Most tropical plants, from the philodendrons to the crotons, to the dracaenas and banana trees, need to be brought in before it starts getting below 50 degrees at night.

In the next couple of weeks, gardeners will have to make some tough decisions that are boiled down to expense and space: what plants to bring indoors?

It’s an age-old question. Most of us look at plants in pots on the patio or in the ground and see dollar signs. We know how much money we paid for them, and how much money and time we have invested in them. If you have an abundance of tropical plants in your landscape, the decision is harder.

First, let’s be upfront: It is not against the law if a plant dies due to neglect — as long as it’s yours. Second, letting plants die keeps garden centers and nurseries in business. Third, the agony of death is over and done with the first frost or freeze. You don’t have to experience the slow death that some plants experience indoors.

On the other hand, some plants will survive nicely indoors, while others need special attention. Most tropical plants, from the philodendrons to the crotons to the dracaenas and banana trees, need to be brought in before it starts getting below 50 degrees at night. Cold night temperatures can mean the death of these plants.

On the other hand, many orchids prefer cooler temperatures to set their flower buds and can be kept outside until frost. Watch them carefully because one frost can be enough to kill them.

Some tropical plants do better with the cold than others. Birds-of-paradise seem to tolerate some chilling temperatures, as well as the antirrhinums. But it’s tough to put them in categories without some experience. A plant that might tolerate colder temperatures in your yard can die in another. Air temperatures due to little microclimates vary from yard to yard.

Ideally, it’s best to move the plants inside for one hour a day for the first day, and then take it back outside. Day two is two hours indoors, and then back outside again. Day three is three hours indoors, and so on. After a week and a half, the plant should be acclimated to the reduced light levels found indoors with few problems.

Of course, this all takes place in an ideal world where pensions are fully funded, there is world peace and everyone has a good meal and health care. In reality, we don’t have the time, patience or energy. Pots can get heavy, and moving them here and there can get wearisome. So, it’s usually an outdoor-to-indoors, one-time exchange.

This means we must be prepared that leaves will turn yellow and drop. It also means clearing out as much space as possible around the south windows to reduce the chance of yellow leaves. A double-paned window cuts down about 85 to 90 percent of the available light. That seems drastic, but it gives you a clue as to how much light is present outdoors.

Generally, plants on the north side of the house will get more light outdoors than those placed in front of a southern exposure window indoors, which is why plants still turn yellow and drop older leaves.

Check plants over thoroughly outdoors. More than likely, there are six-legged and eight-legged creatures on the underside of the leaves and/or in the soil. Many are being kept in check by other six-legged and eight-legged creatures that decide not to hitchhike indoors. Without the predators, the “baddies” will have nothing to restrict their growth or movement.

Insecticidal soap is a great alternative. Unfortunately, you really can’t go out and make your own home remedy because household soaps and detergents tend to kill leaves as much as they do insects. However, washing plants with a good stream of water and a washcloth may remove many harmful creatures. Flood the container with water over the course of several days to drown any creatures buried in the soil. Just make sure the container drains and water doesn’t build up.

Also, to cut down on creatures moving indoors, keep outdoor plants separated from those that haven’t been outside. While some creatures fly and crawl, many of the harmful ones don’t move much.

Don’t forget the saucers when plants are indoors, or something to catch the water and creatures that might move out. Keep plants as close to the windows as possible when indoors for the first couple of weeks. If the days turn gray and cloudy, keep some lights on until midnight so that the plants get some light.

Indoors, you won’t have to water as much. Wait until the soil starts drying out before watering. That’s another way for plants to get used to the fact that ideal growing conditions are a summer memory.

David Robson is a horticulture educator for the University of Illinois Extension. For more gardening information or for your local extension unit office, go to The Sangamon-Menard Unit Sangamon County office can be reached at 782-4617.