The word fertilisers is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 15
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (40 words)
felsite, ferrets, ferries, ferrite, fertile, festers, fierier, filters, firelit, fissile, flirter, lefties, lifters, refiles, refires, reflies, refrets, refries, reifier, reifies, reliefs, reliers, relists, resifts, resters, restirs, retiles, retires, retries, riflers, selfies, sifters, siltier, sterile, stifler, stifles, strifes, tieless, trifler, trifles