Council on Tuesday evening agreed to a new Light Abatement By-law for greenhouse operators. Under the rules operators will be required to close greenhouse curtains an hour before sunset until an hour before sunrise. “It’s regrettable because some of this is going to be very difficult to accomplish,” said Ontario Greenhouse Vegetable Growers Association general manager Joseph Sbrocchi. The curtains can be 90 per cent closed from 2 a.m. until 6 a.m. to help prevent a night sky glow. “The blackout curtains need to be open a smidge to allow heat and humidity out because those lights can do damage to the crops if they’re not vented,” Sbrocchi said.