(June 19) If southern Illinois tomatoes began growing a month earlier, the state’s tomato production could increase by 2% to 5%, said Alan Walters, associate professor at Southern Illinois University, Carbondale.

To make that happen, however, the tomatoes just need about five to 10 degrees of protection from the April frost.

That’s the idea behind Walters’ tomato cover study.

Walters is in the second year of a study to help growers produce early crops at a minimal cost and a maximum profit.

His solution involves slitted polyethylene and cloth covers, which stay on the tomatoes for three to four weeks, Walters said.

With the covers, Walters said he harvested tomatoes May 31. Without the covers, Walters said, southern Illinois tomatoes are harvested in late June or in early July.

About 10 growers in southern Illinois use the covers, Walters said. Illinois tomatoes ship mainly throughout the Midwest, to cities such as St. Louis, Indianapolis and Chicago, Walters said.

Cohen, Ill.-based DJ Brumleve Farm installed polyethylene covers for the first time in 2006, said Dan Brumleve, owner. After planting tomatoes under the polyethylene covers in early April, Brumleve Farm harvested them on June 5, Brumleve said.

Both types of covers offer pros and cons, Walters said. The cloth covers stay on the tomatoes better than the polyethylene covers, which have a higher chance of blowing away, he said.

The cloth covers also provide a more consistent temperature than the polyethylene, which allows air to reach the tomatoes, Walters said.

But at about $60 for a 1,000-foot long by 4-foot wide roll, the polyethylene covers are more affordable, Walters said.

A 1,000-foot long by 5-foot wide cloth cover costs about $120, Walters said.