Last week I noticed Ohio tomatoes at local farmers markets for the first time this season. Many early tomatoes are grown in seasonal high tunnels and those of us who have field-grown tomatoes might have to wait several more weeks before our first harvest.

Between now and then, here are some tips to keep your tomatoes as healthy as possible.

• Mulch: The use of mulch when growing tomatoes is helpful for many reasons. Mulch material is placed around the plant (but away from the stem), or holes are cut in the mulch and the plant is placed into the ground through the mulch.

Mulch can help control weeds, keep soil moisture in, and help prevent diseases by preventing bare soil from splashing up on the foliage.

There are many types of mulch available including straw, newspaper, weed barrier fabric or plastic. The USDA and Clemson University reported that in field trials where tomatoes were planted with red plastic mulch, more and larger tomatoes were produced.

Each mulch type has advantages and disadvantages.

• Removing suckers: Suckers are the shoots that grow out of the leaf axil (where the stem and branch of the plant meet). These structures can grow and produce tomatoes and also produce more suckers.

The problem with allowing the sucker to grow is that the plant may become large and its resources spread thin.

Removing these structures allows the plant to put resources into fewer leaves and fruit, which will be of better quality. In addition, the removal of suckers will increase airflow and light in the canopy.

Remove by pinching or cutting the suckers off.

• Avoid blossom end rot: Blossom end rot is a physiological disorder, meaning is it caused by an environmental factor, not a disease or insect. The blossom end tissue of the tomato fruit will turn a watery color, then eventually brown, and the fruit will collapse.

The cause is a calcium issue in the plant cells. However, this doesn’t mean that there is a calcium shortage in the soil or plant. Calcium in plant cells is regulated by water, and when there is too little (drought) the plant can’t move enough calcium to the rapidly growing fruit.

The most likely issue is uneven water application. Ensuring the plant is receiving enough water during dry spells will help lessen this issue. Some varieties are more susceptible than others. Blossom end rot can also sometimes occur on the first set of fruit, regardless of how well the plants are cared for.

Calcium is taken up by the plant through the roots, and calcium sprays are not effective in preventing or “curing” blossom end rot.

• Avoid diseases: There are a multitude of diseases that affect tomatoes. Some of the most common are early blight and septoria leaf spot.

Both of these diseases are caused by fungi and tend to develop during times of extended high humidity, high temperatures and leaf wetness.

The use of mulch, weeding and removing affected leaves will help. While there are copper fungicide sprays available to homeowners, they are preventative rather than curative. Timing the application is challenging because symptoms are not seen until several days after infection.

• Staking: In addition to helping avoid disease issues, staking will provide more sun exposure, resulting in better fruit. It is much easier to stake a plant when it is small as opposed to when it has grown large. There are many options for supporting tomato plants including cages, T-posts, bamboo stakes and many other creative ideas.

• Fertilizing: As tomatoes are harvested, nutrients are being removed from the plant. It might be helpful to side-dress additional nitrogen fertilizer about 2-4 inches away from the plant after the first fruit set.

For more information on growing tomatoes see:

Jacqueline Kowalski is the Summit County agriculture and natural resources extension educator for the Ohio State University. For questions on local foods, food production or other garden-related questions, contact her at or 330-928-4769, ext. 2456. The Extension Master Gardener Volunteer Hotline is open from 9 a.m. to noon Tuesdays at 330-928-4769, option 3 or extension 2481 or 2482.