Participating in this challenge I found a really useful python library called eo-learn which is maintained by Sinergise who operate sentinel hub and are partly funded by the European Space Agency.

Eo-learn bridges the gap between earth observation data and the python data science and machine learning eco-system.

I wrote up a blog post on how I used eo-learn and fastai for this challenge here: https://medium.com/@sgrest/whats-growing-there-a5618a2e6933

Also my github repo is here: https://github.com/simongrest/farm-pin-crop-detection-challenge

I'm really interested to hear how everyone else approached this interesting problem!

Simon