Generally, it can be cured by spraying water for 4 hours after curing (the pressure of spraying water is not easy to be too large, and it is best to flow naturally).

The recommended answer is also good. It was poured several times a few days ago, mainly depending on the dryness of the cement wall surface. When white appears, you can touch the ashes with your hands and water them. Water it for 4-5 times and it will be OK. Not too much.

It doesn't matter if the time is not fixed.