Magrath said of the sale: "A sale isn't imminent and could take several months."
He added that company results up to 30 June will show "a major improvement in profitability" which "underpins our confidence for 2016".
He said: "The seed market is competitive and not particularly focussed on increasing market size."
Magrath said improved performance in the yet-to-be-released figures was because of improved operational efficiency (including the implementation of a new ERP system), new products such as Incredibloom fertiliser, Incredicompost, Van Meuwen seeds launch and moves into selling hardy nursery stock, garden equipment and sundries.
T&M says the company is worth £15m. Turnover is £31m.