Protect tropical plants as temperatures cool

As night temperatures continue to drop, you should bring in the more sensitive tropical plants like pothos, dumb cane and ficus.

Other more cold tolerant tropical plants can be brought in when night temperatures begin dropping below 40 degrees. A gradual decline in temperatures over a period of time is best as the plants will acclimate some to the cooling weather.

You may want to move the tropical plants in for a night if there has been a long spell of warm weather and a sudden dramatic drop in temperature is predicted. These plants should be gradually acclimated to indoor growing conditions and permanently brought inside before your area's first anticipated frost. The Botanic Garden's first killing frost typically occurs around Oct. 15.

Tender plants can be protected from light freezes by covering them with sheets, plastic or boxes.

Monitor all plants carefully for insects or disease before bringing them in. Discard seriously diseased plants.

• When buying mums, look for plants that are just starting to show color in order to maximize the display time. When purchased at the right time, you can get four to six weeks of good display time with the mums.

Mums with flowers that are fully open will not last as long as those planted in an earlier stage of color. Buy mums with more open flowers if you are planting into a location with shade as mums that are tight in bud (no color showing) may not open when planted in too much shade.

Pay close attention to watering as the mums are often pot bound and will quickly dry out.

• When you buy bulbs in a garden center, pick bulbs that are plump and firm with no mushy spots. Small nicks, loose tunics or blue/gray mold do not affect the development of bulbs.

Bulbs with white mold or that are soft and lightweight with a strong moldy smell are probably not good.

If your bulbs cannot be planted right away, store them in a well-ventilated area that is cool but above freezing, out of reach of rodents and away from ethylene-producing materials such as ripening fruit.

Artificial heat will dry bulbs, while high temperatures may destroy next spring's flower in the bulb.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.