Why people who follow Jainism don't eat root vegetables (Potato, Onion, Garlic etc)

I think this is the perfect answer for this question.

https://www.quora.com/Why-do-Jains-not-eat-onion-and-garlic

Also, please refer to this article for 'Jain vegetarianism'.

https://en.wikipedia.org/wiki/Jain_vegetarianism