Amsterdam is a great place to learn about Cannabis genetics and how it is grown. Unfortunately in the current political climate, it is not advisable for is to explain how easily Dutch Cannabis gardens are cultivated. (Do you have an older copy of the S-Guide?)
There are plenty of shops here in Amsterdam where you can see Mother Nature in full bloom.
Here's a list of places that have gardens, (or atleast one impressive "specimen" for you to gawk at!):
Most of the marijuana gardens display a variety of techniques that can be used to achieve top marijuana harvests. The latest methods and equipment are displayed with heaps of information about every product.