Cacti depending on the species can take long periods of dry conditions . If you are looking for an ideal watering schedule a timetable may not serve your plants very well . All cacti and succulents like to dry out completely and then be watered thoroughly . For plants in portable pots, a large container that can hold water to a minimum depth of halfway up the pot (to be watered) Let the plant set in the container until the surface of the soil is evenly moist . For plants in less or non portable containers a wooden dowel is a good way to check the moisture level in the soil . If the dowel comes out dry after you have inserted it to the bottom of the pot then it is time to water . A drip system is best . A hose or nozzle set at a trickle will work but you still need to probe to determine if your plant has been thoroughly watered.