Nine gardens with full sponsorship have already been proposed for 2011, two months before initial selection in August.
Speaking at Gardener's World Live, Bennett said: "The overall atmosphere is so much more upbeat this year. We picked up the first sign of it at Cardiff, which did better than for many years, and the same thing happened at Malvern."
He added: "The most significant indicator is that we already have a lot of show gardens lined up for Chelsea - we now have more fully sponsored gardens at this point than I can ever remember having before."
Chelsea show garden numbers dropped dramatically between 2008 and 2009, from 22 to 14. The space was taken up by more small gardens, but Bennett said he expected the proportions to change with more show gardens returning next year.
Numerous foreign tourist boards are among the sponsors already expressing an interest. Monaco and Australia have both already submitted entries and Bennett said he was in discussions with two Gulf states.
"We have got strong interest from China and Taiwan," he added. "But whether it's for big exhibits in the marquee or gardens, we don't know yet. Chelsea has a wonderful promotional strength to it so we like these sorts of gardens."
Beyond Chelsea, Bennett said exhibitors were reporting better show sales, which was reflected in RHS ticket sales, with Chelsea selling out early and Cardiff quadrupling its 2008 numbers.
He added: "It may be something to do with the weather, which has been good at all the shows so far, but spirits are definitely more buoyant this year."
But Horticultural Exhibitors Association chairman Kelvin Harbutt warned that it may be premature to declare the season a runaway success, pointing out that the picture was not so rosy for everyone.
"Yes, some people did well, but there are quite a few who are down on previous years," he noted. "Those who have a good position in the marquees are doing well but not all positions are equal."
Hardy's Cottage Garden Plants owner Rosie Hardy added: "Sales were definitely reasonable from our point of view. Certainly Malvern was fine and Chelsea was good, and we have received a lot of orders back from it."