Issue: December 11, 2004

Fertilize houseplants in winter

Can I fertilize my houseplants in the winter? If so, how?

Some houseplants will be dormant or their growth will slow in the winter. You can cease fertilizing during this time or at least reduce the amount of fertilizer that they receive.

Houseplants that are actively growing should continue to receive fertilizer with a relatively high level of nitrogen. Nitrogen in fertilizer (the first of three numbers on the label) stimulates growth of leaves and stems. Flowering plants that may be dormant now but preparing to bloom in the spring will benefit from a fertilizer with a relatively greater amount of phosphate (the second of the three numbers). Phosphate benefits development of flowers and fruit. Finally, potash (potassium, the third number) benefits plant health. All are important, but the relative concentrations may determine whether you stimulate vegetative or flowering growth.

These fertilizers may be purchased as liquids that are diluted with water or soluble solids that must be dissolved in water. They may be from organic sources or mineral sources. These diluted or dissolved fertilizers should be used according to the directions on the label. When it is cloudy and during the shorter days, fertilize less. You can make the lower recommended concentrations on the label, or apply the fertilizer less often. When the days lengthen and growth begins, you can increase application of fertilizer. Do this by increasing the concentration of fertilizer (never exceeding the recommendations on the label) or by applying fertilizer more frequently.

It is always wise to apply the fertilizer to a soil that is already moist. If the soil in the container is dry, water to moisten the soil and apply the fertilizer solution a few days later.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!