Short answer:

• Peanut (singdāna/groundnut) is a seed/legume, not a root-vegetable (kand-mūl). So in many Jain households it is generally permitted.
• Still, some families or sanghs avoid peanuts—especially in Chaturmās/Paryushan—because they grow underground (more himsā while uprooting), sprout easily, and stored peanuts may have more tiny life-forms. Follow your maryādā.

When peanut chutney is considered “allowed,” it is only with these Jain rules:

• No onion/garlic or leafy add-ins on “no-green” days.
• Use clean, preferably roasted peanuts; do not use sprouted or insect-affected peanuts.
• Make fresh the same day, consume before sunset; do not keep leftovers overnight.
• No fermentation; keep it simple (salt, cumin/hing, lemon if permitted).
• During stricter vows (Paryushan, some fasts), many avoid peanuts and all elaborate chutneys altogether.

Why you heard “peanut is not allowed”:

• Different paramparās have different niyams. Some label all underground produce as better to avoid; others distinguish legumes from roots. In Jain Dharma, ahiṁsā and saiyam come first—so local gurubhakti and family maryādā take precedence.

If your sangh/family avoids peanuts, please avoid peanut chutney too. If they permit peanuts, you may take peanut chutney within the limits above.

For simple Jain food guidelines and Paryushan practices, you can refer:

• What Jains can eat
• Foods during Paryushan
• Chaturmās edible items overview