Here’s the part where most people get scared. You can remove up to one-third of the plant’s foliage without stressing it out. Really. I’ve done it, and the tomato didn’t file a complaint.
If you’re growing indeterminate tomatoes in a cage or on a trellis, keep the main leader (the central stem) and prune to just two or three main branches. Yes, it looks brutal. But your plant will reward you with larger, earlier fruit. Less bush, more blush.
The “Airflow Test”
Stand back and squint. Can you see through the plant’s canopy to the other side? If it looks like a solid green wall, you’ve failed. A healthy, pruned tomato should have dappled light reaching its inner branches, like a forest floor in a fairy tale.
How To Cut Back Stock Plants at Steven Gable blog
Another test: wave your hand through the foliage. If you feel resistance, you’re overgrown. If you feel a gentle breeze, you’re golden. If you feel nothing because you cut it all off, you probably need therapy—and a new plant.
