QUESTION: Should I fertilize and water my trees during the winter? How about my house plants?

ANSWER: Fertilizing of trees and shrubs during the winter in the high desert should not be done. Fertilizer could stimulate plants to come out of dormancy and start to grow and winter damage could occur. These plants are "resting" above the ground but do have activity in the roots if soil temperatures are warm. Normally trees and shrubs that go into winter with adequate soil moisture do not need watering during the winter. Usually winter rains or snow provide enough water. Deciduous plants do not need much water because the leaves, where transpiration occurs, are gone and nutrients needed for growth are not required because there is no shoot growth. The same holds true for most evergreen plants such as pines, junipers, and native oak trees. When the soil and air temperatures are cold and sun light is reduced why grow? That is what spring, summer, and fall are for!

Houseplants are generally tropical in origin and survive best in warm humid environments. Houseplants need to be watered because of the limited soil volume they are confined to. House temperatures are warm and allow plants to continue to grow. The best way to determine soil moisture is to stick a finger in the soil one to two inches. If the soil feels dry, water; if soil feels moist, don't water.

Fertilizing houseplants during the winter months is not encouraged because of reduced light from the sun. However, if you are "spoon feeding" your plants, that is giving a little fertilizer at each watering, cut back on the fertilizer by giving 1/4 to 1/2 the normal amount.

Many house plants need high humidity to be "happy", especially true with ferns. With forced air heating in many homes, house humidity can be lower during the winter than during the hot summer because of swamp cooler use. Humidity can be created by placing the potted plant on top of a pebble filled shallow dish. Fill the dish with water as needed, maintaining the water level near the top. The dish should have a diameter nearly as large as the plant diameter. The pebbles are important so that the potted plant is not sitting in water which will cause soil saturation and thus root rot. As the water evaporates, a humid environment is created in which a tropical plant will grow and thrive. This is much better than using a squirt bottle three times a day to try and humidify the plant!