9 Freestanding Greenhouse or Home Attached? There are certainly benefits to each type of greenhouse and should you decide on a home-attached model, it’s important to consider that a concrete foundation may be a better option due to settling or shifting. The next step is deciding what size of greenhouse you need based on available space, gardening needs and budget. What will your garden grow? If you are think- ing citrus trees, a Cape Cod gives you the most height in the greenhouse but a Traditional is most common for gardeners who want to control the temperatures in the winter months — less air volume means less chance for cold air pockets. It is often a combination of function and aesthetics.