These plants prefer dry conditions, and are susceptible to rot if left in humid conditions or with damp soil. Always check the soil is completely dry before watering. For plants in pots with drainage holes, water thoroughly and allow the soil to drain and dry out completely between waters. If the pot hasn’t got drainage holes then be careful not to add too much water. In the growing season (during Spring and Summer) these plants will need watering every 1-2 weeks depending on conditions. During the Autumn and Winter months, temperature and daylight hours both decrease, and Cacti and Succulents will require much less water as a result. The soil will also take longer to dry out, so reduce watering frequency to every 4 - 6 weeks.
N.B. If you aren’t sure whether to water or not, remember that these plants are drought resistant, so it’s always better to underwater rather than overwater.