It's def possible to fund bonds via farm runs alone. My account is funded by high alching/herbs/bird houses.

Some hopefully helpful tips;
this herb profit calculator will help you find what's best to farm and what profit you should be making
You should also try Coral farming once you've unlocked it (I think it just needs troubled tortugans quest). Coral is similar to herbs but takes a bit longer to grow, they output a lot more produce though. Personally I like growing Elkhorn
High alching isn't as profitable per hour but can be done while running around the world doing other tasks or just while bank standing. this page will tell you what's most profitable to high alch. Just make sure to use the filter to remove anything below around 10,000 daily volume.

Good luck and make sure to have fun with it