Portas is presenting the findings of her inspections of garden centres and DIY stores to the HTA Garden Futures conference on 12-13 October.
The star of BBC TV's Mary Queen of Shops will headline this year's HTA strategic business event, Garden Industry - Evolution or Revolution? Portas has been invited to visit and challenge "the business status quo" of several of the UK's leading garden centres.
HTA director-general David Gwyther said Portas will choose her own retailers to visit and give objective feedback to the conference. He added: "I hope her findings will be an endorsement of the garden retail market and will be helpful for keeping the independent retailer ahead of other people coming into the market, such as supermarkets."
Gwyther said he hoped Portas would find the best independent retailers as good as the best on the high street and that she will find that high street retailers could learn from garden centres. He praised the "brilliant layouts" of Barton Grange, Van Hage Peterborough, Webbs and Beckwith Emporium.
Portas reviewed Homebase in June and gave the DIY chain just three out of 10. She said it lacked service, experience and a specialism. A representative of Portas' company Yellowdoor said Portas had not yet decided who to visit.
Following her presentation, views of leading players from within the industry on key trends in future retail development will be debated, under the questioning of Horticulture Week's business and management adviser Leslie Kossoff.