This is the 11038th most frequent Polish word.
folią
"Folią" in English means "foil" or "plastic sheeting."
Here, 'folię' is a direct object in accusative case referring to thin plastic material used for wrapping.
Kupiliśmy nową folię do pakowania prezentów.
We bought new foil for wrapping gifts.
In this sentence, 'folią' is used in instrumental case, denoting the means by which food is protected.
Należy zabezpieczyć jedzenie folią, aby pozostało świeże.
Food should be secured with foil to keep it fresh.
'Folią' here is also in instrumental case, used to indicate the material covering the plants for protection.