Latest Garden Centre Association (GCA) figures show January was 4.5% down on 2009. February was 3% down, with plants hit hardest, 28% down in the month.
GCA chief executive Gillie Westwood said: "The figures are hardly surprising. People have not been able to get out into the garden."
Even catering was hit, being 3.5% down this year. Westwood said: "For a lot of garden centres, people just couldn't get to them because of the weather."
The figures come from 46 garden centres. Clothing did well, with Wellington-boot sales booming. Sales of wild-bird food helped the pets and aquatics section.
Plants have bloomed up to five weeks later than in 2009, with record levels of snow, prolonged cold and waterlogged ground dogging gardeners from getting out and planting.
GARDEN CENTRE SALES
Year to date February
Outdoor plants 30% down 28% down
Houseplants 16% down 11% down
Seeds & bulbs 4% down 2.5% up
Sundries 8% down 10% down
Furniture & barbecue 0% 7.5% up
Pets and aquatics 7.5% up 1% up
Gifts 6% up 12% up
Hard landscaping 14% down 10% up
Food 8% up 10% up
Clothing 15% up 24% up
Catering 3.5% down 2% up
Overall 4.5% down 3% down