Plants were the star performers at 105 per cent up, according to GCA members.
Highfield Garden World in Gloucestershire saw March overall turnover up 14.98 per cent. The new restaurant was 64.5 per cent up, plants up 70 per cent, compost up 58 per cent, sundries up 44 per cent, gifts and cards up 38 per cent, pots and stoneware up 45 per cent, aggregates up 161 per cent and houseplants up 41 per cent.
But indoor furniture was down by 20 per cent, clothing was down 25 per cent and pets were down 11 per cent.
Stewarts Gardenlands managing director Martin Stewart said: "In March two years ago we had record sales, but March 2013 was a disaster at 35 per cent down. But this March we're 35 per cent up at one centre and 45 per cent up at the other, so it's a record March for us.
"Spring has been nicely balanced with the weather. It could be a great spring. We're well stocked but there are eight weeks to go."
Woodcote Green Garden Centre general manager Phil Barnden said March was up by 18.9 per cent. He added: "We're not selling bird care, which is probably a good thing because it means we're selling a broader range of products. We'd rather be selling plants and core gardening. There are people all round the centre rather than huddled in the warm areas."
Westland Horticulture marketing director Keith Nicholson said: "Sales out of retailers have risen sharply this year. Some retailers have experienced sales levels of more than double what they were in 2013 across many Westland products."