You patiently waited until the danger of frost had passed to plant your tomatoes. And you installed a sturdy support system in anticipation of healthy, robust plants. But there are still some things you can do to ensure the harvest of your dreams.
If you’ve had your soil tested, you’ll know exactly what to feed your tomatoes to help them grow healthy and strong. If not, you can choose a fertilizer specifically made for tomatoes and apply it according to package directions.
How much and how often to water will depend on the weather and type of soil you have. A lighter, sandy soil will require more frequent watering than a heavier, clay soil. If you chose to grow your tomatoes in containers rather than in the ground, you’ll need to water more often.
While problems are less likely to happen in healthy plants, you may not be able to prevent them all. Quick action may save your harvest.
The most infamous pest you may discover is the tomato hornworm. If you spot a large, patterned green caterpillar with a rather fierce looking “horn” on its tail end, you’ll want to pick it off and destroy it. The tomato hornworm will strip the leaves and damage fruit.
However, if it has small white pellets attached to its body, leave it be. Those eggs are from a parasitic wasp that will soon devour the tomato hornworm and go on to help control their presence in your garden.
If you notice a rotten looking spot on the bottom of one or more tomatoes, it’s likely a case of blossom end rot. This is caused by a calcium deficiency in the fruit and can occur even if there is no calcium deficiency in the soil. It’s usually the result of poor watering that prevents calcium from being distributed throughout the plant.
If you discover blossom end rot, remove any damaged fruit and be sure to use good watering practices going forward. If you haven’t done so, consider getting your soil tested to confirm there is no calcium deficiency in the soil. For information on soil testing, see the University of Vermont (UVM) Agricultural and Environmental Testing Lab’s website (https://pss.uvm.edu/ag_testing).
Another problem you may encounter is early blight, a fungal disease that can overwinter in the soil and appear when conditions are warm and wet. Spots appear on lower leaves first. It can spread through leaves touching the soil, soil splashed onto leaves or contact.
To aid in prevention of early blight, cover the soil with a layer of mulch to prevent contact, watering from the base of the plant (soaker hoses or careful hand watering) to avoid splashing. Preventative measures also include allowing plenty of space between plants and pruning excess foliage to increase air circulation.
If early blight is detected, remove infected leaves and dispose of them away from the garden. Be sure to wash your hands and sanitize any tools used before coming in contact with other plants.
If you’re very unlucky, you may find late blight on your tomato plants. It spreads by wind or contact, with spots appearing on upper leaves first. Unfortunately, there’s no treatment for late blight. The entire infected plant should be removed and disposed of in a plastic bag in the trash. Do not place diseased plant material in your compost.
For more information on tomato problems you may encounter, check out this UVM fact sheet at https://go.uvm.edu/tomato.
If you feed and water your tomato plants as needed, and catch any pests or problems early on, you can be rewarded with a crop of tasty and very satisfying tomatoes.
by Deborah J. Benoit, Extension Master Gardener, UVM
Header photo: The tomato hornworm, a destructive garden pest, can strip the leaves and damage the fruit of tomatoes. Photo courtesy of Whitney Cranshaw/Colorado State University/bugwood.org