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Square-foot gardening not perfect

Thursday, May 24, 2018

Q. I use square-foot gardening and my tomatoes get lots of diseases. What can I do to improve my tomatoes this year?

Andrea from Youngstown

A. Square-foot gardening is good in theory, and helpful for those with small spaces. The challenge is that many plants like tomatoes do not fit into a square foot. This is especially true for heirloom tomatoes that have multiple stems. Thus, preparing for the season by understanding disease development and plant spacing will help improve tomato production in the home garden.

Disease reduction in the home vegetable garden starts with prevention. The most common diseases are fungal diseases that thrive in wet, humid environments. Improving air circulation through the plant and sunlight penetration into the canopy will reduce the amount of time the plant’s leaves are wet. Staking and caging are the most recognized methods used to do this. The key is to create an environment where the leaves of the plant dry off as quickly as possible in the morning.

The other key to success is proper watering. Plants should be watered at the ground level in the morning, or by using drip hoses/irrigation to reduce water use and keep water off the leaves. Plants should get a minimum of 1 inch of water per week.

All gardeners need to use pruning as way to shape plants. Most tomato growers sucker their plants (removing the new growth between the leaf axile and the stem). Additional pruning to reduce foliage and open the plant up to more air flow and sunlight penetration into the canopy is required. Extra care needs to be taken in not pruning too much, as tomato fruit can get sunburn. It is called sunscald. Gardeners should ensure leaves above the fruit adequately shade the fruit to prevent sunscald.

In traditional rows, tomatoes should be a full 2 feet apart if using stakes. Rows should be 3 to 4 feet apart. The Florida weave is one way to reduce the amount of tying and stakes necessary for the row. This weave technique of tying includes tying to a strong T-post at each end, then weaving the strings around plants in a figure eight pattern to hold the plants up. Strings are added as the plants grow.

If cages are used, the distance between plants increases to about 3 feet. The rows should be 4 to 5 feet apart. Instead of letting the plant grow in a crowded fashion in the center of the cage, train the stems to the outside of the cage. This will increase the airflow and sunlight penetration into the center canopy of the plant.

To learn more about tomato production, the Florida weave and more, go to http://go.osu.edu/tomatoes.

Eric Barrett is OSU Extension educator for agriculture and natural resources in Mahoning County. Call the plant and pest clinic at 330-533-5538 to submit your questions. Clinic hours are 9 a.m. to noon Mondays and Thursdays.