38 weeks prg. 3 cm, 50% effaced. would castor oil or raspberry leaf tea make my contractions closer together? still very very far apart.

Probably not: If these things (in addition to walking, sex, primrose oil, nipple stimulation, and others that don't immediately come to mind) worked reliably then we would be using them for medical inductions. Castor oil in particular has a long tradition with the midwives but it can be messy and very uncomfortable. There is no evidence of harm and and all of these things can at least seem to work sometimes.