Picking fruit is a valid occupation and one that is not limited by post-incarceration rules like not being a stockbroker after committing securities fraud or not being a childcare worker after pedophilia. While many agriculture jobs provide on the job rather than classroom training, there are skills to be acquired that can enhance productivity and value.
My point was that fruit picking, in contrast to many other potential professional activities, is not something that is likely to help an inmate build a post-release career.
When you apply for a job as a fruit picker, the employer is not going to reject those candidates who lack former experience.
Not really, it's a seasonal job (at least in Germany, but are there climates where plants bear fruit year round?) that doesn't pay enough through the season to sustain you through the entire year.