It is time to create a journal for your garden if you don’t have one already. I came across some sources for you, in case you haven’t found them yet: printable from your own computer.
Gives combo of information and record-keeping.
Garden Journal Printables
A Pretty and Free Download-able Journal
Example from Pinterest:
This next one will cost you something, $7.00 from Etsy shop
Garden Planning Kit
About.com, not to be outdone, has a free printable Garden Journal
Example of cover:
Example of one of the 18 different page choices:
Nice feature is the choice of printing in either color or Black and White.