In Jainism, the general principle is to avoid root vegetables and underground plant parts because digging them up can harm many small living beings. Dry ginger (sunth) is a rhizome, and dry garlic powder is also derived from underground parts, so both are typically avoided by strict Jain practice.

• Dry ginger powder: usually considered a root/rhizome; many Jains avoid it for this reason.
• Dry garlic powder: garlic is widely avoided in Jainism for spiritual/disciplinary reasons beyond just being a root.

There are small variations between Digambar and Shwetambar communities, and some households might permit very limited use for medical reasons or flavor, but the mainstream practice among both traditions is to avoid these items.

If you’d like, I can point you to pages on Jain Knowledge that discuss Jain dietary restrictions and the stance on roots.