In traditional Jain food rules, potato is not allowed.

Reason in simple words:

• Potato is a root vegetable (it grows under the soil).
• When we pull out a root vegetable, we:

- Kill the whole plant. - Disturb and kill many tiny living beings (micro-organisms, small insects) in the soil.

• Jain diet is based on ahimsā (non‑violence) and minimizing harm to all living beings, so root vegetables like potato, onion, garlic, carrot, beetroot, radish, etc. are avoided. ( jainknowledge.com)

Across both Śvetāmbara and Digambara traditions, the general rule is the same:

• No meat/eggs.
• No root vegetables (including potato). ( jainknowledge.com)

Some modern Jains do eat potatoes due to habit, convenience, or weaker practice, but from the point of view of Jain dharma and ideal conduct, potato is considered not permitted.

You can read more in detail about Jain food habits here: