Houseplants and leftover holiday plants often look a little bedraggled in late winter. There are several causes for what seems to be declining health and vigor. A few adjustments to correct for winter conditions should perk them up and get them in good shape for a spring energy burst.
It’s not common knowledge, but most houseplants go into dormancy in winter just like outdoor plants. Their growth slows or stops, they need little or no fertilization and less water than in spring and summer when they are actively growing. It’s entirely normal for houseplants such as African violets and Cape primrose (Streptocarpus) which are in flower for 10 months of the year to stop producing any new buds in winter. It’s also normal for Christmas cacti and kalanchoe which were in flower during the holiday season to still be in bloom in late winter or early spring. Winter-blooming plants like them will need feeding until they enter their spring/summer dormancy.
Nine hours a day of weak sunlight under cloudy winter skies does not provide enough light to prevent houseplants from becoming leggy as they stretch (slowly) to the available light source or prevent their leaves from turning light green. Ficus benjamina plants are notorious for dropping most of their leaves in winter. Moving houseplants closer to a light source or providing supplemental light with a full-spectrum light bulb in a nearby lamp should help correct the problem.
Many houseplants are placed on windowsills where they are more visible and get good light. Cold winter temperatures transmit through window glass and can damage plant leaves. Move houseplants away from cold windows in winter and pull down shades at night to protect them.
Too much water will turn houseplant leaves yellow and the plant may droop, as well. Follow the old adage, “Water when necessary, not on a schedule.” Houseplants should be watered when the top inch of soil in a six-inch or smaller pot is dry or when the top two inches of soil has dried in larger pots. That might be only every 10 days or so in winter depending on potting soil type and root development. Use your finger to test soil moisture levels every week in winter. If the soil in a pot has dried out completely, soak the pot in tepid water in the sink until the soil is wet and allow any excess water to drain. Then wait until the top inch or two of soil is dry to water again.
Rootbound plants often suffer more in winter since they have been weakened over time by lack of sufficient water and fertilizer. The first sign that a plant is rootbound is that water runs right through the pot and out the drainhole carrying with it nutrients and fertilizer. That’s because the roots have filled the pot and there’s very little soil left to hold water. Repot rootbound houseplants in late February just as temperatures warm using a good quality potting soil mix appropriate for the plant type and a pot one size larger.
PAR (Plant a Row for the Hungry) has once again organized a citrus collection for the Community Food Bank. It’s Saturday, Feb. 3 from 9 to 11 a.m at the Garden of the Sun, 1750 N. Winery Ave. in southeast Fresno. Due to a quarantine for citrus greening disease, all leaves and stems must be removed.
Also, a free citrus class taught by Fresno County Master Gardener Ron Vivian will be offered at 9 a.m.
Elinor Teague: firstname.lastname@example.org