What is an essential feature that containers for house plants should have?

Drainage holes are an essential feature for containers used for house plants because they allow excess water to escape, preventing the soil from becoming waterlogged. Proper drainage is crucial because stagnant water can harm the plant's roots, leading to issues such as root rot and other fungal diseases. Healthy root systems require a balance of moisture and air, and drainage holes facilitate this by allowing air to circulate while keeping the soil from becoming overly saturated.

While attractive design, capacity for soil, and colorful patterns may enhance the aesthetic appeal of a planter, they do not directly contribute to the health and growth of the house plants. The presence of drainage holes is a practical consideration that significantly impacts plant care and overall success in maintaining healthy indoor plants.