Ansell Garden Centre, Sipson Village Garden Centre and John Train Plants will be compulsorily purchased and knocked down after transport secretary Geoff Hoon passed proposals for a third runway, a sixth terminal and 220,000 more flights a year to open in 2015.
At Ansell Garden Centre, the runway will go straight through the entrance. Co-owner Paresh Raithatha said: "It's going to be a long battle. The Government has a lot to achieve if it wants to get this through. It's not a done deal.
"There will be battles with the EU, environmentalists and human rights groups. We'll be open past 2010 at the least. But compulsory purchase will push things through."
Across the road from Ansell, John Train Plants has been growing bedding plants for 14 years. Manager Tim Cousins said: "The business will go. There will be an uproar if the runway goes ahead."
A Sipson Village Garden Centre representative said: "It will mean we will have to close down."
- See Garden Retail, out today, for more.