Links will also be with Love the Plot You’ve Got, schools and horticulture colleges.
The Sun Flower Square will focus on front gardens as a living seed catalogue with a schools' home grown display.
The plan is for the display to bring together growers and retailers.
HTA chief executive Carol Paris said: "This represents a wonderful opportunity for the industry to come together and showcase its work at such a high profile event."
The RHS will announce if the application has been successful in mid-November.
Some 10 seed companies plus schools, colleges and GCA members are already committed to the project. The stand is set to be 8m by 8m.
Seabrook, who is 80 on 2 November, said: "I would be nice for 80 companies from the trade to represent one of each of my years."