Are harder materials such as fruit stems or the pits of fruits like dates and avocados or even popcorn kernels, able to go in the bokashi plus?
With the exception of fruit stems, some people chose to leave the other ‘harder’ items out of their Bokashi bins.
The Bokashi microbes will find easier access to the sugars and starches in the relatively softer fruit stems. This means that these items will ferment successfully, and thereby be turned into valuable soil building pre-compost. If your fruit stems are particularly firm (hard), for whatever reason, then you can simply leave the Bokashi bin to ferment for an extra few days or so. Longer ferment time is always beneficial, and is not in any way detrimental to the process. Many people opt to let their Bokashi bin sit for up to 3 weeks once it’s full, and get excellent results.
The harder items, like avacado pits, mango pits, date pits, popcorn kernels and the like, are simply too firm for microbes to penetrate. This means they will pass through your Bokashi bin relatively unchanged. If you are particularly motivated to using Bokashi (or any type of compost method for that matter) for these harder materials, then you will have success if you smash and break them down before putting them in. Smashing creates more surface area relative to the size of the material, and thereby greatly increases the speed of composting. Many people do this with bones with good success.