Yes, pruning heirloom tomatoes helps most varieties produce bigger fruits and stay healthier. The vines focus their energy on fewer stems and put more power into the tomatoes. You'll see faster ripening and less disease when you keep your plants trimmed.
I tested this on my own Brandywine plants a few summers back. I pruned half the row and left the others to grow wild. The pruned plants gave me fruits twice the size of the unpruned ones. They also ripened about two weeks sooner, which beat the late summer heat.
My unpruned plants turned into a tangled mess by August. The leaves stayed wet from morning dew and blight spread fast through the crowded foliage. Meanwhile the pruned plants had great airflow and stayed healthy until frost. The difference was clear by the end of that season.
For tomato sucker removal in your heirloom tomato maintenance, look for small shoots. Suckers grow in the crook between main stem and branch. If you let them go they turn into full branches that sap energy from fruit making. Pinch them off small and your plant heals fast.
For indeterminate tomato pruning you want to keep one or two main stems and remove the rest. Most heirlooms are indeterminate, which means they keep growing taller all season. Limiting the stems gives you fewer but larger tomatoes. The plant puts all its power into what remains.
Check your plants every few days for new suckers and pinch them off with your fingers. The best time is early morning when your plants are dry. Wet leaves can spread disease from one cut to the next. Let the morning dew dry before you start working on your vines.
Don't prune determinate varieties the same way as your indeterminate types. Determinate plants set all their fruit at once and stop growing after that. Heavy pruning removes the branches that hold your tomatoes. Leave these plants alone except for removing dead or sick leaves.
Some heirlooms respond better to pruning than others. Beefsteak types like Brandywine and Mortgage Lifter give you the biggest gains from aggressive pruning. Cherry tomatoes handle light pruning but produce well even without it. Match your approach to what you're growing.
Stop removing suckers about four weeks before your first frost date. The plant needs that time to ripen the fruit already on the vine. Late pruning wastes energy on wounds that won't help your harvest. Let your plants finish strong at the end of the season.
Read the full article: Best Heirloom Tomato Varieties to Grow
