Get ready to move your plants indoors

The last time that I was on the Lawn and Garden Show on WGAC, I received a number of calls on what to do with houseplants that have been outside all summer.

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I have some indoor plants that have been outside all summer, and it is time to get them ready to move back indoors. If you are thinking about buying some houseplants, the same practices that follow will need to be followed for these new plants.

There are several key factors that affect how well a plant will grow and that must be taken into account when bringing a plant into your home. These factors are light, temperature, humidity, water, and the soil. Different houseplants have different needs.

Of all the factors affecting growth, light is the most important for houseplants. In the past, I had a ficus tree that we moved outside every summer. When the ficus was moved back inside, it would lose all of it leaves because of the change in light levels. In a few weeks, it would be full of leaves again.

There are a number of symptoms that will help you determine if your plant is not receiving enough light: the plant doesn't grow; the internodes (spaces between the leaves) on the new growth are much longer than the internodes on the older part of the plant; the new leaves are smaller than the old leaves; the new leaves are a lighter color than the older leaves; and the older leaves are dead or fall off the plant.

Houseplants are divided into four groups based on light requirements. These are low light, which is 25 to 75 foot candles; medium light, which is 75 to 150 foot candles; high light, which is 150 to 1,000 foot candles; and very high, which is more than 1,000 foot candles.

A foot candle is the unit of measurement for the amount of light that is cast by a candle on a white surface one foot away in a completely dark room. To determine the amount of light, you can buy a light meter or if you have a 35mm camera you can use the f-stop to determine the amount of light. If you have a plant that requires more light than you have available, a possible solution is to add an artificial light source. Another way to solve the problem is to increase the number of hours that a plant receives light. An example would be giving the plant 16 hours of light and eight hours of darkness.

The next most important factor affecting houseplants is temperature. Most houseplants can tolerate temperatures down to 55 degrees. I try to move my plants indoors when the temperature is around 55 degrees at night. Most houseplants come from tropical or subtropical areas of the world. Therefore, they like temperatures in the range of 58 to 86 degrees. However, the best range is 70 to 80 degrees during the day and 65 to 70 degrees at night.

These houseplants also are adapted to an area with high humidity levels. One reason that houseplants do so well outside here is the high humidity levels that we have. When we move plants from outside to indoors, they are moving into an area with a lower humidity level. Most homes have a humidity level of 10 to 30 percent, so we need to take steps to insure that the plants have the right humidity levels. You can place plants close together to create a microenvironment with a higher relative humidity. Also, you can use a shallow container filled with water and lava rocks or gravel, which will provide evaporation from a large surface area and increase relative humidity. Another option is to use a humidifier.

The last two factors that affect houseplants are improper watering and soil.

Soils that hold too much moisture and over-watering can cause major plant problems. There is an easy way to determine if your plant needs water: insert your finger an inch or so below the surface of the soil. If the soil is still moist, no further water is needed. You need to water only when the soil is dry.

You can find out more information on individual houseplants from our publication on houseplants at pubs.caes.uga.edu/caespubs/pubcd/B1318/B1318.htm.

Columbia County Extension Agent Charles Phillips can be reached at (706) 868-3413 or by e-mail at charlesp@uga.edu. The Extension Web address is www.ugaextension.com/columbia.