WINTERTIME HOUSEPLANT CARE

During winter’s brief, dim days, plants that in other seasons prefer a northern or eastern exposure (such as a maidenhair fern and ivies, right) thrive in a south-facing window. On sunny days, sheer curtains or blinds can filter light that is too harsh for these plants’ leaves.

Martha’s tip: Rotate houseplant pots a quarter turn every week. Exposing every leaf to the sunshine enables plants to grow uniformly and maintain a balanced shape.

Although plants’ water needs may lessen in winter, their humidity requirements increase (brown leaf tips are one sign). Pebbles sitting in water inside a ceramic saucer (with a glazed interior, to prevent seepage that can stain wood surfaces) will add moisture to the air. Keep water below tops of pebbles.

Always water enough for some excess to flow out of the pot’s drainage holes, then empty the saucer. Plants in warm rooms dry out sooner than cool room plants. Any with wilted or brown leaves want water. A dry pot weighs much less than a well-watered one, so lifting it and recognizing the difference is a more accurate gauge for watering.

A good time to check for pests is while giving pots the weekly quarter turn that encourages even plant growth. Pinhead-size light-green insects might be aphids, which leave a sticky residue; insecticidal soap will kill them.

White, woolly patches indicate mealybugs. Apply rubbing alcohol to the patches with a cotton swab; then spray with insecticidal soap.

Pale, discolored splotches mean red spider mites. Again, insecticidal soap should take care of the problem.

Even sturdy succulents should be checked for insects during weekly dusting with a soft brush or cloth. Cotton swabs are handy applicators for rubbing alcohol, which removes mealybugs.

The annual slowdown means houseplants need less frequent feedings. For winter-flowering houseplants, soluble food high in phosphorus promotes bud set and bloom. If other plants need winter feeding (most do not), fertilize them at a quarter strength. Miracle-Gro Organic™ Plant Food is a good choice.