America’s gardeners love tomatoes. The homegrown tomato consistently tops the vegetable popularity chart, as gardeners strive to keep plants healthy and the fruits blemish-free.
My wife, Mary, and I are no exception to the tomato growing frenzy. Each year we plant about 30 tomato plants, eating what we can and canning what we can’t, although last year’s canning lid shortage made freezing a preferred option.
The following are gardening tips for keeping tomato plants healthy, happy and productive:
- Hopefully, we all remembered to plant our tomatoes deeply, because they produce roots along the buried stem, building a larger root system capable of increased tomato production. If we didn’t, hilling soil up around the plant’s base helps compensate and makes plants less susceptible to wind whipping.
- Know which type of tomato plant you’re growing, because care can differ. Determinate varieties are more bushlike, producing fruit without extensive vines. Indeterminate varieties continue growing vines throughout the season. If you’re unsure, but know the name of your tomato cultivar, the type is usually indicated on the tag or easily researched online.
- Determinate tomato types can be grown without cages or staking, although they can be used if desired. Indeterminate varieties sprawl outward if not supported, so caging or staking is recommended.
- Tomato cages or stakes are best installed while plants are young, so developing growth can grow between cage slats, or be tied to stakes as the plants get bigger. Staking and caging help prevent foliage diseases by keeping plants off the ground, allowing increased air circulation.
- Fertilize tomato plants as they grow to maintain vigorous vines and provide nutrition for developing fruit. Water-soluble types like Miracle-Gro can be applied every two weeks, using either the all-purpose formulation or the type developed especially for tomatoes. Another option is granular well-balanced fertilizer such as 10-10-10 applied to the soil around plants, following label directions. Do not use high-nitrogen lawn-type fertilizers, which cause excessive leafy growth at the expense of fruit production.
- Removing any tomato leaves that touch the soil can help prevent soilborne disease organisms from accessing plants, reducing the likelihood of foliage blights.
- Pruning indeterminate tomato varieties can increase fruit quality and production while limiting the sprawl. Pruning involves removing side shoots, called suckers, that form in the axils where leaves meet stems. To begin pruning, locate the lowest flower cluster on the plant and the sturdy sucker immediately below it. Allow that sucker to remain, which will grow into a second vine partnered with the original. Remove all suckers above and below that point, so the plant will have only two main vines. Remove additional suckers as they form during the summer.
- Mulching around tomato plants controls weeds and conserves moisture. Apply 2 to 3 inches of straw, shredded bark, compost or dried grass clippings that haven’t been treated with lawn herbicides. Clippings from lawns that have been weed-sprayed can cause permanent damage to tomato plants.
- Avoid overhead sprinkling of tomato plants, because it can worsen foliage diseases by splashing fungi and bacteria from soil onto plants and from leaf to leaf. Water only the soil or use soaker hoses.
- Prevent leaf diseases by keeping water off foliage, staking plants and mulching soil. During periods of high humidity, vegetable disease preventative fungicides containing chlorothalonil can be applied before symptoms occur, or at the very earliest signs following label directions.
- Blossom end rot is a very common tomato disorder causing the bottom of the fruit to become sunken, brown-black and leathery. It’s caused by the plant’s inability to access available soil calcium because of fluctuating soil moisture, roots damaged by hoeing too close or soil that’s too wet or too dry. It’s worse on the first fruits of the season, and plants frequently work themselves out of the situation. To reduce the disorder, apply mulch to keep soil moisture uniform and reduce the need for close cultivation. Research on calcium sprays is inconclusive. Epsom salts are sometimes touted as a cure, but the product is definitely not recommended by university research, as it can cause magnesium imbalance.
Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at firstname.lastname@example.org.