Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sătīvus, a, um, adj. [1. sero], that is sown or planted (opp. agrestis, silvestris, etc., that grows wild; very rare), Varr. ap. Gell. 17, 3, 4: morus, Plin. 24, 13, 73, § 120: corna, id. 32, 2, 11, § 22.
Neutr. plur.: sativa (opp. silvestria), Plin. 19, 12, 60, § 185.