During Chaumasa (Chaturmas), the four-month monsoon period, many Jains observe stricter dietary rules. This period is commonly dated from Devshayani Ekadashi to Kartik Ekadashi, which roughly spans July to October (sometimes into early November, depending on the lunar calendar). In this time, some communities avoid green leafy vegetables and root vegetables to minimize harm to tiny life forms, and they often keep a simpler, more sattvik diet. Practices can vary between Digambar and Shwetambar traditions. Regarding jeera (cumin) and neem specifically: neem leaves (a leafy green) are sometimes avoided as part of the leafy-vegetable restrictions, but jeera seeds are not typically listed as forbidden across all traditions; exact rules can differ by local custom or guru guidance. You should check with your local Jain community for the precise practice you follow. You can read more here and here