An easier project might be to detect when fruits or vegetables are ripe. The camera should detect color, or else it should take multiple shots through red/yellow/blue filters in order to build a color image.
The software must recognize each individual fruit or vegetable. It gauges the color and size. It sends you an alert when it is ripe to pick.
Perhaps you can program it to detect diseased or overripe condition or holes burrowed by a worm, etc.
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Or another project: Detect a bloom as it develops, and send alert when it opens.
Or another project: Detect when plants need watering. The leaves start to wilt. This might manifest as:
* color becoming pale
* drooping leaf and/or branch of plant
* rippling around the edge
Etc.