Tomatoes - To Prune or not to Prune?

Sungold Cherry tomatoes have been popular in the Garden these last several years.  For pruning, when considering yield or disease experiences, check out the following forum: 'Sungold' and 'Sweet 100' -- do you let them grow crazy?  With regard to Sungold, it is interesting to note what one forum member writes: "I will admit that I stopped growing Sungold in favor of SunSugar because the later crack far less after picked."  If SunSugar is as tasty as Sungold, members may wish to try this variety next year.

ATTRA weighs in on pruning tomatoes, mentioning some indeterminate varieties.  This is especially pertinent for those growing the larger tomatoes. 

Indeterminate varieties continue to grow and produce leaves and flower clusters until disease, insects, cold, or lack of water and fertilizer kills the plants. Indeterminate varieties include Better Boy, Floradel, and Big Beef. Indeterminate varieties are heavily pruned when trellised, moderately pruned when staked, and lightly pruned when caged. The type (whether it is determinate or indeterminate) of tomato should be listed on the seed packet.

Pruning removes small shoots where each leaf joins the stem. Properly pruned plants produce larger and earlier fruit than non-pruned plants of the same variety. Remove shoots when they are less than four inches long to avoid injuring the plant. The larger the sucker before removal, the larger the resulting wound and the more wasted plant energy that went into the sucker. Tomato plants can be injured by pruning too late or too aggressively. The leaves will look stunted and wrinkled, and the injury will set them back a bit.

Remove a sucker by grasping it between your thumb and second finger and bending it to the side until it breaks. This is best done early in the day when plants are crisp and not wilted from the day’s sun and heat. Do not cut suckers with a knife because this is one way to spread virus diseases.

While pruning tomatoes can help with improving ripening times, it can also cause more sun scald damage to fruit that is exposed to the sun. This may not be as important in a cloudy climate, but it is a consideration for sunny locales. Being less vigilant about pruning as the plant starts to fruit might help prevent this.

If you are growing determinate varieties, pruning is not as useful as it is for the indeterminate ones.

A longer and more detailed article can be found in Fine Gardening's article by Frank Ferradino, Pruning Tomatoes.  The article goes into some detail on the various stages of pruning, including one last pruning about 30 days before first frost.