Oliver-branded seeds, planters and compost are 350-store Homebase's big brands this season. The range will rival 331-store B&Q's Alan Titchmarsh-backed gardening offer.
But while Oliver can promote Homebase, Titchmarsh can only "offer gardening advice" to B&Q because of his BBC work (HW, 4 February).
B&Q gardening buyer Neil Moroney said: "We're working with Alan Titchmarsh with what we think are the relevant categories. Alan is the number-one gardener and we're the number-one garden centre.
"We're offering advice and making it easier. It's not about celebrity products. We think our products are strong in their own right. We have no plans for product endorsement by celebrities."
A Homebase representative said: "Anything with celebrity branding is going to be very big at Homebase." Channel 4 broadcast 12 programmes in the series Jamie at Home about growing and cooking in late 2007. A second series of 14 programmes aired in 2008.
Meanwhile, B&Q has launched two new brands - Blooma furniture and barbecues and Verve garden equipment - jointly with its French sister company Castorama.
B&Q horticulture manager Steve Guy said the products were "more stylish" and B&Q was using parent company Kingfisher "more to bring value by common sourcing".
More joint brands are coming out in kitchen and bathroom products. B&Q said it will not lose existing brands such as Hozelock and Weber. The brand could extend to hand tools and plants in the future.
B&Q horticulture buyer Joclyn Silezin said grow your own had grown by 75 per cent in four years and now included 500 varieties, with grafted vegetables from Suttons a big line for 2011.
Last year berries, seed potatoes, tomatoes and rhubarb improved sales most. Foxgloves, luopins and sweetpeas are set to do well due to economic reasons, but Silezin was "not so sure" about cut your own replacing the grow your own trend.
B&Q will look to source from New Forest Plants, now that B&Q bedding supplier Roundstone has bought the ornamental grower. Guy said vertical gardening at B&Q's 15m-high RHS Chelsea Flower Show garden was the promotional focus for 2011.