This year nearly all of my indeterminate tomatoes have forked in the last week, they are 12 varieties and while all the same age are different heights, as is to be expected, yet all have forked nearly at the the same time. Anyone else experienced this? I wonder if there is an environmental factor at play here, other than plain old luck.
By forking I mean they have developed two main stems with a fruit truss in the fork, the stems having developed at the same time as equals to one another, not as suckers from a leaf base.