The company said is has sold 65 tons of fertiliser and the Daily Mail has given away 27,000 25-litre bags of compost and 100g Incredibloom sachets via a points offer.
Horticulture director Paul Hansord said sales as a result of the promotion were "beyond our wildest dreams".
Meanwhile staff believe the company which is up for sale will be sold by Christmas, with the price thought to be around £10m plus debt.
Chief executive Bryan Magrath has told staff he has not ruled out a management buy out.
Owner, Primary Capital, has cut the 18 interested parties down to five, including at least one private equity group.