Salem

How do fields look when they are ready? How can I tell? Are there some example pictures of the different stages? Would be much appreciated.

http://salemwiki.info/index.php/Agriculture

Some crops have multiple stages at which they can be harvested.
The last growth stage is usually big and bushy and notibly different from the last.

All crops that are done will give the option 'harvest' when you right click on the field provided you have the corresponding skill for planting.

Only for pumpkins there are pics, sadly. Any more info on this? Would be nice.

Cotton - visible white cotton buds
Corn - visible ears of corn
Cereal - visible bright yellow ears
Cabbage - visible bright green

Sorry don't have pics. Best thing I recommend you can do is you set a timer (Enders client) for the growth time of each crop or keep periodically checking for harvest option to familiarise yourself with the final stages.

edit: growth time

Cotton/pumpkin (baby bear) - 96 hrs
Cereal/cabbage - 72 hrs
Corn (baby) - 48hrs ?

Full-grown corn: 72 hours

Pumpkin 1st stage: 4 days
Pumpkin 3rd stage: 8 days

I am pretty sure about these numbers, but do correct me if I am mistaken.