that is really a decision that only you and your wife can make after discussing this with her ob and the medical clinician that is treating her depression. in most cases people can begin trying to get pregnant quite soon after a miscarriage but since i do not know any of the details of your wife's case this is not something that we should try and blindly determine on-line.
my wife had her first misscarriage after 10 weeks at the end of feb-13. when is the best time to try again for baby. we have 2 daughters. 6. 10yrs old and 5. 3yrs old. my wife is currently taking anti depression meds and psychiatrist suggest to try after 10months although meds are very safe during pregnancy wife is 32yrs old.