you hit the nail on the head with that. Snake oil salesmen. People seem to want to pay to be told something you can read in a book. Its taking money off fools.

Buy a book and read it. This one:

http://www.amazon.co.uk/Grow-Your-Own-Vegetables-Larkcom/dp/...

This is the only gardening book i own. People keep buying me new trendy ones etc endorsed by celebrity morons but they usually end up being re-gifted.

This is good for anywhere in the world as well even though it primarily targets northern hemisphere.

Decades of advice, concisely compiled. Its the SICP of gardening.