Gardman announced its Stock Availability Guarantee at Glee 2015 after issues with stocks led to air lifts last year.
Gardman said pre-season orders were also running "significantly" ahead compared to early March 2015.
Gardman chief executive officer Pete Utting said a new forecasting system will enable Gardman to respond even better to changing seasonal demands:
"This will not only help us to manage stock levels but, will also be of enormous benefit to our customers by anticipating their demand and ensuring we continue to support them with a high level of availability. It’s the latest example of our continued commitment to ensure our customer service levels are the best in the industry."
Business development director James Brindle added: "They are telling us that customers are responding extremely well to our new stocking strategy and evidence of this is clear with the unprecedented level of orders they’re placing with us across so many of our categories."