“We have a greenhouse made out of old windows. What is the lowest temperature suggested for winter? This morning, the thermometer read 39° F – is this too low? Most of the plants inside are tropical.” -Dianne

For most tropical houseplants, the minimum recommended temperature is around 55° F, although it really depends on the plant. Some plants respond to colder temperatures by slowing growth or going dormant, which means they may recover when temperatures warm. They will likely not survive temperatures below freezing.

For overwintering tender or sub-tropical landscape plants, temperature tolerance varies widely depending on the plant. Check the plant’s hardiness zone to determine the minimum recommended temperature for that plant.

It would also be helpful to determine if the plant is “root-hardy” at colder temperatures, which means the top of the plant will die back while the roots or bulbs survive. Such plants may be stored in a dormant state and replanted in the spring.

Even if your greenhouse is unheated, it can be a great way to get a head start on spring plantings, or to overwinter plants that otherwise might be suited to a warmer hardiness zone.

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Editorial Contributors
Danny Lipford

Danny Lipford


Danny Lipford is a home improvement expert and television personality who started his remodeling business, Lipford Construction, at the age of 21 in Mobile, Alabama. He gained national recognition as the host of the nationally syndicated television show, Today's Homeowner with Danny Lipford, which started as a small cable show in Mobile. Danny's expertise in home improvement has also led him to be a contributor to popular magazines and websites and the go-to source for advice on everything related to the home. He has made over 200 national television appearances and served as the home improvement expert for CBS's The Early Show and The Weather Channel for over a decade. Danny is also the founder of 3 Echoes Content Studio, TodaysHomeowner.com, and Checking In With Chelsea, a décor and lifestyle blog.

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