Mike Hogan
| Special to The Columbus Dispatch
US tomato grower talks about raising prices, less tomato types
“We have two choices: Shut our doors or raise prices” Tomato grower NatureSweet executive says about a 30-year trade agreement ending.
Mid-July is a good time to evaluate tomato plant progress and make adjustments.Prune excess foliage and remove lower leaves to improve air circulation and reduce disease.Monitor plants for pests and diseases, using cultural or insecticidal soap controls if necessary.
Tomatoes are by far the most popular crop for most vegetable gardeners in Greater Columbus, and most gardeners keenly anticipate harvesting their first ripe red, yellow or purple beauties of the season.
But what happens when tomato plants don’t seem to be setting fruit, or green tomatoes don’t seem to be ripening, or insects and disease are stressing your prized tomato plants at this point in the growing season?
Mid-July is a good time to evaluate the progress of your tomato crop and make any needed adjustments.
Tomatoes aren’t a crop that you can just plant, hope for the best and wait for your first harvest. They require a fair amount of maintenance, especially when weather conditions aren’t perfect.
Let’s take a look at some factors that sometimes limit success with growing tomatoes and what the gardener can do to address these factors.
Too much or too few nutrients
Most gardeners understand that tomatoes are relatively heavy feeders of nutrients and respond well to applications of fertilizer. Application of a starter fertilizer high in phosphorus at the time of transplanting helps tomato plants grow faster and flower sooner. Application of a complete fertilizer soon after the first cluster of flowers have set will aid in fruit development.
Continued application of high-nitrogen fertilizers is not necessary and in most cases will delay fruit set and development. Tomato plants will grow tall and bushy with the continued application of fertilizers, directing nutrients to vegetative growth at the expense of fruit set and development.
Proper watering
Tomatoes are one crop that benefits from maintaining an even amount of soil moisture. Avoid letting the soil dry out to the point that plants are wilting and then soaking the soil. Constant intermittent and sometimes torrential rainfall downpours in the spring and early summer have certainly made maintaining an even soil moisture challenging.
Tomato plants require an inch of water per week, so if the showers pass by your garden, be sure to irrigate the soil slowly and deeply, soaking the soil. Light watering can cause shallow root development, increase the plant’s exposure to hot weather and drought stress and reduce fruit quality.
Avoid the use of overhead sprinklers to irrigate tomato plants as wet foliage is more prone to develop leaf diseases. Additionally, soil splashed up on the lower leaves of tomato plants can contain disease spores. The use of a soaker hose or some other type of trickle irrigation system is the most efficient and effective way to provide soil moisture in the garden.
Supporting tomato plants
Tomato plants supported by stakes, cages or some type of trellising system tend to be more productive, less prone to disease development and produce higher-quality fruits than unsupported plants. Tomatoes on supported plants are also easier to harvest and fewer fruits will be lost to rot due to lying on the ground.
Providing support for tomato plants is best achieved when supports are added soon after transplanting. Adding support for larger plants at this point of the season is challenging and is likely best-achieved by using some type of trellis, such as a sturdy woven-wire fence.
Place the fencing immediately behind tomato plants and slowly train them by attaching the main stem to the fencing with flexible ties. Resist tying stems to the fencing too tightly or closely as doing this can snap stems.
Pruning excess foliage
After the first flower buds open on tomatoes, the plants begin to produce suckers, or extra stems containing foliage that is not needed. Tomato plants produce main stems and main leaf branches, which is where the fruit develops. Suckers grow in the intersection of the main stem and the main stem branches.
Removing suckers allows for greater airflow, which will reduce the chance of leaf diseases infecting the plant. Pruning also allows for more nutrients to be directed to fruit growth as opposed to growth of foliage. The tomatoes on a pruned plant tend to be larger and often ripen earlier.
Removing the leaves on tomato plants closest to the soil can be an effective way to reduce blight diseases, especially once they get started on a plant. This may be especially important in the summer as weather conditions have been nearly perfect for the development of blight diseases.
Dispose of diseased leaves in household trash; don’t leave them on the ground or add them to the compost pile.
Scout for plant health
As the growing season progresses, the potential for damage from insects, disease and abiotic factors tend to increase. Take time to inspect tomato plants for signs of insect presence or damage in order to determine if some action is warranted.
Synthetic pesticides should only be applied as a rescue treatment when insect populations are high enough to cause significant damage to the plant or fruit.
Cultural control methods such as hand removal of hornworms or Colorado potato beetles is an effective control option for some insects, and the use of insecticidal soaps are an effective control alternative to the use of synthetic insecticides, which kill beneficial insects as well as harmful ones.
Mike Hogan is Extension Educator, Agriculture and Natural Resources and associate professor with Ohio State University Extension.
hogan.1@osu.edu