Tropical plants are native to tropical areas, most of which do not exist within the United States. Most tropical plants can't live in a climate with temperatures under 55 degrees Fahrenheit, according to the University of Illinois. However, you can grow tropical plants indoors year-round as long as long as they have enough light. In fact, many tropical plants are grown indoors because they cannot survive outside in most climates. Whether you grow them indoors or out you need to properly water your tropical plants.
Find out how much water your tropical plants need. Some tropicals are used to swamp-like conditions and need constantly wet soil while tropical succulents need much less water as they are more drought tolerant, according to Colorado State University.
Check the soil moisture around your tropical plant. Place the moisture meter in the plant and look at the reading. If it reads "dry" water the plant. If it reads "moist" or "wet" you will not have to water the plant unless it likes excessively wet soil.
Water the tropical plants until water runs out of the bottom of their containers or, if grown in the ground, until the soil is moist.