Nominees include big players Wyevale, Dobbies and Focus.
The latest garden centres to book seats include Glendoick, Simpsons, Christies of Fochaber, The Garden Group, Buckingham, Frosts, Grosvenor, Fairweather's, Golden Acres and Fermoys.
Suppliers and service companies that have booked seats include Mr Fothergill's Seeds, Scan-brokers International, Vital Earth and Scotts Miracle-Gro.
Sponsors are HTA, Westland, Quinton Edwards, Greenfield Software and Compact & Bale.
- To book seats, email firstname.lastname@example.org or call 020 8267 4161.