- sapodilla, {Achras sapota} L.
- saprophyte
- satsuma mandarin, {Citrus unshiu} Marc.
- saturated humidity
- saturation point of carbon dioxide
- savanna climate
- savoy cabbage, {Brassica oleracea} L. var. {bullata} DC.
- scab
- scane line
- scarlet runner bean, multiflora bean, {Phaseolus coccineus} L.
- scarlet sage, {Salvia splendens} Ker.-Gawl.
- scented tea
- scion bud
- scion, budwood
- scorch, burn
- screening
- sea-island cotton, {Gossypium barbadense} L.
- sea-land breeze
- second plowing
- secondary center of origin
- secondary infection
- secondary pollutant
- secondary source of infection
- sediments
- seed admixture
- seed bed
- seed broadcaster
- seed cleaning
- seed cotton
- seed disinfection
- seed dormancy
- seed dresser
- seed dressing
- seed fertilizer
- seed granary
- seed identification
- seed inspection
- seed longevity
- seed moisture content
- seed plumpness
- seed purification
- seed quarantine
- seed reservation
- seed specific weight
- seed storage
- seed testing
- seed uniformity
- seed vitality
- seed volume-weight, seed test weight
- seed-borne disease