Proper watering of succulent plants and cacti will depend largely on four things: the time of year, how much light the plant receives, the size of the plant, and what kind of container it's planted in.

In general, always water with tepid water as cold water can immediately shock a plant. Sometimes cold water shock will cause succulent plants to drop otherwise healthy leaves.

Both species, cacti and succulents, should be watered in the morning and only on dry days rather than humid or cloudy days. Remember, plants use light to take in moisture through the roots which it disperses and stores in the tissue. Excess moisture evaporates into the air---something that doesn't happen easily when it's humid. If the plant is unable to cycle the water surrounding the roots in this way, the water stands around the roots and encourages them to rot. Cacti and succulent plants are very susceptible to this.

Your cacti and succulent plants will require more water during the spring and through the early fall when they are actively growing. Remember, though, that the cacti are very adept at storing water, so make absolutely certain that the soil has dried completely between waterings, and always err on the side of under-watering. Succulent plants on the other hand, require slightly more water than cacti, so allow the soil to become only moderately dry between waterings.

During their semi-dormant state in the late fall and winter, they will require only enough water to keep them hydrated. Watch for a slight softening of the tissue before you water, again remembering to err on the side of underwatering. You will notice that larger plants, or plants in plastic or glazed ceramic pots, will require less water than those in clay pots.