Just buy portland cement and mix with sand or fine gravel from the parking lot. We don't use any gravel, just a mixture of a few types of cement and sand is cheaper. The gravel/stone isn't needed for sticking cement to PVC. Sakrete is selling you the sand and pea gravel with about 5 pounds of cement per 60# bag. 60-80# bags of portland cement go a long way for under 10 bucks.
If concerned about frost, cover unit bases with straw for a few days. Good to go!
Last edited by Peepaw; 02/22/13 10:34 AM.
