Managing director Will Armitage said of the inaugural county cycle race: "The weather was very mixed. Our best day was Sunday which was great for when the the Tour de Yorkshire passed through the town, but the knock-on effect was that our customers went to watch the cycle race rather than visit their local garden centre."
The GCA chairman said: "Non-weather related products sold well but gardening sales were down and at this time of year that has a bigger impact on overall trading.
"It's looking like 10 to 12 per cent down on the weekend but a good 10 per cent up on the year to date."
Ferndale Garden Centre said Sheffield council had not got involved in the race and that was an advantage for sales as there was no cycling distraction in the area. It said Monday was busy, although bad weather reduced Sunday sales.