The ovulation kits would be your best bet, as the calendars and apps are basically just telling you when you're most likely to ovulate based on your cycle length. But, if you don't really want to do the tests, I would just go start trying a few days before the ovulation date on the first app, and continue a day or two past the ovulation date on the second app. Also keep an eye out for stretchy, clear cervical mucus (looks like eggwhite). That's fertile cervical mucus and tells you you're getting closer to ovulation. Best of luck!