The make, model, manufacturer and site of your hobby greenhouse will determine whether or not you need a base.  The base serves to elevate your greenhouse off the ground, gives you room to put down your choice of flooring and provides a structure for you to attach your nursery.  Most greenhouses come with hardware and are predrilled to fit its proprietary base.  For nurseries that don’t require a base, they can be attached directly to the ground with anchors often provided by the manufacturer.  Your hobby greenhouse must be secure enough to stand the test of time and the elements and protect your investment.  The greenhouse can be secured in your site by digging a 4” to 6” trench consistent with the base dimensions of your structure, placing your greenhouse in the trench and back-filling with the removed dirt, gravel or the flooring of your choice.  For a more permanent structure, forgo using the included base and mount the frame, using the pre-drilled holes, to pressure treated 6”x6” or use railroad ties for a more aesthetic look. (Again, use board footage consistent with the diameter of your greenhouse.)

Attached greenhouses and those covered with glass should have a strong concrete or concrete block foundation that extends below the frost line according to local building codes. A 2- to 3-foot-high sidewall can add considerably to the appearance of a greenhouse. Concrete block, stone, or brick are the most popular materials used, but shingle, clapboard, and asbestos rock have also been used.