The latest HTA Market Update shows garden centre sales recorded by the HTA Garden Retail Monitor were eight per cent down to the end of February.
January 2013 was down 15 per cent on January 2012, and February 2013 was down one per cent on the same month last year.
January 2012 was 10 per cent up on January 2011, so in comparison with 2011 January sales were down five per cent.
The HTA said "continued wintry weather is likely to have had a huge impact" on March sales, given that March 2012 was particularly strong.
HTA director general, Carol Paris said: "It is a waiting game at the moment with garden centres looking good and ready for business. It remains to be seen how spring will play out and whether it will be the beginning of a much needed recovery in consumer garden spending.
"However, it is clear that the longer it takes for the weather to improve the smaller the window of opportunity for garden retailers to attract consumers to spend."