When to water tomatoes grown in buckets?

I have 3 different tomato plants growing in buckets. I did not put any rocks or gravel in the bottom but I did drill some drainage holes. I am using miracle grow soil and I water about twice a week. I dont fully "soak" the plant with water as i know this is generally only done in the summer. I have a few tomatoes growing now on each plant but one in particular had a ton a blooms but they apparently didnt get pollenated as they are about dead. I am wondering if im watering too much or too little? Also if anyone has any growing tips I'd appreciate that as well.