I do this every year. I usually pinch my lateral shoots out early when they are small but I'll let one grow to about six or seven inches long and Bobs your uncle you have a new tomato plant.
I buy one tomato plant
and then every three or four weeks I plant a cutting and I've got tomatoes
all season. And it's as easy as it looks. I even just stick the cutting
straight into the ground where I want it to grow.
Big thanks to Mr. Brown Thumb for making this video and he also has an excellent blog you might want to visit by clicking this link. Mr Brown Thumb's blog link.