Unless flights resume by Tuesday, much more produce will have to be thrown away, he says.
Stephen Mbithi, chief executive of the Fresh Produce Exporters Association of Kenya, has described the situation as "disastrous".
"On average, we ship some 1,000 tonnes worth $3m (£1.9m) per day," he told Kenya's Daily Nation newspaper."
"We have handled drought, El Nino and the post-election violence, but we have not seen anything like this," Mr Mbithi said.
Horticulture recently became Kenya's greatest export earner and accounts for roughly 20% of the economy.
Exporting roses and getting beans, sugar snap peas and other vegetables onto the shelves of European supermarkets is an impressive operation, our correspondent says.
Hotels benefitting
Jane Ngige, head of the Kenya Flower Council, told the BBC's Network Africa programme that growers were trying to find local markets.
Horticulture accounts for roughly 20% of Kenya's economy
"But 3,000 tonnes of flowers is a lot of flowers," she said.
"The only flowers that are able to leave the country now are flowers going, say, to the Far East, as in Japan.
"And we are now exploring ways of getting directly to the American market via South Africa," Ms Ngige explained.
Nairobi is a major transit hub for European destinations, so the cancellation of flights is having an effect on hotels.
The head of Kenya's Tourism Federation told the BBC that four and five star hotels in Nairobi are benefitting - with occupancies between 80-90%.
And African passengers have not been spared from the travel chaos.
"I'm waiting to take a flight to Paris since Friday morning so it's a big disappointment," a business man at Nairobi airport told the BBC.
"I'm supposed to be there doing something constructive so they're now losing money and I'm losing days," he said.
The Eyjafjallajoekull 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 more than 20 European countries and weather experts say wind patterns mean the cloud is not likely to move far until later in the week.
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