Thank you all. WWOOF works well everywhere.
I´ve found these possible routes in Germany:
Apprenticeship: Gardener for shrubs, arboretum, orcharding, vegetables or landscape (three years in a company and school, 300-900€ salary) plus maybe a master exam afterwards
Study: horticulture, sustainable agriculture Bachelor/Master... (requires a loan without interest or mini-job)
In ger we hire guest-workers from Poland, Romania and Bulgaria for 4€ per hour. We also have lots of threshold worker around. I´ll get to know more companies to sort the good ones. Guess you need some creativity (a monopoly or product with high information asymmetry) as an entrepreneur to be able to pay your employees at least the minimum wage of 8,5€/h.
happyconcacti that´s kind of a universal rule I follow. Just find something that´s interesting and go for it. It´ll become ever more interesting and you´ll get lots of opportunities because people sense that you´re burning for this. For me the start of a new direction always has been slow but over time it breaks all boundaries like our monetary system