Fermenting pickles

If temperatures are above 90, your pickles will probably be ready in a day, two at most. Any more time is just going to cook them, like you've experienced (where they're so soft you can't remove them from the jar). In any case, you definitely want to check on your pickles at least once a day, and keep them in a shady spot so they don't get quite so warm.

Note that I have never encountered a fermented pickle recipe that calls for anything longer than a week; or, to put it another way, if your pickles take more than a week, it's not warm enough yet for fermented pickles. (And it doesn't sound like this is a problem you're likely to have.)

In addition to Marti's good advice about temperature, I've only had consistent success with Kirby cucumbers, also called (for good reasons) "pickling cucumbers". Raw Kirbies are very firm—even crispy. That lets them stand up to fermentation.

When I first tried pickling, I used slicing and English cucumbers—which left me sad and frustrated. I threw out so many batches for exactly the reason you mention: By the time they sour enough to enjoy, they were too soft to enjoy. They worked now and again, but probably less than 20% of the time.

Many pickle recipes also include one or more ingredients with tannins, which are supposed to help keep pickles firm. I normally used bay leaves. Other examples: black tea leaves, oak leaves, grape leaves,

Only Kirbies consistently give me firm pickles. As Marti mentioned, lower temperatures help too (I try for around 70 degrees); if you have a cellar, that might help. For me, using Kirbies and those cooler temps, 3-5 days yields half-sour pickles and 5-10 yields full sour.

An FAQ from the National Center for Home Food Preservation says,

Grape leaves contain a substance that inhibits the enzymes that make pickles soft. However, removing the blossom ends (the source of undesirable enzymes) will make the addition of grape leaves unnecessary.

I have had success with both of these different pieces of advice: completely removing the blossom end of the fruit and/or adding a grape leaf or two to a quart of pickles. Other tannin-rich leaves also work, like highbush cranberry and black currant.