Before there was HGTV, there was Bob Villa, the one man home improvement brand. The Bob Villa Website has good general information on a variety of subjects including garden care and do-it-yourself (DIY) projects.
Good places to search are:
-The Articles Library
-Lawn & Garden Articles
–The Design Tools– which can help you start to think about a project
-Ask a Question section with User Forum
DIY sites abound and that is one of the great aspects of the internet- abundant, accessible, and increasingly reliable information. Another good DIY site to try is the DIYnetwork and of course HGTV.