Just in case anyone is interested, but primarily for myself when I can't remember...
Here are my thoughts on fermentation with grocery store produce... Hmm... not sure it's worth the trouble. I've tried onions, carrots, cabbage, salsa and celery and I feel pretty ho hum about it. The only thing that turned out fairly decent were the carrots that I made from large carrots. I tried fermenting the little carrots and they were a fail, but the large carrots, which I cut into sticks and coins, were okay. Not great, but okay. The onions took on a very strong flavor and were not in any way sour. The cabbage is fairly unflavorful, which I have to say is a total bummer. The salsa was complete mush. The tomatoes completely broke down and the whole thing was mush and I just could not abide the texture of that.
So, I guess the rule is to ferment with garden fresh produce. If not from my own garden, then from a farmer's market and to store the fermented items until they are used. Since I gave up my second fridge, this is a dilemma.
I totally pinched this graphic from the UCreate fb page. I hope they don't mind. It so perfectly sums up my adventures in fermentation. I learn something every single time. It perfectly sums up life, too.