hayseed n.

"grass mown," Old English heg (Anglian), hieg, hig (West Saxon) "grass cut or mown for fodder," from Proto-Germanic *haujam (source also of Old Norse hey, Old Frisian ha, Middle Dutch hoy, German Heu, Gothic hawi "hay"), literally "that which is cut," or "that which can be mowed" (from PIE *kau- "to hew, strike;" source also of Old English heawan "to cut;" see hew).

Slang phrase hit the hay (pre-1880) was originally "to sleep in a barn;" hay in the general figurative sense of "bedding" is from 1903; roll in the hay (n.) is from 1941.

Middle English sēd, from Old English sēd (Anglian), sæd (West Saxon), "that which may be sown; an individual grain of seed," from Proto-Germanic *sediz "seed" (source also of Old Norse sað, Old Saxon sad, Old Frisian sed, Middle Dutch saet, Old High German sat, German Saat). This is reconstructed to be from PIE *se-ti- "sowing," from root *sē- "to sow."

Figurative sense of "offspring, progeny, posterity," now rare or archaic except in biblical use, was in Old English; the figurative meaning "that from which anything springs, latent beginning" is by late Old English. From late 14c. as "act or time of sowing." The meaning "semen, male fecundating fluid," also now archaic or biblical, is from c. 1300. For the sporting sense (by 1924), see seed (v.).