I was kind of thinking about sprinkling a little lime on top, every time I dumped in new soil.I ran into an issue when I tried reusing soil. I don’t check/monitor pH but started getting crispy leaves along with spotting that I assumed were probably due to pH. I checked the pH of the run off and it was low(I think in the mid-5’s). After reading up on it, peat when it degrades goes acidic. That being said, letting it ‘rest’ outside and flushing it may help but I can’t see how it would counter the degradation of the peat. Amending the soil may counter the drop in pH depending on which amendments you add. As subby pointed out, bugs could be a problem. As for reusing soil outside, that is a different animal. Kinda like loading in the ocean, the pH drop is probably diluted and spread throughout the garden. I also would mention that even outside, eventually soil loses its viability. That is why old time farmers did crop rotation and let fields go to fallow and also probably a big reason fruits and vegetables today have drastically lower nutrient content than even 50 years ago.
I keep my dirt out in that little greenhouse. It’s so hot in there this time of year, that I don’t think a bug could survive. It’s like getting inside of a car on a 100 degree day.