There are thought to be 18 interested parties including venture capitalists and trade buyers in the first round of bidding. Primary Capital invested in the company in 2002. A sale is planned by Christmas 2015.
T&M Group Holdings lost £4.08m on turnover of £32.3m in the year to 30 June 2013 and a further loss of £1.82m in the year to 30 June 2014 on sales of £31.6m.
The company's year end was 30 June 2015. New finance director is Mark Logan, who replaced Keith Lewis in February 2015.
In 2002, total funding for the buyout from US company International Garden Products Inc was £17m, including funds for further expansion.
Thompson & Morgan confirmed that discussions are taking place.