01 Jun What can you tell me about pruning greenhouse tomatoes?
Answer: The type of tomato plant that you are producing can dictate the need for pruning. Determinate varieties often are early and have a short but concentrated production season. These plants are staked or caged but are not adapted to trellising. Determinate varieties are not heavily pruned, regardless of the support system, because most of the fruit is produced on the branches.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. Johnny’s Selected Seeds has a great video on pruning tomatoes that distinctly shows which shoots to prune and how to leave two leaders on the tomato plant. It is available atwww.johnnyseeds.com/t-videotomatopruning.aspx?source=GrowingforMarket0710.For more information, consult the ATTRA publication Organic Tomato Production. This publication focuses on the specific challenges of tomato production, including site selection (soil and climate), variety selection, sources of organic seeds and organic annual transplants, organic grafting, planting and training/staking arrangements, soil fertility and fertilization, crop rotation, and pest (insect, disease, and weed) management. Harvest and yield/productivity are closely related to marketing possibilities. While market conditions are extremely region-specific, this publication also addresses a few general principles on marketing and economics of organic tomatoes. It is available at https://attra.ncat.org/attra-pub/summaries/summary.php?pub=33.