How should I prune my vine tomatoes?

Question

I've been growing my tomatoes up a 6ft trellis of nylon netting for the last couple of years, with good results. But they tend to grow out of control, eventually toppling over the trellis and breaking their branches, and parts of the branches will die out. I've never really bothered with pruning them unless a vine looks diseased or like it's dying.

I've read that I really ought to be pruning the tomatoes to the "main vine", which will result in higher fruit yields. But I'm not sure how to tell which vine is the "main" vine (or if it really matters), and which vines are just branches. After a week, both vines look rather strong. And when both vines have flowers, I'm anxious about cutting away potential produce! Will pruning it really result in higher yields?

What rules of thumb do you use for pruning your trellised tomato vines?

Answer 1

Check out this video. I use these techniques with my tomato plants with good results.

Summary:

• Leave two leaders (main stems).
• Prune all other suckers.
• Start when suckers 3" length.
• Prune every week to 10 days.
• Don't prune determinate types ("bush" tomatoes).
• Don't prune when wet to avoid spreading disease.
• 30 days before frost, prune tips of leaders to force energy into fruiting.

The video shows techniques used at Johnny's Selected Seeds farm in Maine.

Answer 2

Pinch for sure. Another trick is to let the plants grow in pots and when you transplant, bury them four inches deeper. This promotes more root growth. Stay on it. Pinch frequently until they are producing.