Notcutts' project follows similar makeovers at Wheatcroft and Tunbridge Wells garden centres. Dalziel and Pow worked on the designs at those centres.
There are new gardening, furniture, home and gifts departments.
The family is the target audience for new pets (including Guinea Pig World), food and play departments.
The 20,000 square metres retractable plantarea roof covers more than a third of its plants department. Rainwater is recycled for watering the plants.
A 'Garden Party' last weekend saw celebrity TV gardener David Domoney and chef Jeremy Pang give talks and demonstrations.
Notcutts has a five-year rolling plan to refurbish its 18 garden centres.