The Growing Success GrowQube has a new compost and nutrient blend.
The product is being marketed as "easier to use and carry than a growing bag" and its depth achieved through its cube shape is designed to give deeper rooting. RRP is £4.99.
There will be a "heavyweight" marketing spend including an Easter and spring TV campaign.
Richard Carr is now running sales at the company, with Simon McArdle running marketing and Peter Rush as chief executive officer. All are ex-Hozelock.
See more on the opening of Sinclair's £15m plant at Ellesmere Port and on Sinclair's new strategy in Horticulture Week magazine later this month.