Hi. I don't know if herbs effect a cycle, but I just thought I would tell you my experience since I am also irregular with my cycles. I always had a hard time pinpointing ovulation. I got pregnant with my first daughter within a month of trying and I think that was luck. My second daughter took about 6 cycles to conceive. I was getting frustated after a few months of trying and read Taking Charge of Your Fertility. I tried the ovulation test, but I don't thing they helped. But what did help was looking for signs of ovulation, such as clear discharge that changes to a thick egg white looking dis. when ovulation is very near. I didn't even know about the discharge when I got pregnant with my 1st. Taking your basal body temp. also helps. But I will say it didn't with my 2nd. I also found that although I was irregular, I was ovulating about the same week every month. My cycles were high 30's to low 40's when I was working, and went to low 30's when I became a stay at home mom. Hoped I helped a little. Good luck.

K

When you urinate on a stick from an ovulation predictor kit, it will turn color the day before you ovulate, indicating a surge in luteinizing hormone (LH). This surge is what causes your ovary to release an egg. An ovulation kit increases your chances of conceiving by enabling you to time sex to within a day of the LH surge.
A basal body temperature (BBT) chart can tell you when you have already ovulated. Your basal body temperature and cervical mucus reflect your progesterone level, which is close to zero before you ovulate and rises dramatically after ovulation. When your progesterone level rises, so does your temperature, giving you a sign that you have ovulated.
A BBT chart tells you something about when you ovulated in a particular month, but it can't tell you exactly when to have sex (or uterine insemination) that same month. You have to chart your BBT for a few months and spot a pattern in your cycle before you can use it to predict when you're most fertile. An ovulation predictor kit, on the other hand, can give you advanced warning of ovulation the first month you use it. The main drawback to the kits is that they can be expensive, running between $15 and $50 per cycle.
And also, I hope this link could help you. I hope I could help you with this information. :-)