WRENTHAM, Mass. -- Bales of hay and silt fences used to control erosion at some construction sites may be doing more harm than good, according to a landscape expert.

Hay Bales Go Green

NewsCenter 5's David Brown reported that bales of hay at a 12-acre construction site in Wrentham are set up to prevent runoff and reduce pollution to nearby water sources.

"With the hay bales and silt fences, they could be full of invasive weed seeds. They were originally designed for stopping sediment," said John Engwer, of Groundscape Express. "As you drive down the road five years later, they are still in place."

In fact, the bales should have been removed long ago. Instead, they sit and rot and seeds that were lodged in the hay have sprouted weeds not native to the area.

Engwer said he has an organic solution called Filter Mitts. A truck blows compost into hemp fiber sacks, which are used instead of the bales.

The organic berm keeps runoff at bay, and the organisms in the compost can benefit the soil. The compost has been carefully cured to hold on to excess water runoff while supplying the surrounding land with extra nutrients.

"Not just stops sediment, it filtrates any contaminants and cleans it," said Engwer. "The hay bale has no benefit for the cleaning water."

Not only does the traditional erosion control aid in the spreading of invasive weeds and plants, but it also acts as a barrier for wildlife. The organic solution does not.

"Animals can't get through the silt fences or the hay bales. They can't climb over them. With the Filter Mitt, they can actually walk over them," Engwer said.