When you can't find a rock in the size or shape desired for your garden, turn to a concrete mixture to make custom artificial rocks. Hypertufa, an artificial form of porous tufa rock, uses concrete, sand and peat moss to create lightweight stones that you can easily move throughout your outdoor space. While you can purchase hypertufa kits for making your own artificial rocks, you can find all the materials needed to make a homemade mixture at any home and garden center.
6 Tips on How to Cure Concrete (Keep Wet)- wikiHow: When To Start Curing Concrete? Absolutely as soon as possible. As soon as it is possible to walk on the concrete without marking it, start curing concrete. For small non documented jobs,continue the process for a minimum of three days, but seven days is better.
Are You Using the Right Cement When Curing Concrete During Winter?