When you are designing a garden center there are many considerations you take into account: location, product mix, store layout, advertising, the amount of parking needed, employee training, etc. And while no aspect of building a garden center is more important than another, the physical greenhouse structure is a critical component.
Mistake #1: Not including a greenhouse as part of your garden center design
Today, consumers looking for plants expect to be able to get them from a greenhouse. Even the big box stores recognise this, look at Home Depot, Lowes, and Walmart, and you will see a greenhouse structure either attached to the big warehouse, or located in the middle of the parking lot. They do this because they know that shoppers associate being in the greenhouse with fresh plants, and the greenhouse environment helps keep the plants healthier. Independent Garden Centers have an advantage over the big box stores if you design your store around the greenhouse customers will recognise you as the grower, and associate your plants and employees as knowledgable horticultural experts. Of course you need to follow through and have a staff that really do know how to care for the plants.