I am interested in studying for the RHS Level 2 Certificate in Horticulture,
there does not seem to be a level 1.

This is intended to be studied either at college or by correspondence
course. Both options are a long way beyond my budget. I have learned from
my present profession, IT that self study is an economical and viable
option, however I can not find any self study guides available.

Can anyone who have obtained this certification through self study advise
how they did this? For financial reasons I can not purchase a large
quantity of books but can make use of online resources and free e-books etc.

Thanks