Several African industries have been effected by the European flight ban
Zambia's flower and vegetable industry is losing about $150,000 (£98,000) a day because of the volcanic ash over Europe that has grounded flights.
Flowers and vegetables destined for Europe have been discarded.
The BBC's Matuna Chanda in Lusaka says if the flight ban continues, it could have disastrous consequences for farm workers in Zambia.
Farm workers in Kenya have already been sent home as harvesting has stopped because of the flight ban.
Colin Rhoda, head of the Zambia Export Growers Association (Zega), told the BBC's Network Africa programme that the flight cancellations have had a "major impact" on the industry.
Zambia exports 120 to 150 tonnes of flowers and vegetables to Europe a week.
"All of that at the moment, we are having to throw away because we rely totally on air freight services out of Zambia," said Mr Rhoda.
Our correspondent says there is no indication yet how farmers in Zambia will deal with their loss of earnings.
He explains that if the flight ban continues, their jobs might be under threat.
Other African industries, such as Uganda's fish and flower export businesses, have also been affected by the grounding of planes for a sixth day.
The Eyjafjallajokull volcano system began erupting last Wednesday for the second time in a month, hurling a plume of ash 11km (seven miles) into the atmosphere.
Airspace currently remains closed, or partially closed, in several European countries, although some countries are gradually resuming flights.