading the fridge! I tried this in the past without much success, but I don't think I was using enough of it. This time I've made a small berm of the stuff completely encircling the fridge. It looks odd, but stopped the ant infestation pretty much immediately. I remember when I bought my bag it wasn't that much more to jump up to the 50lb bag size, so this is what I got. I now have plenty of it to be able to use generously. If you used it on your Hobbit Home I'd use generous quantities too.
I have ants every spring that like to come in a visit my apartment. Mine is a basement apt. and the ground comes up about half way up the walls, so I always have fun little creatures that like to come inside. I use peppermint essensial oli. in a little vinegar and water. Sometimes I add a little castile soap or some oregano or lavender oil. I do have to reuse this every few days. but then I have not really tried to completely get rid of them. You could try planting mint and other herbs. I really only have trouble in the spring when they are wanting to expand. Once I convince them this is not the place to do so the rest of the year is not bad.
I've had problems with ants many times, but this year a species of ginormous black ant moved into my kitchen. They were so big I could hear them talking and I'm still worried I may have to claim them on my taxes.
Every other time, my homemade version of Terro ant bait worked well (9 parts corn syrup mixed with 1 part boric acid). Ants come in droves to gobble it up, take it back to the colony, and die. Other ants that handle or eat the dead also die. The only 2 drawbacks are that I have to use the bait outside and it must be protected from rain; also, it leaves behind prime real estate for a new colony. But this year it didn't work!
I tried a cayenne pepper spray; pepper gassed myself, kitchen inhabitable for hours, and left behind pissed off ants. (However, a strong cayenne infusion, piping hot and poured down the entrance to the colony ensures no ants there EVER again.)
I finally figured out why nothing was working. These ants had extremely hard and thick exoskeletons. DT to the rescue and success!
But I'm disappointed I didn't end up with an excuse to buy a flamethrower.