Jan 04,2008 00:00
Q: Back in the fall, I brought in many of my favorite houseplants and potted plants from the patio and they are looking horrible. Should I fertilize them now or wait until spring? If I wait much longer, I am not sure if any of them will be left. They are dropping leaves all over and the remaining leaves are turning yellow.
A: It can be a fun project to bring plants indoors during the winter. It is a mini-garden that helps filter indoor air and helps relieve stress. It is a great feeling of accomplishment to set the plants back outside in the spring, knowing that you were successful. Some plants even bloom for awhile, helping to brighten up a dull winter day.
Keeping plants over the winter can be difficult if you can't provide the proper growing conditions. Some plants will tolerate a wide range of conditions while some are more limited. The amount of sunlight, humidity, soil, air temperature, soil moisture and fertilizer are all important.
The individual leaves on many plants will grow in relation to the environmental conditions they encounter. If conditions change dramatically, those leaves could become a detriment to the plant. For instance, a leaf that originally grew in sunshine might have several layers of cells near the surface to prevent it from being sunburned. But if the plant is moved into the shade, those layers block too much light from reaching the leaf's chlorophyll; therefore, the plant needs to drop this leaf and grow a new one designed for shady conditions.
Your plants are probably reacting to the new environmental conditions. This is normal and will happen again in the spring when they are moved outside, because new leaves that sprouted indoors might not do well outdoors. Typically, we don't want to give plants too much fertilizer when they are moved indoors; we want the plants to go dormant for awhile. This way they won't add a lot of new growth.
Your plants could probably use a little fertilizer to help them replace some of the lost leaves. Use a slow release fertilizer with a formulation that is nearly equal between the three main ingredients of nitrogen, phosphorus and potassium. You don't want to use a fertilizer with an ingredient much higher than the other two, because you don't want to promote flowering.
Another possibility is that the are getting too much or too little water. Because they are in a new environment, the plants will need to be watered appropriately. They should not be on the same watering time schedule as they were outdoors.
Check to see if any of the plants are getting blasted by a warm air vent that will dry them out quickly. Plants near a cold draft from a window or door will also have problems. Plants that need full sun outdoors should be close to the windows, and plants that prefer shade need to be farther away or near north-facing windows.
Insect populations that were held in check outdoors by weather conditions, predators or parasites might expand rapidly indoors where conditions are more favorable. Also, plants that are in poor health are less able to resist insects. Insects that used the flowerpots for shelter, but ventured out to feed, are going to find less to eat around the pot and will have to start venturing farther into the house. The kitchen will be a great new territory to explore because of potential food sources.
In the fall, many insects begin laying eggs or go dormant in a pupa stage to survive the winter. They might begin hatching after what feels like a very short winter to them. You should inspect the leaves that remain on the plants to look for any insect problems. The closer the plants have been stored indoors, the more potential for insects to transfer from one plant to another.
In the end, you will have to decide which plants are worth keeping and which ones aren't worth the time, effort or electricity of a grow light to try to keep alive all winter.
E-mail questions to Jeff Rugg at firstname.lastname@example.org.
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