Most houseplants need irrigating when the top 20 percent of their soil is dry to touch. Give them enough water so that it drains out of the pot, but don’t let the plants sit in saucers filled with standing water. You may need to water more often during warm months or when your indoor heater is on in winter. Plants in small containers dry out faster than those in larger ones. Spathiphyllum prefers moist soil, and Schefflera elegantissima needs consistent watering or it can lose leaves. Irrigate bromeliads by pouring water into their center cups.