Plastic trash bags are good for trash, city workers say, but for grass clippings they’re a giant pain in the neck.

So, Lawrence recycling officials are trying to get homeowners to change their ways.

According to the latest numbers, 24 percent of homeowners in Lawrence who bother to bag their grass clippings use papers bags, a trash can or one of those green carts.

The remaining 76 percent use big, plastic trash bags. That’s not good, the city reasons.

“We’d really, really like to encourage people to go to what we call ‘preferred containers’ — a can, a cart or the paper bags,” said Diana Sjogren, a project manager with the city’s Waste Reduction and Recycling Division.

“In the summertime when it gets hot and the bags sit on the curb for a day or two, the sun just bakes them. So when you go to pick them up, they tear open,” said James Laier, who has driven one of the city’s trash trucks for 17 years. “It’s a mess.”

It’s time-consuming for sanitation workers to deal with the plastic bags, too. Each bag must be cut open before its contents are dumped in one of the city’s 11 trash trucks and hauled to the composting facility on East Eighth Street.

That’s a lot of bag-cutting. Each Monday, city crews log between 1,500 to 3,800 yard-waste stops, picking up anywhere from one to a dozen bags at each stop.

The crews collect so many empty plastic bags, they call a separate truck to come pick them up. Records show city crews picked up and cut open 204,000 plastic bags last year.

¢Lawrence yard waste ordinance

“It’s not a very efficient system; it’s not cost-effective, either,” said Mollie Mangerich, head of the city’s Waste Reduction and Recycling Division.

The plastic bags have to be cut open because they clog the grinder used to mix the summer’s grass clippings with fall leaves. Eventually, the mix becomes a much-desired compost, which the city gives away in the fall or early winter.

Occasionally, plastic-bag remains turn up in the compost, reducing its quality. Because they’re biodegradable, paper bags needn’t be cut open nor do they clog the grinder.

Unless more homeowners start using paper bags, Mangerich said city officials would be forced to explore the possibility of banning the use of plastic yard-waste bags.

Generally, paper bags cost between 40 cents and 50 cents apiece. Plastic bags, depending on their quality and quantity, cost about half as much.

Ninety-gallon carts are available by calling the city’s Solid Waste Division, 832-3022. The carts rent for $3 a month.

Records show the city’s yard-waste recycling efforts divert 9,000 tons — 30,000 cubic yards — of leaves and grass from the landfill.