Here's a pic of this years tomatoes that I started from seeds and planted out about the end of the first week in June. I've been using black plastic for years, and it seems to help hold in the moisture and keep the soil warm. Because of the very hot summer and dry conditions, I watered every day, and yet they didn't set fruit until later when the temps got below the daily 90+ degrees. I ended up with a small crop of ripe tomatoes, and loads of green ones.
These pictures were taken in July